1
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Pauziene N, Ranceviene D, Rysevaite-Kyguoliene K, Inokaitis H, Saburkina I, Plekhanova K, Sabeckiene D, Sabeckis I, Martinaityte R, Pilnikovaite E, Pauza DH. Comparative analysis of intracardiac neural structures in the aged rats with essential hypertension. Anat Rec (Hoboken) 2023; 306:2313-2332. [PMID: 36342958 DOI: 10.1002/ar.25109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/16/2022] [Accepted: 10/09/2022] [Indexed: 11/09/2022]
Abstract
Persistent arterial hypertension initiates cardiac autonomic imbalance and alters cardiac tissues. Previous studies have shown that neural component contributes to arterial hypertension etiology, maintenance, and progression and leads to brain damage, peripheral neuropathy, and remodeling of intrinsic cardiac neural plexus. Recently, significant structural changes of the intracardiac neural plexus were demonstrated in young prehypertensive and adult hypertensive spontaneously hypertensive rats (SHR), yet structural alterations of intracardiac neural plexus that occur in the aged SHR remain undetermined. Thus, we analyzed the impact of uncontrolled arterial hypertension in old (48-52 weeks) SHR and the age-matched Wistar-Kyoto rats (WKY). Intrinsic cardiac neural plexus was examined using a combination of immunofluorescence confocal microscopy and transmission electron microscopy in cardiac sections and whole-mount preparations. Our findings demonstrate that structural changes of intrinsic cardiac neural plexus caused by arterial hypertension are heterogeneous and may support recent physiological implications about cardiac denervation occurring together with the hyperinnervation of the SHR heart. We conclude that arterial hypertension leads to (i) the decrease of the neuronal body area, the thickness of atrial nerves, the number of myelinated nerve fibers, unmyelinated axon area and cumulative axon area in the nerve, and the density of myocardial nerve fibers, and (ii) the increase in myelinated nerve fiber area and density of neuronal bodies within epicardiac ganglia. Despite neuropathic alterations of myelinated fibers were exposed within intracardiac nerves of both groups, SHR and WKY, we consider that the determined significant changes in structure of intrinsic cardiac neural plexus were predisposed by arterial hypertension.
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Affiliation(s)
| | | | | | | | - Inga Saburkina
- Lithuanian University of Health Sciences, Kaunas, Lithuania
| | | | | | - Ignas Sabeckis
- Lithuanian University of Health Sciences, Kaunas, Lithuania
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2
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Huang TC, Lo LW, Chou YH, Lin WL, Chang SL, Lin YJ, Liu SH, Cheng WH, Liu PY, Chen SA. Renal denervation reverses ventricular structural and functional remodeling in failing rabbit hearts. Sci Rep 2023; 13:8664. [PMID: 37248400 DOI: 10.1038/s41598-023-35954-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 05/26/2023] [Indexed: 05/31/2023] Open
Abstract
Renal denervation (RDN) suppresses the activity of the renin-angiotensin-aldosterone system and inflammatory cytokines, leading to the prevention of cardiac remodeling. Limited studies have reported the effects of renal denervation on ventricular electrophysiology. We aimed to use optical mapping to evaluate the effect of RDN on ventricular structural and electrical remodeling in a tachycardia-induced cardiomyopathy rabbit model. Eighteen rabbits were randomized into 4 groups: sham control group (n = 5), renal denervation group receiving RDN (n = 5), heart failure group receiving rapid ventricular pacing for 1 month (n = 4), and RDN-heart failure group (n = 4). Rabbit hearts were harvested for optical mapping. Different cycle lengths were paced (400, 300, 250, 200, and 150 ms), and the results were analyzed. In optical mapping, the heart failure group had a significantly slower epicardial ventricular conduction velocity than the other three groups. The RDN-heart failure, sham control, and RDN groups had similar velocities. We then analyzed the 80% action potential duration at different pacing cycle lengths, which showed a shorter action potential duration as cycle length decreased (P for trend < 0.01), which was consistent across all groups. The heart failure group had a significantly longer action potential duration than the sham control and RDN groups. Action potential duration was shorter in the RDN-heart failure group than the heart failure group (P < 0.05). Reduction of conduction velocity and prolongation of action potential duration are significant hallmarks of heart failure, and RDN reverses these remodeling processes.
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Affiliation(s)
- Ting-Chun Huang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Division of Cardiology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Li-Wei Lo
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan.
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan.
| | - Yu-Hui Chou
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan
| | - Wei-Lun Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
| | - Shih-Lin Chang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
| | - Yenn-Jiang Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
| | - Shin-Huei Liu
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
| | - Wen-Han Cheng
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, 11217, Taipei, Taiwan
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
| | - Ping-Yen Liu
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Division of Cardiology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Ann Chen
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan
- National Chung Hsing University, Taichung, Taiwan
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3
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Karim S, Chahal A, Khanji MY, Petersen SE, Somers V. Autonomic Cardiovascular Control in Health and Disease. Compr Physiol 2023; 13:4493-4511. [PMID: 36994768 PMCID: PMC10406398 DOI: 10.1002/cphy.c210037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Autonomic neural control of the cardiovascular system is formed of complex and dynamic processes able to adjust rapidly to mitigate perturbations in hemodynamics and maintain homeostasis. Alterations in autonomic control feature in the development or progression of a multitude of diseases with wide-ranging physiological implications given the neural system's responsibility for controlling inotropy, chronotropy, lusitropy, and dromotropy. Imbalances in sympathetic and parasympathetic neural control are also implicated in the development of arrhythmia in several cardiovascular conditions sparking interest in autonomic modulation as a form of treatment. A number of measures of autonomic function have shown prognostic significance in health and in pathological states and have undergone varying degrees of refinement, yet adoption into clinical practice remains extremely limited. The focus of this contemporary narrative review is to summarize the anatomy, physiology, and pathophysiology of the cardiovascular autonomic nervous system and describe the merits and shortfalls of testing modalities available. © 2023 American Physiological Society. Compr Physiol 13:4493-4511, 2023.
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Affiliation(s)
- Shahid Karim
- Mayo Clinic, Rochester, Minnesota, USA
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
| | - Anwar Chahal
- Mayo Clinic, Rochester, Minnesota, USA
- University of Pennsylvania, Pennsylvania, USA
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
| | - Mohammed Y. Khanji
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Newham University Hospital, Barts Health NHS Trust, London, UK
| | - Steffen E. Petersen
- William Harvey Research Institute, NIHR Barts Biomedical Centre, Queen Mary University London, UK
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, UK
- Health Data Research UK, London, UK
- Alan Turing Institute, London, UK
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Caldwell JL, Lee IJ, Ngo L, Wang L, Bahriz S, Xu B, Bers DM, Navedo MF, Bossuyt J, Xiang YK, Ripplinger CM. Whole-heart multiparametric optical imaging reveals sex-dependent heterogeneity in cAMP signaling and repolarization kinetics. SCIENCE ADVANCES 2023; 9:eadd5799. [PMID: 36662864 PMCID: PMC9858506 DOI: 10.1126/sciadv.add5799] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Cyclic adenosine 3',5'-monophosphate (cAMP) is a key second messenger in cardiomyocytes responsible for transducing autonomic signals into downstream electrophysiological responses. Previous studies have shown intracellular heterogeneity and compartmentalization of cAMP signaling. However, whether cAMP signaling occurs heterogeneously throughout the intact heart and how this drives sex-dependent functional responses are unknown. Here, we developed and validated a novel cardiac-specific fluorescence resonance energy transfer-based cAMP reporter mouse and a combined voltage-cAMP whole-heart imaging system. We showed that in male hearts, cAMP was uniformly activated in response to pharmacological β-adrenergic stimulation. In contrast, female hearts showed that cAMP levels decayed faster in apical versus basal regions, which was associated with nonuniform action potential changes and notable changes in the direction of repolarization. Apical phosphodiesterase (PDE) activity was higher in female versus male hearts, and PDE inhibition prevented repolarization changes in female hearts. Thus, our imaging approach revealed sex-dependent regional breakdown of cAMP and associated electrophysiological differences.
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Affiliation(s)
| | - I-Ju Lee
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Lena Ngo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Lianguo Wang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Sherif Bahriz
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Bing Xu
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- VA Northern California, Mather, CA, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Manuel F. Navedo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Julie Bossuyt
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Yang K. Xiang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- VA Northern California, Mather, CA, USA
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5
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Wang X, Qian Y, Yao Y, Wang Y, Zhang Y, Zhang S, Zhao Q. Median nerve stimulation elevates ventricular fibrillation threshold via the cholinergic anti-inflammatory pathway in myocardial infarction canine model. Front Cardiovasc Med 2022; 9:904117. [DOI: 10.3389/fcvm.2022.904117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 11/09/2022] [Indexed: 12/02/2022] Open
Abstract
BackgroundMedian nerve stimulation (MNS) diminishes regional myocardial ischemia and ventricular arrhythmia; however, the underlying mechanism has not been elucidated.MethodsIn this study, we randomly categorized 22 adult mongrel dogs into a control group, MNS group 1, and MNS group 2. After a 4-week experimental myocardial infarction (MI), ventricular electrophysiology was measured in the MNS group 1 before and after 30 min of MNS. The same measurements were performed in the MNS group 2 dogs via bilateral vagotomy. Venous blood and ventricular tissue were collected to detect molecular indicators related to inflammation and cholinergic pathways by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and Western blot (WB).ResultsNo significant changes were reported in the ventricular effective refractory period (ERP) in the MNS group 1 and MNS group 2 dogs before and after MNS. The ventricular fibrillation threshold (VFT) in the MNS group 1 was significantly higher than that in the MNS group 2 (20.3 ± 3.7 V vs. 8.7 ± 2.9 V, P < 0.01). The levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and nuclear transcription factor-κB (NF-κB) were lower (P < 0.01), whereas the levels of Ach were higher in the peri-infarct zone tissues in the MNS group 1 dogs than those in the MNS group 2 dogs (P < 0.01).ConclusionThis study demonstrated that MNS increases VFT in a canine model with MI. The effects of MNS on VFT are potentially associated with the cholinergic anti-inflammatory pathway.
