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Yu Q, Fu Q, Xia Y, Wu Y. Predictors, clinical impact, and management strategies for conduction abnormalities after transcatheter aortic valve replacement: an updated review. Front Cardiovasc Med 2024; 11:1370244. [PMID: 38650916 PMCID: PMC11033487 DOI: 10.3389/fcvm.2024.1370244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/27/2024] [Indexed: 04/25/2024] Open
Abstract
Transcatheter aortic valve replacement (TAVR) has increasingly become a safe, feasible, and widely accepted alternative surgical treatment for patients with severe symptomatic aortic stenosis. However, the incidence of conduction abnormalities associated with TAVR, including left bundle branch block (LBBB) and high-degree atrioventricular block (HAVB), remains high and is often correlated with risk factors such as the severity of valvular calcification, preexisting conditions in patients, and procedural factors. The existing research results on the impact of post-TAVR conduction abnormalities and permanent pacemaker (PPM) requirements on prognosis, including all-cause mortality and rehospitalization, remain contradictory, with varied management strategies for post-TAVR conduction system diseases across different institutions. This review integrates the latest research in the field, offering a comprehensive discussion of the mechanisms, risk factors, consequences, and management of post-TAVR conduction abnormalities. This study provides insights into optimizing patient prognosis and explores the potential of novel strategies, such as conduction system pacing, to minimize the risk of adverse clinical outcomes.
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Affiliation(s)
| | | | | | - Yanqing Wu
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, China
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2
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Chand S, Patel J, Tripathi A, Thapa S, Frishman WH, Aronow WS. Exploring the Intricate Interplay Between Obesity and Atrial Fibrillation: Mechanisms, Management, and Clinical Implications. Cardiol Rev 2024:00045415-990000000-00195. [PMID: 38230951 DOI: 10.1097/crd.0000000000000651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Atrial fibrillation (AF) stands as a prevalent and escalating cardiac arrhythmia in the United States, with obesity emerging as a prominent modifiable risk factor. This article explores the intricate relationship between obesity and AF, delving into the multifaceted pathophysiological mechanisms linking the 2 conditions. Various factors, such as autonomic dysfunction, left atrial stretch, inflammation, and hormonal imbalances, contribute to the initiation and perpetuation of AF in obese individuals. The Atrial Fibrillation Better Care pathway, emphasizing lifestyle modifications and weight loss strategies, emerges as a practical guideline for managing AF in obesity. This comprehensive review underscores the critical role of obesity as a significant modifiable risk factor for AF, urging a proactive approach to its management. Implementing the Atrial Fibrillation Better Care approach, focusing on encouraging physical activity, promoting healthy dietary habits, and raising awareness about the risks associated with obesity prove essential in preventing and mitigating the burden of AF in the obese population.
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Affiliation(s)
- Swati Chand
- From the Departments of Cardiology
- Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY
| | - Jay Patel
- Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY
| | - Ashish Tripathi
- Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY
| | - Sangharsha Thapa
- Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY
| | - William H Frishman
- Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY
| | - Wilbert S Aronow
- From the Departments of Cardiology
- Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY
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Dong H, Chen H, Hidru TH, Xia Y, Yang X. Sinus node dysfunction and stroke risk: a systematic review and meta-analysis. BMJ Open 2023; 13:e076499. [PMID: 37977871 PMCID: PMC10660976 DOI: 10.1136/bmjopen-2023-076499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
OBJECTIVES The role of cardiac arrhythmia in ischaemic stroke is widely studied, but the size of the stroke risk in patients with sinus node dysfunction (SND) with and without atrial fibrillation (AF) is unclear. This systematic review and meta-analysis aimed to compare the risk of stroke and its associated factors in patients with SND with and without AF. DESIGN A systematic review and meta-analysis was conducted based on the Grading of Recommendations, Assessment, Development and Evaluation approach. DATA SOURCES PubMed, EMBASE and Cochrane Database were searched until December 2022. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Studies that investigate stroke in patients with SND diagnosed with or without AF/atrial flutter. DATA EXTRACTION AND SYNTHESIS Two independent authors screened studies for inclusion and extracted data. Literature quality assessment was performed using the Newcastle-Ottawa Scale and the Cochrane Collaboration Tool. The overall risk of stroke was estimated using the random-effects model. The generic inverse variance method was used to calculate the pooled estimates of stroke-associated factors. We performed a sensitivity analysis using a fixed-effects model. RESULTS Of the 929 records retrieved, 6 papers (106 163 patients) met the inclusion criteria. The average yearly stroke incidence in patients with SND was 1.542% (95% CI: 1.334% to 1.749%). The stroke incidence was similar between the isolated SND (1.587%; 95% CI: 1.510% to 1.664%) and non-isolated (SND+AF) (1.660%; 95% CI: 0.705% to 2.615%) groups. AF (HR, 95% CI: 1.53 (1.01 to 2.33)), stroke/transient ischaemia attack/other thrombotic events (HR, 95% CI: 2.54 (1.14 to 5.69)), hypertension (HR, 95% CI: 1.51 (1.11 to 2.07)) and heart failure (HR, 95% CI: 1.41 (1.01 to 1.97)) were associated with stroke in the SND population. CONCLUSION Our findings suggest that patients with SND carry a similar risk of stroke to those with combined SND and AF. Future studies are needed to investigate whether interventions targeting stroke prevention, such as anticoagulation therapy, can help to prevent stroke in patients with SND. PROSPERO REGISTRATION NUMBER CRD42023408436.