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Melatonin and the Brain–Heart Crosstalk in Neurocritically Ill Patients—From Molecular Action to Clinical Practice. Int J Mol Sci 2022; 23:ijms23137094. [PMID: 35806098 PMCID: PMC9267006 DOI: 10.3390/ijms23137094] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 01/27/2023] Open
Abstract
Brain injury, especially traumatic brain injury (TBI), may induce severe dysfunction of extracerebral organs. Cardiac dysfunction associated with TBI is common and well known as the brain–heart crosstalk, which broadly refers to different cardiac disorders such as cardiac arrhythmias, ischemia, hemodynamic insufficiency, and sudden cardiac death, which corresponds to acute disorders of brain function. TBI-related cardiac dysfunction can both worsen the brain damage and increase the risk of death. TBI-related cardiac disorders have been mainly treated symptomatically. However, the analysis of pathomechanisms of TBI-related cardiac dysfunction has highlighted an important role of melatonin in the prevention and treatment of such disorders. Melatonin is a neurohormone released by the pineal gland. It plays a crucial role in the coordination of the circadian rhythm. Additionally, melatonin possesses strong anti-inflammatory, antioxidative, and antiapoptotic properties and can modulate sympathetic and parasympathetic activities. Melatonin has a protective effect not only on the brain, by attenuating its injury, but on extracranial organs, including the heart. The aim of this study was to analyze the molecular activity of melatonin in terms of TBI-related cardiac disorders. Our article describes the benefits resulting from using melatonin as an adjuvant in protection and treatment of brain injury-induced cardiac dysfunction.
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Zhu C, Rajendran PS, Hanna P, Efimov IR, Salama G, Fowlkes CC, Shivkumar K. High-resolution structure-function mapping of intact hearts reveals altered sympathetic control of infarct border zones. JCI Insight 2022; 7:153913. [PMID: 35132963 PMCID: PMC8855798 DOI: 10.1172/jci.insight.153913] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Remodeling of injured sympathetic nerves on the heart after myocardial infarction (MI) contributes to adverse outcomes such as sudden arrhythmic death, yet the underlying structural mechanisms are poorly understood. We sought to examine microstructural changes on the heart after MI and to directly link these changes with electrical dysfunction. We developed a high-resolution pipeline for anatomically precise alignment of electrical maps with structural myofiber and nerve-fiber maps created by customized computer vision algorithms. Using this integrative approach in a mouse model, we identified distinct structure-function correlates to objectively delineate the infarct border zone, a known source of arrhythmias after MI. During tyramine-induced sympathetic nerve activation, we demonstrated regional patterns of altered electrical conduction aligned directly with altered neuroeffector junction distribution, pointing to potential neural substrates for cardiac arrhythmia. This study establishes a synergistic framework for examining structure-function relationships after MI with microscopic precision that has potential to advance understanding of arrhythmogenic mechanisms.
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Affiliation(s)
- Ching Zhu
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Pradeep S Rajendran
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Peter Hanna
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Guy Salama
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Charless C Fowlkes
- Department of Computer Science, University of California, Irvine, Irvine, California, USA
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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8
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Nicolson WB, Smith MI, Vali Z, Samani NJ, Ng GA. Application of two novel electrical restitution-based ECG markers of ventricular arrhythmia to patients with nonischemic cardiomyopathy. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2021; 44:284-292. [PMID: 33336815 DOI: 10.1111/pace.14143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/18/2020] [Accepted: 12/06/2020] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Sudden cardiac death (SCD) risk assessment is limited, particularly in patients with nonischemic cardiomyopathies. This is the first application, in patients with cardiomyopathies, of two novel risk markers, regional restitution instability index (R2I2) and peak electrocardiogram restitution slope (PERS), which have been shown to be predictive of ventricular arrhythmias (VA) or death in ischemic heart disease patients. METHODS Blinded retrospective study of 50 patients: 33 dilated cardiomyopathy and 17 other; undergoing electrophysiological study (EPS) for SCD risk stratification, and 29 controls with structurally normal hearts undergoing EPS. R2I2 was calculated from an EPS using electrocardiogram surrogates for action potential duration and diastolic interval. Cut-offs for high and low R2I2/PERS were predefined. RESULTS R2I2 was significantly higher in study than control patients (0.99 ± 0.05 vs. 0.63 ± 0.04, p < .001). PERS showed a trend to higher values in the study group (1.18[0.63] vs. 1.09[0.54], p = .07). During median follow up of 5.6 years [interquartile range 1.9 years], nine study patients reached the endpoint of VA/death. Patients who experienced VA/death showed trends to higher mean R2I2 (1.14 ± 0.07 vs.0.95 ± 0.05, p = .12) and PERS (1.46[0.49] vs. 1.13[0.62], p = .22). A Cox proportional hazards model using grouped markers: R2I2 < 1.03 + PERS < 1.21/either R2I2 ≥ 1.03 or PERS ≥ 1.21/R2I2 ≥ 1.03 + PERS ≥ 1.21; significantly predicted VA/death (p = .02) with a hazard ratio per positive component of 3.2 (95% confidence interval 1.2-8.8). CONCLUSION R2I2≥ 1.03 + PERS ≥ 1.21 may predict VA/death in patients with cardiomyopathies. R2I2 ≥ 1.03 + PERS ≥ 1.21 have the potential to play an important role in SCD risk stratification in cardiomyopathies but their validity should be confirmed in a larger study.
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Affiliation(s)
- William B Nicolson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, UK.,University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Matthew I Smith
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Zakariyya Vali
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, UK
| | - Nilesh J Samani
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, UK.,University Hospitals of Leicester NHS Trust, Leicester, UK
| | - G André Ng
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, UK.,University Hospitals of Leicester NHS Trust, Leicester, UK
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Tan C, Yi X, Chen Y, Wang S, Ji Q, Li F, Wang Y, Zou R, Wang C. The Changes of T-Wave Amplitude and QT Interval Between the Supine and Orthostatic Electrocardiogram in Children With Dilated Cardiomyopathy. Front Pediatr 2021; 9:680923. [PMID: 34295860 PMCID: PMC8290918 DOI: 10.3389/fped.2021.680923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/24/2021] [Indexed: 11/24/2022] Open
Abstract
Objectives: Electrocardiogram (ECG) can be affected by autonomic nerves with body position changes. The study aims to explore the ECG changes of children with dilated cardiomyopathy (DCM) when their posture changes. Materials and methods: Sixty-four children diagnosed with DCM were recruited as research group and 55 healthy children as control group. T-wave amplitude and QT interval in ECG were recorded, and their differences between supine and orthostatic ECG were compared in both groups. Subsequently, the children with DCM were followed up and the differences before and after treatment compared. Results: ① Comparisons in differences: Differences of T-wave amplitude in lead II and III, aVF, and V5 and differences of QT interval in lead II, aVL, aVF, and V5 were lower in the research group than in the control group. ② Logistic regression analysis and diagnostic test evaluation: The differences of T-wave amplitude in lead III and QT interval in lead aVL may have predictive value for DCM diagnosis. When their values were 0.00 mV and 30 ms, respectively, the sensitivity and specificity of the combined index were 37.5 and 83.6%. ③ Follow-up: In the response group, the T-wave amplitude difference in lead aVR increased and the difference of QT interval in lead V6 decreased after treatment. In the non-response group, there was no difference before and after treatment. When the combined index of the differences of T-wave amplitude difference in lead aVR and QT interval difference in lead V6, respectively, were -0.05 mV and 5 ms, the sensitivity and specificity of estimating the prognosis of DCM were 44.4 and 83.3%. Conclusions: The differences of T-wave amplitude and QT interval may have a certain value to estimate DCM diagnosis and prognosis.
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Affiliation(s)
- Cheng Tan
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics, The Affiliated Zhuzhou Hospital, Xiangya School of Medicine, Central South University, Zhuzhou, China
| | - Xiuying Yi
- Department of Pediatrics, The Affiliated Zhuzhou Hospital, Xiangya School of Medicine, Central South University, Zhuzhou, China
| | - Ying Chen
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics, The Affiliated Zhuzhou Hospital, Xiangya School of Medicine, Central South University, Zhuzhou, China
| | - Shuangshuang Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics, The Affiliated Zhuzhou Hospital, Xiangya School of Medicine, Central South University, Zhuzhou, China
| | - Qing Ji
- Department of Pediatrics, The Affiliated Zhuzhou Hospital, Xiangya School of Medicine, Central South University, Zhuzhou, China
| | - Fang Li
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yuwen Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Runmei Zou
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Cheng Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
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Pedrosa RC. Dysautonomic Arrhythmogenesis: A Working Hypothesis in Chronic Chagas Cardiomyopathy. INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2020. [DOI: 10.36660/ijcs.20200169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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11
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Chen M, Li X, Wang S, Yu L, Tang J, Zhou S. The Role of Cardiac Macrophage and Cytokines on Ventricular Arrhythmias. Front Physiol 2020; 11:1113. [PMID: 33071805 PMCID: PMC7540080 DOI: 10.3389/fphys.2020.01113] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
In the heart, cardiac macrophages have widespread biological functions, including roles in antigen presentation, phagocytosis, and immunoregulation, through the formation of diverse cytokines and growth factors; thus, these cells play an active role in tissue repair after heart injury. Recent clinical studies have indicated that macrophages or elevated inflammatory cytokines secreted by macrophages are closely related to ventricular arrhythmias (VAs). This review describes the role of macrophages and macrophage-secreted inflammatory cytokines in ventricular arrhythmogenesis.
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Affiliation(s)
- Mingxian Chen
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xuping Li
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Songyun Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jianjun Tang
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Shenghua Zhou
- The Second Xiangya Hospital, Central South University, Changsha, China
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12
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Wang Y, Yu L, Po SS. Ablation of Neuroaxial in Patients with Ventricular Tachycardia. Card Electrophysiol Clin 2020; 11:625-634. [PMID: 31706470 DOI: 10.1016/j.ccep.2019.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ventricular tachycardia (VT) remains a common cause of sudden cardiac death. It is widely accepted that VTs are strongly associated with autonomic imbalance with reduced vagal and increased sympathetic activities. Pharmacologic therapy remains the first-line therapy, but antiarrhythmic agents may not be effective or carry significant side effects. Sympathetic denervation is an emerging therapy to prevent or treat VTs by rebalancing the sympathetic and parasympathetic activity. This article focuses on the role of sympathetic activation in VT, and the mapping and ablation of sympathetic nervous system in patients with VT.
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Affiliation(s)
- Yuhong Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, No. 9 ZhangZhiDong Street, Wuchang District, Wuhan, Hubei, China
| | - Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, No. 9 ZhangZhiDong Street, Wuchang District, Wuhan, Hubei, China
| | - Sunny S Po
- Department of Medicine, Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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13
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Ibrahim MS, Samuel B, Mohamed W, Suchdev K. Cardiac Dysfunction in Neurocritical Care: An Autonomic Perspective. Neurocrit Care 2020; 30:508-521. [PMID: 30484009 DOI: 10.1007/s12028-018-0636-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A number of neurologic disorders can cause cardiac dysfunction by involving the conductive system and contractile apparatus of the heart. This is especially prominent in the neurocritical care setting where the spectrum of cardiac dysfunction due to acute neurologic injury ranges from trivial and isolated electrocardiographic changes to malignant arrhythmias and sudden death (Table 1). The mechanism of these cardiac complications is complex and not fully understood. An understanding of the neuroanatomical structures and pathways is of immense importance to comprehend the underlying pathophysiology that culminates as cardiac damage and dysregulation. Once the process is initiated, it can complicate and adversely affect the outcome of primary neurologic conditions commonly seen in the neurocritical care setting. Not only are these cardiac disorders under-recognized, there is a paucity of data to formulate evidence-based guidelines regarding early detection, acute management, and preventive strategies. However, certain details of clinical features and their course combined with location of primary neurologic lesion on neuroimaging and data obtained from laboratory investigations can be of great value to develop a strategy to appropriately manage these patients and to prevent adverse outcome from these cardiac complications. In this review, we highlight the mechanisms of cardiac dysfunction due to catastrophic neurologic conditions or due to stress of critical illness. We also address various clinical syndromes of cardiac dysfunction that occur as a result of the neurologic illness and in turn may complicate the course of the primary neurologic condition.
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Affiliation(s)
- Mohammad S Ibrahim
- Department of Neurology, Division of Neurocritical care, Wayne State University School of Medicine, Detroit, MI, USA
| | - Bennson Samuel
- Department of Neurology, Division of Neurocritical care, Wayne State University School of Medicine, Detroit, MI, USA
| | - Wazim Mohamed
- Department of Neurology, Division of Neurocritical care, Wayne State University School of Medicine, Detroit, MI, USA
| | - Kushak Suchdev
- Department of Neurology, Division of Neurocritical care, Wayne State University School of Medicine, Detroit, MI, USA.
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14
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Kim TY, Jeng P, Hwang J, Pfeiffer Z, Patel D, Cooper LL, Kossidas K, Centracchio J, Peng X, Koren G, Qu Z, Choi BR. Short-Long Heart Rate Variation Increases Dispersion of Action Potential Duration in Long QT Type 2 Transgenic Rabbit Model. Sci Rep 2019; 9:14849. [PMID: 31619700 PMCID: PMC6795902 DOI: 10.1038/s41598-019-51230-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/24/2019] [Indexed: 01/21/2023] Open
Abstract
The initiation of polymorphic ventricular tachycardia in long QT syndrome type 2 (LQT2) has been associated with a characteristic ECG pattern of short-long RR intervals. We hypothesize that this characteristic pattern increases APD dispersion in LQT2, thereby promoting arrhythmia. We investigated APD dispersion and its dependence on two previous cycle lengths (CLs) in transgenic rabbit models of LQT2, LQT1, and their littermate controls (LMC) using random stimulation protocols. The results show that the short-long RR pattern was associated with a larger APD dispersion in LQT2 but not in LQT1 rabbits. The multivariate analyses of APD as a function of two previous CLs (APDn = C + α1CLn−1 + α2CLn−2) showed that α1 (APD restitution slope) is largest and heterogeneous in LQT2 but uniform in LQT1, enhancing APD dispersion under long CLn−1 in LQT2. The α2 (short-term memory) was negative in LQT2 while positive in LQT1, and the spatial pattern of α1 was inversely correlated to α2 in LQT2, which explains why a short-long combination causes a larger APD dispersion in LQT2 but not in LQT1 rabbits. In conclusion, short-long RR pattern increased APD dispersion only in LQT2 rabbits through heterogeneous APD restitution and the short-term memory, underscoring the genotype-specific triggering of arrhythmias in LQT syndrome.
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Affiliation(s)
- Tae Yun Kim
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul Jeng
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - JungMin Hwang
- College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - Zachary Pfeiffer
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Divyang Patel
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Leroy L Cooper
- Biology Department, Vassar College, Poughkeepsie, NY, USA
| | - Konstantinos Kossidas
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Jason Centracchio
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Xuwen Peng
- Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Zhilin Qu
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Bum-Rak Choi
- Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA.
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15
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Xiong L, Liu Y, Zhou M, Wang G, Quan D, Shen C, Shuai W, Kong B, Huang C, Huang H. Targeted ablation of cardiac sympathetic neurons improves ventricular electrical remodelling in a canine model of chronic myocardial infarction. Europace 2019; 20:2036-2044. [PMID: 29860489 DOI: 10.1093/europace/euy090] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/05/2018] [Indexed: 12/25/2022] Open
Abstract
Aims The purpose of this study was to evaluate the cardiac electrophysiologic effects of targeted ablation of cardiac sympathetic neurons (TACSN) in a canine model of chronic myocardial infarction (MI). Methods and results Thirty-eight anaesthetized dogs were randomly assigned into the sham-operated, MI, and MI-TACSN groups, respectively. Myocardial infarction-targeted ablation of cardiac sympathetic neuron was induced by injecting cholera toxin B subunit-saporin compound in the left stellate ganglion (LSG). Five weeks after surgery, the cardiac function, heart rate variability (HRV), ventricular electrophysiological parameters, LSG function and neural activity, serum norepinephrine (NE), nerve growth factor (NGF), and brain natriuretic peptide (BNP) levels were measured. Cardiac sympathetic innervation was determined with immunofluorescence staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). Compared with MI group, TACSN significantly improved HRV, attenuated LSG function and activity, prolonged corrected QT interval, decreased Tpeak-Tend interval, prolonged ventricular effective refractory period (ERP), and action potential duration (APD), decreased the slopes of APD restitution curves, suppressed the APD alternans, increased ventricular fibrillation threshold, and reduced serum NE, NGF, and BNP levels. Moreover, the densities of GAP43 and TH-positive nerve fibres in the infarcted border zone in the MI-TACSN group were lower than those in the MI group. Conclusion Targeted ablation of cardiac sympathetic neuron attenuates sympathetic remodelling and improves ventricular electrical remodelling in the chronic phase of MI. These data suggest that TACSN may be a novel approach to treating ventricular arrhythmias.
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Affiliation(s)
- Liang Xiong
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Yu Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Mingmin Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Guangji Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Dajun Quan
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Caijie Shen
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Wei Shuai
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Bin Kong
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
| | - He Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.,Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China
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16
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Wang L, Morotti S, Tapa S, Francis Stuart SD, Jiang Y, Wang Z, Myles RC, Brack KE, Ng GA, Bers DM, Grandi E, Ripplinger CM. Different paths, same destination: divergent action potential responses produce conserved cardiac fight-or-flight response in mouse and rabbit hearts. J Physiol 2019; 597:3867-3883. [PMID: 31215643 DOI: 10.1113/jp278016] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/17/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Cardiac electrophysiology and Ca2+ handling change rapidly during the fight-or-flight response to meet physiological demands. Despite dramatic differences in cardiac electrophysiology, the cardiac fight-or-flight response is highly conserved across species. In this study, we performed physiological sympathetic nerve stimulation (SNS) while optically mapping cardiac action potentials and intracellular Ca2+ transients in innervated mouse and rabbit hearts. Despite similar heart rate and Ca2+ handling responses between mouse and rabbit hearts, we found notable species differences in spatio-temporal repolarization dynamics during SNS. Species-specific computational models revealed that these electrophysiological differences allowed for enhanced Ca2+ handling (i.e. enhanced inotropy) in each species, suggesting that electrophysiological responses are fine-tuned across species to produce optimal cardiac fight-or-flight responses. ABSTRACT Sympathetic activation of the heart results in positive chronotropy and inotropy, which together rapidly increase cardiac output. The precise mechanisms that produce the electrophysiological and Ca2+ handling changes underlying chronotropic and inotropic responses have been studied in detail in isolated cardiac myocytes. However, few studies have examined the dynamic effects of physiological sympathetic nerve activation on cardiac action potentials (APs) and intracellular Ca2+ transients (CaTs) in the intact heart. Here, we performed bilateral sympathetic nerve stimulation (SNS) in fully innervated, Langendorff-perfused rabbit and mouse hearts. Dual optical mapping with voltage- and Ca2+ -sensitive dyes allowed for analysis of spatio-temporal AP and CaT dynamics. The rabbit heart responded to SNS with a monotonic increase in heart rate (HR), monotonic decreases in AP and CaT duration (APD, CaTD), and a monotonic increase in CaT amplitude. The mouse heart had similar HR and CaT responses; however, a pronounced biphasic APD response occurred, with initial prolongation (50.9 ± 5.1 ms at t = 0 s vs. 60.6 ± 4.1 ms at t = 15 s, P < 0.05) followed by shortening (46.5 ± 9.1 ms at t = 60 s, P = NS vs. t = 0). We determined the biphasic APD response in mouse was partly due to dynamic changes in HR during SNS and was exacerbated by β-adrenergic activation. Simulations with species-specific cardiac models revealed that transient APD prolongation in mouse allowed for greater and more rapid CaT responses, suggesting more rapid increases in contractility; conversely, the rabbit heart requires APD shortening to produce optimal inotropic responses. Thus, while the cardiac fight-or-flight response is highly conserved between species, the underlying mechanisms orchestrating these effects differ significantly.
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Affiliation(s)
- Lianguo Wang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Stefano Morotti
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Srinivas Tapa
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | | | - Yanyan Jiang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Zhen Wang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Rachel C Myles
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Kieran E Brack
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - G André Ng
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Donald M Bers
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Eleonora Grandi
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
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17
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The autonomic nervous system and cardiac arrhythmias: current concepts and emerging therapies. Nat Rev Cardiol 2019; 16:707-726. [DOI: 10.1038/s41569-019-0221-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2019] [Indexed: 12/19/2022]
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18
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Interaction between Endothelin-1 and Left Stellate Ganglion Activation: A Potential Mechanism of Malignant Ventricular Arrhythmia during Myocardial Ischemia. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6508328. [PMID: 31214281 PMCID: PMC6535892 DOI: 10.1155/2019/6508328] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Endothelin-1 (ET-1) is synthesized primarily by endothelial cells. ET-1 administration in vivo enhances the cardiac sympathetic afferent reflex and sympathetic activity. Previous studies have shown that sympathetic hyperactivity promotes malignant ventricular arrhythmia (VA). The aim of this study was to investigate whether ET-1 could activate the left stellate ganglion (LSG) and promote malignant VA. Twelve male beagle dogs who received local microinjections of saline (control, n = 6) and ET-1 into the LSG (n = 6) were included. The ventricular effective refractory period (ERP), LSG function, and LSG activity were measured at different time points. VA was continuously recorded for 1 h after left anterior descending occlusion (LADO), and LSG tissues were then collected for molecular detection. Compared to that of the control group, local ET-1 microinjection significantly decreased the ERP and increased the occurrence of VA. In addition, local microinjection of ET-1 increased the function and activity of the LSG in the normal and ischemic hearts. The expression levels of proinflammatory cytokines and the protein expression of c-fos and nerve growth factor (NGF) in the LSG were also increased. More importantly, endothelin A receptor (ETA-R) expression was found in the LSG, and its signaling was significantly activated in the ET-1 group. LSG activation induced by local ET-1 microinjection aggravates LADO-induced VA. Activated ETA-R signaling and the upregulation of proinflammatory cytokines in the LSG may be responsible for these effects.
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19
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Carnevali L, Statello R, Sgoifo A. Resting Heart Rate Variability Predicts Vulnerability to Pharmacologically-Induced Ventricular Arrhythmias in Male Rats. J Clin Med 2019; 8:jcm8050655. [PMID: 31083474 PMCID: PMC6572182 DOI: 10.3390/jcm8050655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 12/03/2022] Open
Abstract
The electrical stability of the myocardium is dependent on the dynamic balance between sympathetic and parasympathetic influences on the heart, which is reflected by heart rate variability (HRV). Reduced HRV is a proposed predictor of sudden death caused by ventricular tachyarrhythmias in cardiac patients. However, the link between individual differences in HRV and ventricular tachyarrhythmic risk in populations without known pre-existing cardiac conditions is less well explored. In this study we investigated the extent to which individual differences in resting state HRV predict susceptibility to spontaneous and pharmacologically-induced ventricular arrhythmias in healthy rats. Radiotelemetric transmitters were implanted in 42 adult male Wild-type Groningen rats. ECG signals were recorded during 24-h resting conditions and under β-adrenoceptor pharmacological stimulation with isoproterenol and analyzed by means of time- and frequency-domain indexes of HRV. No significant association was found between individual differences in resting measures of HRV and spontaneous incidence of ventricular arrhythmias. However, lower resting values of HRV predicted a higher number of ventricular ectopic beats following β-adrenergic pharmacological stimulation with isoproterenol (0.02 mg/kg). Moreover, after isoproterenol administration, one rat with low resting HRV developed sustained ventricular tachycardia that led to death. The present results might be indicative of the potential utility of HRV measures of resting cardiac autonomic function for the prediction of ventricular arrhythmias, particularly during conditions of strong sympathetic activation, in populations without known cardiac disease.
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Affiliation(s)
- Luca Carnevali
- Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy.
| | - Rosario Statello
- Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy.
| | - Andrea Sgoifo
- Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy.
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20
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Tomek J, Hao G, Tomková M, Lewis A, Carr C, Paterson DJ, Rodriguez B, Bub G, Herring N. β-Adrenergic Receptor Stimulation and Alternans in the Border Zone of a Healed Infarct: An ex vivo Study and Computational Investigation of Arrhythmogenesis. Front Physiol 2019; 10:350. [PMID: 30984029 PMCID: PMC6450465 DOI: 10.3389/fphys.2019.00350] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/14/2019] [Indexed: 12/21/2022] Open
Abstract
Background: Following myocardial infarction (MI), the myocardium is prone to calcium-driven alternans, which typically precedes ventricular tachycardia and fibrillation. MI is also associated with remodeling of the sympathetic innervation in the infarct border zone, although how this influences arrhythmogenesis is controversial. We hypothesize that the border zone is most vulnerable to alternans, that β-adrenergic receptor stimulation can suppresses this, and investigate the consequences in terms of arrhythmogenic mechanisms. Methods and Results: Anterior MI was induced in Sprague-Dawley rats (n = 8) and allowed to heal over 2 months. This resulted in scar formation, significant (p < 0.05) dilation of the left ventricle, and reduction in ejection fraction compared to sham operated rats (n = 4) on 7 T cardiac magnetic resonance imaging. Dual voltage/calcium optical mapping of post-MI Langendorff perfused hearts (using RH-237 and Rhod2) demonstrated that the border zone was significantly more prone to alternans than the surrounding myocardium at longer cycle lengths, predisposing to spatially heterogeneous alternans. β-Adrenergic receptor stimulation with norepinephrine (1 μmol/L) attenuated alternans by 60 [52–65]% [interquartile range] and this was reversed with metoprolol (10 μmol/L, p = 0.008). These results could be reproduced by computer modeling of the border zone based on our knowledge of β-adrenergic receptor signaling pathways and their influence on intracellular calcium handling and ion channels. Simulations also demonstrated that β-adrenergic receptor stimulation in this specific region reduced the formation of conduction block and the probability of premature ventricular activation propagation. Conclusion: While high levels of overall cardiac sympathetic drive are a negative prognostic indicator of mortality following MI and during heart failure, β-adrenergic receptor stimulation in the infarct border zone reduced spatially heterogeneous alternans, and prevented conduction block and propagation of extrasystoles. This may help explain recent clinical imaging studies using meta-iodobenzylguanidine (MIBG) and 11C-meta-hydroxyephedrine positron emission tomography (PET) which demonstrate that border zone denervation is strongly associated with a high risk of future arrhythmia.
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Affiliation(s)
- Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Guoliang Hao
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Markéta Tomková
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Andrew Lewis
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Carolyn Carr
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - David J Paterson
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Gil Bub
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Neil Herring
- Department of Physiology, Anatomy and Genetics, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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21
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Li D, Paterson DJ. Pre-synaptic sympathetic calcium channels, cyclic nucleotide-coupled phosphodiesterases and cardiac excitability. Semin Cell Dev Biol 2019; 94:20-27. [PMID: 30658154 DOI: 10.1016/j.semcdb.2019.01.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/07/2019] [Accepted: 01/14/2019] [Indexed: 12/20/2022]
Abstract
In sympathetic neurons innervating the heart, action potentials activate voltage-gated Ca2+ channels and evoke Ca2+ entry into presynaptic terminals triggering neurotransmitter release. Binding of transmitters to specific receptors stimulates signal transduction pathways that cause changes in cardiac function. The mechanisms contributing to presynaptic Ca2+ dynamics involve regulation of endogenous Ca2+ buffers, in particular the endoplasmic reticulum, mitochondria and cyclic nucleotide targeted pathways. The purpose of this review is to summarize and highlight recent findings about Ca2+ homeostasis in cardiac sympathetic neurons and how modulation of second messengers can drive neurotransmission and affect myocyte excitability in cardiovascular disease. Moreover, we discuss the underlying mechanism of abnormal intracellular Ca2+ homeostasis and signaling in these neurons, and speculate on the role of phosphodiesterases as a therapeutic target to restore normal autonomic transmission in disease states of overactivity.
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Affiliation(s)
- Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
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22
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Investigation of the relationship between two novel electrocardiogram-based sudden cardiac death risk markers and autonomic function. J Electrocardiol 2018; 51:889-894. [PMID: 30177335 DOI: 10.1016/j.jelectrocard.2018.07.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 06/15/2018] [Accepted: 07/18/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Regional Restitution Instability Index (R2I2) and Peak ECG Restitution Slope (PERS) are promising sudden cardiac death (SCD) risk markers. R2I2 and PERS use the standard 12‑lead ECG to measure properties of electrical restitution implicated in ventricular arrhythmogenesis. We investigated the relationship between R2I2, PERS and autonomic function to inform future application of these risk markers. METHODS Blinded, prospective, observational study of 44 patients with ischaemic cardiomyopathy undergoing risk stratification for an ICD. Patients underwent an electrophysiological study for determination of R2I2 and PERS. 24-hour ambulatory ECG monitoring was carried out for determination of time-domain heart rate variability (HRV). RESULTS During median follow up of 22 months, 11 patients experienced ventricular arrhythmia (VA)/SCD. Weak inverse correlation was seen between R2I2 and HRV-i (rho: -0.36, p = 0.02). R2I2 and PERS were significantly higher in patients experiencing VA/SCD than those not (mean ± SEM:1.14 ± 0.11 vs 0.84 ± 0.05, p = 0.01) and (1.73 ± 0.27 vs 1.07 ± 0.08, p = 0.002) respectively. Patients with low HRV-i and high PERS had an incidence rate ratio for VA/SCD 14.5 times that of patients with high HRV-i and low PERS (p = 0.02). CONCLUSION This small study suggests that there is minimal correlation between R2I2, PERS and autonomic function as measured by HRV. Combining PERS with HRV identified patients at particularly high risk of ventricular arrhythmia/SCD. A combined PERS+HRV risk marker may improve SCD risk stratification in patients with ischaemic cardiomyopathy.
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23
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Ng GA, Mistry A, Li X, Schlindwein FS, Nicolson WB. LifeMap: towards the development of a new technology in sudden cardiac death risk stratification for clinical use. Europace 2018; 20:f162-f170. [PMID: 29684162 DOI: 10.1093/europace/euy080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/21/2018] [Indexed: 12/20/2022] Open
Abstract
Sudden cardiac death (SCD) is a major cause of mortality presenting a significant unmet clinical need. Patients at risk of SCD are implanted with implantable cardioverter-defibrillators (ICDs) according to international guidelines based on clinical trial evidence. Implantable cardioverter-defibrillators are not inexpensive and not without problem in terms of inappropriate shocks and infection risk. Also, only a minority of patients implanted with the ICD ever use the device during its battery lifetime highlighting the fact that methods used for SCD risk stratification are inadequate. Better ways of predicting who is at risk of SCD are needed. In addition, there is no effective prevention due to the lack of understanding of the electrical mechanisms underlying SCD. Our group has been investigating the electrophysiological basis of ventricular fibrillation and have successfully applied our preclinical findings to translational studies in patients with ischaemic cardiomyopathy. We have developed two ECG markers which have been shown to be strong predictors of ventricular arrhythmias and SCD. Ongoing clinical studies are being carried out including a multicentre UK study to consolidate the evidence base. They are being incorporated into the technology, LifeMap, with the aim to develop a successful clinical tool for the assessment of SCD risk. We hereby present the scientific data leading to the technology and the development to date. The information provided here was presented at the European Heart Rhythm Association (EHRA) Europace/Cardiostim conference at which LifeMap won the EHRA Inventors Award 2016.
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Affiliation(s)
- Ghulam André Ng
- Cardiology Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE39QP, UK.,NIHR Leicester Biomedical Research Centre, Leicester, UK.,Department of Cardiology, Glenfield Hospital, Leicester, UK
| | - Amar Mistry
- Cardiology Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE39QP, UK.,Department of Cardiology, Glenfield Hospital, Leicester, UK
| | - Xin Li
- Cardiology Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE39QP, UK.,Department of Engineering, University of Leicester, UK
| | - Fernando S Schlindwein
- NIHR Leicester Biomedical Research Centre, Leicester, UK.,Department of Engineering, University of Leicester, UK
| | - William B Nicolson
- Cardiology Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE39QP, UK.,NIHR Leicester Biomedical Research Centre, Leicester, UK.,Department of Cardiology, Glenfield Hospital, Leicester, UK
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24
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Yeo JM, Tse V, Kung J, Lin HY, Lee YT, Kwan J, Yan BP, Tse G. Isolated heart models for studying cardiac electrophysiology: a historical perspective and recent advances. J Basic Clin Physiol Pharmacol 2018; 28:191-200. [PMID: 28063261 DOI: 10.1515/jbcpp-2016-0110] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/12/2016] [Indexed: 01/25/2023]
Abstract
Experimental models used in cardiovascular research range from cellular to whole heart preparations. Isolated whole hearts show higher levels of structural and functional integration than lower level models such as tissues or cellular fragments. Cardiovascular diseases are multi-factorial problems that are dependent on highly organized structures rather than on molecular or cellular components alone. This article first provides a general introduction on the animal models of cardiovascular diseases. It is followed by a detailed overview and a historical perspective of the different isolated heart systems with a particular focus on the Langendorff perfusion method for the study of cardiac arrhythmias. The choice of species, perfusion method, and perfusate composition are discussed in further detail with particular considerations of the theoretical and practical aspects of experimental settings.
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Affiliation(s)
- Jie Ming Yeo
- School of Medicine, Imperial College London, London
| | - Vivian Tse
- Department of Physiology, McGill University, Montreal, Quebec
| | - Judy Kung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, P.R
| | - Hiu Yu Lin
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, P.R
| | - Yee Ting Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, P.R
| | - Joseph Kwan
- Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, P.R
| | - Bryan P Yan
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne
| | - Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, P.R
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25
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Arrhythmogenic drugs can amplify spatial heterogeneities in the electrical restitution in perfused guinea-pig heart: An evidence from assessments of monophasic action potential durations and JT intervals. PLoS One 2018; 13:e0191514. [PMID: 29352276 PMCID: PMC5774816 DOI: 10.1371/journal.pone.0191514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/06/2018] [Indexed: 01/01/2023] Open
Abstract
Non-uniform shortening of the action potential duration (APD90) in different myocardial regions upon heart rate acceleration can set abnormal repolarization gradients and promote arrhythmia. This study examined whether spatial heterogeneities in APD90 restitution can be amplified by drugs with clinically proved proarrhythmic potential (dofetilide, quinidine, procainamide, and flecainide) and, if so, whether these effects can translate to the appropriate changes of the ECG metrics of ventricular repolarization, such as JT intervals. In isolated, perfused guinea-pig heart preparations, monophasic action potentials and volume-conducted ECG were recorded at progressively increased pacing rates. The APD90 measured at distinct ventricular sites, as well as the JTpeak and JTend values were plotted as a function of preceding diastolic interval, and the maximum slopes of the restitution curves were determined at baseline and upon drug administration. Dofetilide, quinidine, and procainamide reverse rate-dependently prolonged APD90 and steepened the restitution curve, with effects being greater at the endocardium than epicardium, and in the right ventricular (RV) vs. the left ventricular (LV) chamber. The restitution slope was increased to a greater extent for the JTend vs. the JTpeak interval. In contrast, flecainide reduced the APD90 restitution slope at LV epicardium without producing effect at LV endocardium and RV epicardium, and reduced the JTpeak restitution slope without changing the JTend restitution. Nevertheless, with all agents, these effects translated to the amplified epicardial-to-endocardial and the LV-to-RV non-uniformities in APD90 restitution, paralleled by the increased JTend vs. JTpeak difference in the restitution slope. In summary, these findings suggest that arrhythmic drug profiles are partly attributable to the accentuated regional heterogeneities in APD90 restitution, which can be indirectly determined through ECG assessments of the JTend vs. JTpeak dynamics at variable pacing rates.
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26
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Wang M, Li S, Zhou X, Huang B, Zhou L, Li X, Meng G, Yuan S, Wang Y, Wang Z, Wang S, Yu L, Jiang H. Increased inflammation promotes ventricular arrhythmia through aggravating left stellate ganglion remodeling in a canine ischemia model. Int J Cardiol 2017; 248:286-293. [DOI: 10.1016/j.ijcard.2017.08.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/29/2017] [Accepted: 08/04/2017] [Indexed: 12/21/2022]
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27
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Jamali HK, Waqar F, Gerson MC. Cardiac autonomic innervation. J Nucl Cardiol 2017; 24:1558-1570. [PMID: 27844333 DOI: 10.1007/s12350-016-0725-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 10/25/2016] [Indexed: 10/20/2022]
Abstract
The autonomic nervous system plays a key role in regulating changes in the cardiovascular system and its adaptation to various human body functions. The sympathetic arm of the autonomic nervous system is associated with the fight and flight response, while the parasympathetic division is responsible for the restorative effects on heart rate, blood pressure, and contractility. Disorders involving these two divisions can lead to, and are seen as, a manifestation of most common cardiovascular disorders. Over the last few decades, extensive research has been performed establishing imaging techniques to quantify the autonomic dysfunction associated with various cardiovascular disorders. Additionally, several techniques have been tested with variable success in modulating the cardiac autonomic nervous system as treatment for these disorders. In this review, we summarize basic anatomy, physiology, and pathophysiology of the cardiac autonomic nervous system including adrenergic receptors. We have also discussed several imaging modalities available to aid in diagnosis of cardiac autonomic dysfunction and autonomic modulation techniques, including pharmacologic and device-based therapies, that have been or are being tested currently.
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Affiliation(s)
- Hina K Jamali
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, P.O. Box 670542, Cincinnati, OH, USA
| | - Fahad Waqar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, P.O. Box 670542, Cincinnati, OH, USA
| | - Myron C Gerson
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, P.O. Box 670542, Cincinnati, OH, USA.
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28
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Ng GA. Feasibility of selection of antiarrhythmic drug treatment on the basis of arrhythmogenic mechanism — Relevance of electrical restitution, wavebreak and rotors. Pharmacol Ther 2017; 176:1-12. [DOI: 10.1016/j.pharmthera.2016.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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29
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Effect of Thoracic Epidural Anesthesia on Ventricular Excitability in a Porcine Model. Anesthesiology 2017; 126:1096-1106. [PMID: 28358748 DOI: 10.1097/aln.0000000000001613] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Imbalances in the autonomic nervous system, namely, excessive sympathoexcitation, contribute to ventricular tachyarrhythmias. While thoracic epidural anesthesia clinically suppresses ventricular tachyarrhythmias, its effects on global and regional ventricular electrophysiology and electrical wave stability have not been fully characterized. The authors hypothesized that thoracic epidural anesthesia attenuates myocardial excitability and the proarrhythmic effects of sympathetic hyperactivity. METHODS Yorkshire pigs (n = 15) had an epidural catheter inserted (T1 to T4) and a 56-electrode sock placed on the heart. Myocardial excitability was measured by activation recovery interval, dispersion of repolarization, and action potential duration restitution at baseline and during programed ventricular extrastimulation or left stellate ganglion stimulation, before and 30 min after thoracic epidural anesthesia (0.25% bupivacaine). RESULTS After thoracic epidural anesthesia infusion, there was no change in baseline activation recovery interval or dispersion of repolarization. During programmed ventricular extrastimulation, thoracic epidural anesthesia decreased the maximum slope of ventricular electrical restitution (0.70 ± 0.24 vs. 0.89 ± 0.24; P = 0.021) reflecting improved electrical wave stability. Thoracic epidural anesthesia also reduced myocardial excitability during left stellate ganglion stimulation-induced sympathoexcitation through attenuated shortening of activation recovery interval (-7 ± 4% vs. -4 ± 3%; P = 0.001), suppression of the increase in dispersion of repolarization (313 ± 293% vs. 185 ± 234%; P = 0.029), and reduction in sympathovagal imbalance as measured by heart rate variability. CONCLUSIONS Our study describes the electrophysiologic mechanisms underlying antiarrhythmic effects of thoracic epidural anesthesia during sympathetic hyperactivity. Thoracic epidural anesthesia attenuates ventricular myocardial excitability and induces electrical wave stability through its effects on activation recovery interval, dispersion of repolarization, and the action potential duration restitution slope.
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30
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Osadchii OE. Role of abnormal repolarization in the mechanism of cardiac arrhythmia. Acta Physiol (Oxf) 2017; 220 Suppl 712:1-71. [PMID: 28707396 DOI: 10.1111/apha.12902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In cardiac patients, life-threatening tachyarrhythmia is often precipitated by abnormal changes in ventricular repolarization and refractoriness. Repolarization abnormalities typically evolve as a consequence of impaired function of outward K+ currents in cardiac myocytes, which may be caused by genetic defects or result from various acquired pathophysiological conditions, including electrical remodelling in cardiac disease, ion channel modulation by clinically used pharmacological agents, and systemic electrolyte disorders seen in heart failure, such as hypokalaemia. Cardiac electrical instability attributed to abnormal repolarization relies on the complex interplay between a provocative arrhythmic trigger and vulnerable arrhythmic substrate, with a central role played by the excessive prolongation of ventricular action potential duration, impaired intracellular Ca2+ handling, and slowed impulse conduction. This review outlines the electrical activity of ventricular myocytes in normal conditions and cardiac disease, describes classical electrophysiological mechanisms of cardiac arrhythmia, and provides an update on repolarization-related surrogates currently used to assess arrhythmic propensity, including spatial dispersion of repolarization, activation-repolarization coupling, electrical restitution, TRIaD (triangulation, reverse use dependence, instability, and dispersion), and the electromechanical window. This is followed by a discussion of the mechanisms that account for the dependence of arrhythmic vulnerability on the location of the ventricular pacing site. Finally, the review clarifies the electrophysiological basis for cardiac arrhythmia produced by hypokalaemia, and gives insight into the clinical importance and pathophysiology of drug-induced arrhythmia, with particular focus on class Ia (quinidine, procainamide) and Ic (flecainide) Na+ channel blockers, and class III antiarrhythmic agents that block the delayed rectifier K+ channel (dofetilide).
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Affiliation(s)
- O. E. Osadchii
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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31
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Yu L, Wang M, Hu D, Huang B, Zhou L, Zhou X, Wang Z, Wang S, Jiang H. Blocking the Nav1.8 channel in the left stellate ganglion suppresses ventricular arrhythmia induced by acute ischemia in a canine model. Sci Rep 2017; 7:534. [PMID: 28373696 PMCID: PMC5428783 DOI: 10.1038/s41598-017-00642-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 03/07/2017] [Indexed: 01/01/2023] Open
Abstract
Left stellate ganglion (LSG) hyperactivity promotes ischemia induced ventricular arrhythmia (VA). Blocking the Nav1.8 channel decreases neuron activity. Therefore, the present study aimed to investigate whether blocking the Nav1.8 channel with its specific blocker A-803467 in the LSG reduces sympathetic activity and exerts anti-arrhythmic effects. Forty canines were divided into dimethylsulfoxide (DMSO) group and 10 mM, 15 mM, and 20 mM A-803467 groups. A volume of 0.1 ml of A-803467 or DMSO was injected into the LSG. The ventricular electrophysiological parameters, LSG function were measured before and 30 min after the injection. VA was assessed for 60 min after ischemia and then LSG tissues were collected for molecular biological experiments. Compared with DMSO, concentration-dependent prolonged action potential duration and effective refractory period, decreased LSG function were identified after A-803467 treatment. Moreover, the severity of ischemia induced VA was decreased in A-803467 groups. Furthermore, decreased nerve growth factor, decreased c-fos and increased sympathetic neuron apoptosis were found in the LSG after A-803467 injection. In conclusion, blocking the Nav1.8 channel could significantly attenuate ischemia-induced VA, primarily by suppressing LSG activity.
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Affiliation(s)
- Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Menglong Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Dan Hu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China.,Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, New York, 13501-1787, USA
| | - Bing Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Liping Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Xiaoya Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Zhuo Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Songyun Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Hong Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Wuhan University, Hubei Key Laboratory of Cardiology, Wuhan, China.
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32
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Ang R, Abramowitz J, Birnbaumer L, Gourine AV, Tinker A. The role of GαO-mediated signaling in the rostral ventrolateral medulla oblongata in cardiovascular reflexes and control of cardiac ventricular excitability. Physiol Rep 2017; 4:4/15/e12860. [PMID: 27528004 PMCID: PMC4985541 DOI: 10.14814/phy2.12860] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/20/2016] [Indexed: 12/02/2022] Open
Abstract
The heart is controlled by the sympathetic and parasympathetic limbs of the autonomic nervous system with inhibitory signaling mechanisms recruited in both limbs. The aim of this study was to determine the role of inhibitory heterotrimeric G proteins in the central nervous mechanisms underlying autonomic control of the heart and its potential role in arrhythmogenesis. Mice with conditional deletion of the inhibitory heterotrimeric G protein GαO in the presympathetic area of the rostral ventral lateral medulla (RVLM) were generated to determine the role of GαO‐mediated signalling in autonomic control and electrophysiological properties of the heart. GαO deletion within the RVLM was not associated with changes in heart rate (HR) or the arterial blood pressure at rest (home cage, normal behavior). However, exposure to stressful conditions (novel environment, hypoxia, or hypercapnia) in these mice was associated with abnormal HR responses and an increased baroreflex gain when assessed under urethane anesthesia. This was associated with shortening of the ventricular effective refractory period. This phenotype was reversed by systemic beta‐adrenoceptor blockade, suggesting that GαO depletion in the RVLM increases central sympathetic drive. The data obtained support the hypothesis that GαO‐mediated signaling within the presympathetic circuits of the RVLM contributes to the autonomic control of the heart. GαO deficiency in the RVLM has a significant impact on cardiovascular responses to stress, cardiovascular reflexes and electrical properties of the heart.
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Affiliation(s)
- Richard Ang
- William Harvey Heart Centre, Barts & The London School of Medicine and Dentistry, London, UK Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Joel Abramowitz
- Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Lutz Birnbaumer
- Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Alexander V Gourine
- William Harvey Heart Centre, Barts & The London School of Medicine and Dentistry, London, UK
| | - Andrew Tinker
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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Yamada S, Lo LW, Chou YH, Lin WL, Chang SL, Lin YJ, Liu SH, Cheng WH, Tsai TY, Chen SA. Beneficial Effect of Renal Denervation on Ventricular Premature Complex Induced Cardiomyopathy. J Am Heart Assoc 2017; 6:JAHA.116.004479. [PMID: 28255076 PMCID: PMC5523999 DOI: 10.1161/jaha.116.004479] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background Frequent ventricular premature complexes (VPCs) can lead to the development of dilated cardiomyopathy and sudden cardiac death. Renal artery sympathetic denervation (RDN) may protect the heart from remodeling. This study aimed to investigate the effect of frequent VPCs on structural and electrical properties and whether RDN can protect the heart from remodeling. Methods and Results Eighteen rabbits were randomized to control (n=6), VPC (n=6), and VPC‐RDN (n=6) groups. Surgical and chemical RDNs were approached through bilateral retroperitoneal flank incisions in the VPC‐RDN group. Pacemakers were implanted to the left ventricular apex to produce 50% VPC burden for 5 weeks in the VPC and VPC‐RDN groups. In addition, ventricular myocardium was harvested for western blot and trichrome stain. Echocardiographic results showed left ventricular enlargement after 5‐week pacing in the VPC group, but not in the VPC‐RDN group, when compared to baseline. In biventricles, ion channel protein expressions of Nav1.5, Cav1.2, Kir2.1, and SERCA2 were similar among 3 groups. However, the degree of biventricular fibrosis was extensive in the VPC group, compared to the control and VPC‐RDN groups. Importantly, ventricular fibrillation inducibility was higher in the VPC group (41%) when comparing to the control (13%; P<0.05) and VPC‐RDN groups (13%; P<0.05), respectively. Conclusions Frequent VPCs are associated with the development of cardiac structural remodeling and high ventricular fibrillation inducibility. RDN prevents cardiac remodeling and the occurrence of ventricular arrhythmia through antifibrosis.
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Affiliation(s)
- Shinya Yamada
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Li-Wei Lo
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C. .,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Hui Chou
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C
| | - Wei-Lun Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Shih-Lin Chang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Yenn-Jiang Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Shin-Huei Liu
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Wen-Han Cheng
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Tsung-Ying Tsai
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C.,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Shih-Ann Chen
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan, R.O.C. .,Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
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Finlay M, Harmer SC, Tinker A. The control of cardiac ventricular excitability by autonomic pathways. Pharmacol Ther 2017; 174:97-111. [PMID: 28223225 DOI: 10.1016/j.pharmthera.2017.02.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Central to the genesis of ventricular cardiac arrhythmia are variations in determinants of excitability. These involve individual ionic channels and transporters in cardiac myocytes but also tissue factors such as variable conduction of the excitation wave, fibrosis and source-sink mismatch. It is also known that in certain diseases and particularly the channelopathies critical events occur with specific stressors. For example, in hereditary long QT syndrome due to mutations in KCNQ1 arrhythmic episodes are provoked by exercise and in particular swimming. Thus not only is the static substrate important but also how this is modified by dynamic signalling events associated with common physiological responses. In this review, we examine the regulation of ventricular excitability by signalling pathways from a cellular and tissue perspective in an effort to identify key processes, effectors and potential therapeutic approaches. We specifically focus on the autonomic nervous system and related signalling pathways.
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Affiliation(s)
- Malcolm Finlay
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK
| | - Stephen C Harmer
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK
| | - Andrew Tinker
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK.
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35
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Kalla M, Herring N, Paterson DJ. Cardiac sympatho-vagal balance and ventricular arrhythmia. Auton Neurosci 2016; 199:29-37. [PMID: 27590099 PMCID: PMC5334443 DOI: 10.1016/j.autneu.2016.08.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 12/11/2022]
Abstract
A hallmark of cardiovascular disease is cardiac autonomic dysregulation. The phenotype of impaired parasympathetic responsiveness and sympathetic hyperactivity in experimental animal models is also well documented in large scale human studies in the setting of heart failure and myocardial infarction, and is predictive of morbidity and mortality. Despite advances in emergency revascularisation strategies for myocardial infarction, device therapy for heart failure and secondary prevention pharmacotherapies, mortality from malignant ventricular arrhythmia remains high. Patients at highest risk or those with haemodynamically significant ventricular arrhythmia can be treated with catheter ablation and implantable cardioverter defibrillators, but the morbidity and reduction in quality of life due to the burden of ventricular arrhythmia and shock therapy persists. Therefore, future therapies must aim to target the underlying pathophysiology that contributes to the generation of ventricular arrhythmia. This review explores recent advances in mechanistic research in both limbs of the autonomic nervous system and potential avenues for translation into clinical therapy. In addition, we also discuss the relationship of these findings in the context of the reported efficacy of current neuromodulatory strategies in the management of ventricular arrhythmia. We review advances in mechanistic research in the cardiac autonomic nervous system. This is discussed in relation to neuromodulatory therapy for ventricular arrhythmia. Neuromodulation therapies can influence both neurotransmitters and co-transmitters. This may therefore improve on conventional medical treatment.
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Affiliation(s)
| | - Neil Herring
- Corresponding author at: Burdon Sanderson Cardiac Science Centre, Dept. of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, OX13PT, UK.Burdon Sanderson Cardiac Science CentreDept. of Physiology, Anatomy and GeneticsUniversity of OxfordParks RoadOX13PTUK
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Coote JH, Chauhan RA. The sympathetic innervation of the heart: Important new insights. Auton Neurosci 2016; 199:17-23. [PMID: 27568995 DOI: 10.1016/j.autneu.2016.08.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 08/19/2016] [Accepted: 08/20/2016] [Indexed: 01/20/2023]
Abstract
Autonomic control of the heart has a significant influence over development of life threatening arrhythmias that can lead to sudden cardiac death. Sympathetic activity is known to be upregulated during these conditions and hence the sympathetic nerves present a target for treatment. However, a better understanding of the anatomy and physiology of cardiac sympathetic nerves is required for the progression of clinical interventions. This review explores the organization of the cardiac sympathetic nerves, from the preganglionic origin to the postganglionic innervations, and provides an overview of literature surrounding anti-arrhythmic therapies including thoracic sympathectomy and dorsal spinal cord stimulation. Several features of the innervation are clear. The cardiac nerves differentially supply the nodal and myocardial tissue of the heart and are dependent on activity generated in spinal neurones in the upper thoracic cord which project to synapse with ganglion cells in the stellate complex on each side. Networks of spinal interneurones determine the pattern of activity. Groups of spinal neurones selectively target specific regions of the heart but whether they exhibit a functional selectivity has still to be elucidated. Electrical or ischemic signals can lead to remodeling of nerves in the heart or ganglia. Surgical and electrical methods are proving to be clinically beneficial in reducing atrial and ventricular arrhythmias, heart failure and severe cardiac pain. This is a rapidly developing area and we need more basic understanding of how these methods work to ensure safety and reduction of side effects.
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Affiliation(s)
- J H Coote
- Cardiovascular Sciences, Glenfield Hospital, University of Leicester, UK; School of Clinical and Experimental Medicine, University of Birmingham, UK.
| | - R A Chauhan
- Cardiovascular Sciences, Glenfield Hospital, University of Leicester, UK
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37
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Ng GA. Neuro-cardiac interaction in malignant ventricular arrhythmia and sudden cardiac death. Auton Neurosci 2016; 199:66-79. [DOI: 10.1016/j.autneu.2016.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 07/02/2016] [Accepted: 07/04/2016] [Indexed: 12/30/2022]
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Negroni JA, Morotti S, Lascano EC, Gomes AV, Grandi E, Puglisi JL, Bers DM. β-adrenergic effects on cardiac myofilaments and contraction in an integrated rabbit ventricular myocyte model. J Mol Cell Cardiol 2015; 81:162-75. [PMID: 25724724 DOI: 10.1016/j.yjmcc.2015.02.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/10/2015] [Accepted: 02/17/2015] [Indexed: 12/21/2022]
Abstract
A five-state model of myofilament contraction was integrated into a well-established rabbit ventricular myocyte model of ion channels, Ca(2+) transporters and kinase signaling to analyze the relative contribution of different phosphorylation targets to the overall mechanical response driven by β-adrenergic stimulation (β-AS). β-AS effect on sarcoplasmic reticulum Ca(2+) handling, Ca(2+), K(+) and Cl(-) currents, and Na(+)/K(+)-ATPase properties was included based on experimental data. The inotropic effect on the myofilaments was represented as reduced myofilament Ca(2+) sensitivity (XBCa) and titin stiffness, and increased cross-bridge (XB) cycling rate (XBcy). Assuming independent roles of XBCa and XBcy, the model reproduced experimental β-AS responses on action potentials and Ca(2+) transient amplitude and kinetics. It also replicated the behavior of force-Ca(2+), release-restretch, length-step, stiffness-frequency and force-velocity relationships, and increased force and shortening in isometric and isotonic twitch contractions. The β-AS effect was then switched off from individual targets to analyze their relative impact on contractility. Preventing β-AS effects on L-type Ca(2+) channels or phospholamban limited Ca(2+) transients and contractile responses in parallel, while blocking phospholemman and K(+) channel (IKs) effects enhanced Ca(2+) and inotropy. Removal of β-AS effects from XBCa enhanced contractile force while decreasing peak Ca(2+) (due to greater Ca(2+) buffering), but had less effect on shortening. Conversely, preventing β-AS effects on XBcy preserved Ca(2+) transient effects, but blunted inotropy (both isometric force and especially shortening). Removal of titin effects had little impact on contraction. Finally, exclusion of β-AS from XBCa and XBcy while preserving effects on other targets resulted in preserved peak isometric force response (with slower kinetics) but nearly abolished enhanced shortening. β-AS effects on XBCa and XBcy have greater impact on isometric and isotonic contraction, respectively.
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Affiliation(s)
- Jorge A Negroni
- Department of Comparative, Cellular and Molecular Biology, Universidad Favaloro, Buenos Aires, Argentina.
| | - Stefano Morotti
- Department of Pharmacology, University of California Davis, CA, USA
| | - Elena C Lascano
- Department of Comparative, Cellular and Molecular Biology, Universidad Favaloro, Buenos Aires, Argentina
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology and Behavior, University of California Davis, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, CA, USA
| | - José L Puglisi
- Department of Pharmacology, University of California Davis, CA, USA
| | - Donald M Bers
- Department of Pharmacology, University of California Davis, CA, USA.
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Renal sympathetic denervation for treatment of ventricular arrhythmias: a review on current experimental and clinical findings. Clin Res Cardiol 2015; 104:535-43. [PMID: 25596725 DOI: 10.1007/s00392-015-0812-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/12/2015] [Indexed: 01/09/2023]
Abstract
Ventricular arrhythmias (VAs) remain the major cause of mortality and sudden cardiac death (SCD) in almost all forms of heart disease. Despite so many therapeutic advances, such as pharmacological therapies, catheter ablation, and arrhythmia surgery, management of VAs remains a great challenge for cardiologists. Evidence from histological studies and from direct nerve activity recordings have suggested that increased sympathetic nerve density and activity contribute to the generation of VAs and SCD. It is well known that renal sympathetic nerve (RSN), either afferent component or efferent component, plays an important role in modulation of central sympathetic activity. We have recently shown that RSN activation by electrical stimulation significantly increases cardiac and systemic sympathetic activity and promotes the incidence of acute ischemia-induced VAs, suggesting RSN has a role in the development of VAs. Initial experience of RSN denervation (RDN) in patients with resistant hypertension showed that this novel and minimally invasive device-based approach significantly reduced not only kidney but also whole-body norepinephrine spillover. In addition, experimental studies find that left stellate ganglion nerve activity is significantly decreased after RDN. Based on these observations, it is reasonable to conclude that RDN may be an effective therapy for the management of VAs. Indeed, RDN has provided a protection against VAs in both animal models and patients. In this article, we review the role of the RSN in the generation of VAs and SCD and the role of RDN as a potential treatment strategy for VAs and SCD.
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Huang J, Qian J, Yao W, Wang N, Zhang Z, Cao C, Song B, Zhang Z. Vagus nerve stimulation reverses ventricular electrophysiological changes induced by hypersympathetic nerve activity. Exp Physiol 2014; 100:239-48. [PMID: 25720663 DOI: 10.1113/expphysiol.2014.082842] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 10/24/2014] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Previous studies have shown that hypersympathetic nerve activity results in ventricular electrophysiological changes and facilitates the occurrence of ventricular arrhythmias. Vagus nerve stimulation has shown therapeutic potential for myocardial infarction-induced ventricular arrhythmias. However, the actions of vagus nerve stimulation on hypersympathetic nerve activity-induced ventricular electrophysiological changes are still unknown. What is the main finding and its importance? We show that vagus nerve stimulation is able to reverse hypersympathetic nerve activity-induced ventricular electrophysiological changes and suppress the occurrence of ventricular fibrillation. These findings further suggest that vagus nerve stimulation may be an effective treatment option for ventricular arrhythmias, especially in patients with myocardial infarction or heart failure. Vagus nerve stimulation (VNS) has shown therapeutic potential for myocardial infarction-induced ventricular arrhythmias. This study aimed to investigate the effects of VNS on ventricular electrophysiological changes induced by hypersympathetic nerve activity. Seventeen open-chest dogs were subjected to left stellate ganglion stimulation (LSGS) for 4 h to simulate hypersympathetic tone. All animals were randomly assigned to the VNS group (n = 9) or the control group (n = 8). In the VNS group, VNS was performed at the voltage causing a 10% decrease in heart rate for hours 3-4 during 4 h of LSGS. During the first 2 h of LSGS, the ventricular effective refractory period (ERP) and action potential duration (APD) were both progressively and significantly decreased; the spatial dispersion of ERP, maximal slope of the restitution curve and pacing cycle length of APD alternans were all increased. With LSGS + VNS during the next 2 h, there was a significant return of all the altered electrophysiological parameters towards baseline levels. In the eight control dogs that received 4 h of LSGS without VNS, all the parameters changed progressively, but without any reversals. The ventricular fibrillation threshold was higher in the VNS group than in the control group (17.3 ± 3.4 versus 11.3 ± 3.8 V, P < 0.05). The present study demonstrated that VNS was able to reverse LSGS-induced ventricular electrophysiological changes and suppress the occurrence of ventricular fibrillation.
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Affiliation(s)
- Jie Huang
- Department of Cardiology, Suizhou Hospital, Hubei University of Medicine, Suizhou City, Hubei Province, PR China
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Fossa AA, Zhou M, Robinson A, Purkayastha J, Martin P. Use of ECG restitution (beat-to-beat QT-TQ interval analysis) to assess arrhythmogenic risk of QTc prolongation with guanfacine. Ann Noninvasive Electrocardiol 2014; 19:582-94. [PMID: 25200912 DOI: 10.1111/anec.12202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Guanfacine (Intuniv) is a centrally active alpha-2A adrenergic agonist for the new indication of attention-deficit/hyperactivity disorder. QTc (QTcF and QTcNi) was prolonged at both therapeutic (4 mg) and supratherapeutic (8 mg) doses of a thorough QT study even though guanfacine has had a safe clinical history of over 3 million prescriptions for the treatment of hypertension. In an attempt to understand this disparity, retrospective evaluation of the continuous ECG data utilized dynamic beat-to-beat and ECG restitution analyses was performed. METHODS Sixty healthy subjects using 24-hour Holters were examined in a 3-arm, placebo- and positive-controlled, double-blind crossover study for effects on beat-to-beat QT, TQ, and RR intervals. RESULTS ECG restitution analyses indicated that, at all time points, a disproportionate effect to increase the TQ interval (rest) occurred more in relationship to each QT interval lengthening resulting in a placebo-adjusted reduced QT/TQ ratio of 21% after 4 mg and 31% after 8 mg (both antiarrhythmic responses). Additionally, the percentage of time and magnitude of stress on the heart, as measured by the upper limits of the QT/TQ ratio, were reduced with guanfacine by 22% to 24%. In contrast to guanfacine, moxifloxacin did not show a significant improvement in any restitution parameters but reflected a trend toward proarrhythmia with an increase in the QT/TQ ratio of up to 11%. CONCLUSION These results indicate that guanfacine causes a stabilizing effect on cardiac restitution that helps reconcile the clinical evidence for a lack of arrhythmia liability despite apparent increases in typical QT/QTc prolongation measures.
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Huang B, Yu L, He B, Lu Z, Wang S, He W, Yang K, Liao K, Zhang L, Jiang H. Renal sympathetic denervation modulates ventricular electrophysiology and has a protective effect on ischaemia-induced ventricular arrhythmia. Exp Physiol 2014; 99:1467-77. [PMID: 25172887 DOI: 10.1113/expphysiol.2014.082057] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recently, a beneficial effect of renal sympathetic denervation (RSD) has been seen in patients with ventricular electrical storm. However, the effect of RSD on ventricular electrophysiology remains unclear. Thirty-three mongrel dogs were included in the present study. Renal sympathetic denervation was performed by radiofrequency ablation of the adventitial surface of the renal artery. In group 1 (n = 8), programmed stimulation was performed before and after RSD to determine the ventricular effective refractory period (ERP) and action potential duration (APD) restitution properties. The same parameters were measured in five other animals that underwent sham RSD to serve as controls. In group 2 (n = 10), acute myocardial ischaemia (AMI) was induced by ligating the proximal left anterior descending coronary artery after the performance of RSD, and the incidence of ventricular arrhythmia (VA) was calculated during 1 h of recording. In another 10 dogs (group 3), AMI was induced and VA was measured with sham RSD. In group 1, RSD significantly prolonged ventricular ERP and APD, reduced the maximal slope (Smax) of the restitution curve and suppressed APD alternans at each site. Renal sympathetic denervation also significantly decreased the spatial dispersion of ERP, APD and Smax. In the five control animals, no significant electrophysiological change was detected after sham RSD. The occurrence of spontaneous VA during 1 h of AMI in group 2 was significantly lower than that in group 3. These data suggest that RSD stabilizes ventricular electrophysiological properties in normal hearts and reduces the occurrence of VA in hearts experiencing AMI.
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Affiliation(s)
- Bing Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Lilei Yu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Bo He
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Zhibing Lu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Songyun Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Wenbo He
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Kang Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Kai Liao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Ling Zhang
- Arrhythmia Research Laboratory, First Affiliated Hospital of Xinjiang Medical University, Urumqi, PR China
| | - Hong Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
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Nicolson WB, McCann GP, Smith MI, Sandilands AJ, Stafford PJ, Schlindwein FS, Samani NJ, Ng GA. Prospective evaluation of two novel ECG-based restitution biomarkers for prediction of sudden cardiac death risk in ischaemic cardiomyopathy. Heart 2014; 100:1878-85. [DOI: 10.1136/heartjnl-2014-305672] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Ashton JL, Paton JFR, Trew ML, LeGrice IJ, Smaill BH. A working heart-brainstem preparation of the rat for the study of reflex mediated autonomic influences on atrial arrhythmia development. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:3785-8. [PMID: 24110555 DOI: 10.1109/embc.2013.6610368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vagal nerve activity has been shown to play a role in the formation and maintenance of atrial fibrillation (AF). Nerves on the atria are now increasingly being targeted using ablation-based therapies for the treatment of paroxysmal AF. In vivo, changes in vagal activity are part of an integrated autonomic profile that invariably involves accompanying modulations in sympathetic activity. To date, it has not been possible to replicate endogenous profiles of autonomic activity with the experimental set-ups used to study the effects of vagal stimulation on AF development. In this paper, we describe an experimental set-up using an in situ preparation that addresses these challenges for the first time. A high resolution surface electrode array has been used to make recordings of atrial electrograms during baroreflex activation from a preparation with intact innervation from brainstem to heart. This provides a novel framework for relating reflex-mediated autonomic activity to altered regional impulse propagation and electrical rhythm in the atria.
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Abstract
NEW FINDINGS What is the topic of this review? This article addresses the relationship between vagus nerve activity and malignant ventricular arrhythmias. It focuses on the clinical association of an impaired vagal tone in cardiac disease states with high mortality from sudden cardiac death and the potential underlying mechanisms. What advances does it highlight? The article summarizes the mounting evidence that vagal innervation in the cardiac ventricle plays a key direct role in the prevention of the initiation of ventricular fibrillation. Data are presented on the role that nitric oxide plays in mediating the effects of vagal protection against ventricular fibrillation, supporting the notion that a separate non-muscarinic, nitrergic population of vagal neurons is responsible for this protection. Sudden cardiac death remains a significant unresolved clinical problem, with many of the deaths being due to malignant ventricular arrhythmias. Markers of abnormal autonomic function have been shown to be strong prognostic predictors, highlighting the important relationship between reduced vagal tone and malignant ventricular arrhythmias, such as ventricular fibrillation, in cardiac patients. Exploring the mechanisms underlying the autonomic modulation of ventricular fibrillation, my group has shown that vagus nerve stimulation protects against ventricular fibrillation in the innervated isolated heart preparation. We have provided direct evidence that nitric oxide is released in the ventricle with cervical vagus nerve stimulation and NO mediates the antifibrillatory actions of vagus nerve stimulation in the ventricle. Classical physiology teaches that vagal postganglionic nerves modulate the heart via acetylcholine acting at muscarinic receptors and, dogmatically, that there is little vagal effect in the ventricle, as innervation was believed to be sparse. Mounting evidence from many species now supports the presence of a rich vagal innervation in the ventricle. Data from my group showing that the protective actions of vagus nerve stimulation against ventricular fibrillation and NO release are preserved in the presence of muscarinic block support the notion that a population of nitrergic neurons could be responsible. This potentially exploitable downstream pathway together with the availability of vagus nerve stimulators make it an exciting time to investigate the development of an effective strategy of vagal protection against ventricular fibrillation in the clinical setting.
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Affiliation(s)
- G André Ng
- * Department of Cardiovascular Sciences, Cardiology group, University of Leicester, Clinical Sciences Wing, Glenfield Hospital, Leicester LE3 9QP, UK.
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The Lambeth Conventions (II): Guidelines for the study of animal and human ventricular and supraventricular arrhythmias. Pharmacol Ther 2013; 139:213-48. [DOI: 10.1016/j.pharmthera.2013.04.008] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 12/17/2022]
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Ajijola OA, Vaseghi M, Zhou W, Yamakawa K, Benharash P, Hadaya J, Lux RL, Mahajan A, Shivkumar K. Functional differences between junctional and extrajunctional adrenergic receptor activation in mammalian ventricle. Am J Physiol Heart Circ Physiol 2012; 304:H579-88. [PMID: 23241324 DOI: 10.1152/ajpheart.00754.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Increased cardiac sympathetic activation worsens dispersion of repolarization and is proarrhythmic. The functional differences between intrinsic nerve stimulation and adrenergic receptor activation remain incompletely understood. This study was undertaken to determine the functional differences between efferent cardiac sympathetic nerve stimulation and direct adrenergic receptor activation in porcine ventricles. Female Yorkshire pigs (n = 13) underwent surgical exposure of the heart and stellate ganglia. A 56-electrode sock was placed over the ventricles to record epicardial electrograms. Animals underwent bilateral sympathetic stimulation (BSS) (n = 8) or norepinephrine (NE) administration (n = 5). Activation recovery intervals (ARIs) were measured at each electrode before and during BSS or NE. The degree of ARI shortening during BSS or NE administration was used as a measure of functional nerve or adrenergic receptor density. During BSS, ARI shortening was nonuniform across the epicardium (F value 9.62, P = 0.003), with ARI shortening greatest in the mid-basal lateral right ventricle and least in the midposterior left ventricle (LV) (mean normalized values: 0.9 ± 0.08 vs. 0.56 ± 0.08; P = 0.03). NE administration resulted in greater ARI shortening in the LV apex than basal segments [0.91 ± 0.04 vs. 0.63 ± 0.05 (averaged basal segments); P = 0.003]. Dispersion of ARIs increased in 50% and 60% of the subjects undergoing BSS and NE, respectively, but decreased in the others. There is nonuniform response to cardiac sympathetic activation of both porcine ventricles, which is not fully explained by adrenergic receptor density. Different pools of adrenergic receptors may mediate the cardiac electrophysiological effects of efferent sympathetic nerve activity and circulating catecholamines.
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Affiliation(s)
- Olujimi A Ajijola
- University of California-Los Angeles Cardiac Arrhythmia Center, Los Angeles, CA 90095, USA
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CALDWELL JANEC, WOOLFSON PETER, CLARKE BERNARD, GARRATT CLIFFORDJ. Ventricular Fibrillation Following Successful DC Cardioversion for Atrial Fibrillation. Pacing Clin Electrophysiol 2012; 35:e361-4. [DOI: 10.1111/j.1540-8159.2010.03020.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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To the Editor—Sympathetic innervation of the anterior left ventricular wall by the right and left stellate ganglia. Heart Rhythm 2012; 9:e21; author reply e21-2. [DOI: 10.1016/j.hrthm.2012.08.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Indexed: 11/22/2022]
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Nicolson WB, McCann GP, Brown PD, Sandilands AJ, Stafford PJ, Schlindwein FS, Samani NJ, Ng GA. A novel surface electrocardiogram-based marker of ventricular arrhythmia risk in patients with ischemic cardiomyopathy. J Am Heart Assoc 2012; 1:e001552. [PMID: 23130163 PMCID: PMC3487358 DOI: 10.1161/jaha.112.001552] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 05/02/2012] [Indexed: 11/24/2022]
Abstract
Background Better sudden cardiac death risk markers are needed in ischemic cardiomyopathy (ICM). Increased heterogeneity of electrical restitution is an important mechanism underlying the risk of ventricular arrhythmia (VA). Our aim was to develop and test a novel quantitative surface electrocardiogram–based measure of VA risk in patients with ICM: the Regional Restitution Instability Index (R2I2). Methods and Results R2I2, the mean of the standard deviation of residuals from the mean gradient for each ECG lead at a range of diastolic intervals, was measured retrospectively from high-resolution 12-lead ECGs recorded during an electrophysiology study. Patient groups were as follows: Study group, 26 patients with ICM being assessed for implantable defibrillator; Control group, 29 patients with supraventricular tachycardia undergoing electrophysiology study; and Replication group, 40 further patients with ICM. R2I2 was significantly higher in the Study patients than in Controls (mean ± standard error of the mean: 1.09±0.06 versus 0.63±0.04, P<0.001). Over a median follow-up period of 23 months, 6 of 26 Study group patients had VA or death. R2I2 predicted VA or death independently of demographic factors, electrophysiology study result, left ventricular ejection fraction, or QRS duration (Cox model, P=0.029). R2I2 correlated with peri-infarct zone as assessed by cardiac magnetic resonance imaging (r=0.51, P=0.024). The findings were replicated in the Replication group: R2I2 was significantly higher in 11 of 40 Replication patients experiencing VA (1.18±0.10 versus 0.92±0.05, P=0.019). In combined analysis of ICM cohorts, R2I2 ≥1.03 identified subjects with significantly higher risk of VA or death (43%) compared with R2I2 <1.03 (11%) (P=0.004). Conclusions In this pilot study, we have developed a novel VA risk marker, R2I2, and have shown that it correlated with a structural measure of arrhythmic risk and predicted risk of VA or death in patients with ICM. R2I2 may improve risk stratification and merits further evaluation. (J Am Heart Assoc. 2012;1:e001552 doi: 10.1161/JAHA.112.001552.)
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Affiliation(s)
- William B Nicolson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK (W.B.N., P.D.B., N.J.S., G.A.N.) ; National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester, UK (W.B.N., G.P.M., N.J.S., G.A.N.)
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