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Affiliation(s)
- Haoyu Dong
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Hao Chen
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | | | - Yunlong Xia
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Xiaolei Yang
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
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Gerach T, Schuler S, Wachter A, Loewe A. The Impact of Standard Ablation Strategies for Atrial Fibrillation on Cardiovascular Performance in a Four-Chamber Heart Model. Cardiovasc Eng Technol 2023; 14:296-314. [PMID: 36652165 PMCID: PMC10102113 DOI: 10.1007/s13239-022-00651-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/29/2022] [Indexed: 01/19/2023]
Abstract
PURPOSE Atrial fibrillation is one of the most frequent cardiac arrhythmias in the industrialized world and ablation therapy is the method of choice for many patients. However, ablation scars alter the electrophysiological activation and the mechanical behavior of the affected atria. Different ablation strategies with the aim to terminate atrial fibrillation and prevent its recurrence exist but their impact on the performance of the heart is often neglected. METHODS In this work, we present a simulation study analyzing five commonly used ablation scar patterns and their combinations in the left atrium regarding their impact on the pumping function of the heart using an electromechanical whole-heart model. We analyzed how the altered atrial activation and increased stiffness due to the ablation scars affect atrial as well as ventricular contraction and relaxation. RESULTS We found that systolic and diastolic function of the left atrium is impaired by ablation scars and that the reduction of atrial stroke volume of up to 11.43% depends linearly on the amount of inactivated tissue. Consequently, the end-diastolic volume of the left ventricle, and thus stroke volume, was reduced by up to 1.4 and 1.8%, respectively. During ventricular systole, left atrial pressure was increased by up to 20% due to changes in the atrial activation sequence and the stiffening of scar tissue. CONCLUSION This study provides biomechanical evidence that atrial ablation has acute effects not only on atrial contraction but also on ventricular performance. Therefore, the position and extent of ablation scars is not only important for the termination of arrhythmias but is also determining long-term pumping efficiency. If confirmed in larger cohorts, these results have the potential to help tailoring ablation strategies towards minimal global cardiovascular impairment.
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Affiliation(s)
- Tobias Gerach
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
| | - Steffen Schuler
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Andreas Wachter
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Axel Loewe
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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5
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Dhillon GS, Honarbakhsh S, Graham A, Ahluwalia N, Abbas H, Welch S, Daw H, Chow A, Earley MJ, Providencia R, Schilling RJ, Lambiase PD, Hunter RJ. Driver characteristics associated with structurally and electrically remodeled atria in persistent atrial fibrillation. Heart Rhythm O2 2022; 3:631-638. [PMID: 36589910 PMCID: PMC9795306 DOI: 10.1016/j.hroo.2022.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Background Recent studies suggest persistent atrial fibrillation (AF) is maintained by localized focal or rotational electrical activations termed drivers. Objective The purpose of this study was to evaluate how left atrial (LA) dilation and time in AF impact persistent AF mechanisms. Methods Patients with persistent AF <2 years underwent electrocardiographic image mapping. Potential drivers (PDs) were defined as rotational wavefront activity ≥1.5 revolutions or focal activations. Distribution of PDs was recorded using an 18-segment model. Results One hundred patients were enrolled (age 61.3 ± 12.1 years). Of these patients, 47 were hypertensive, 14 had diabetes mellitus, and 10 had ischemic heart disease. AF duration was 8 [5-15] months. Median LA diameter was 39 [33-43] mm. Although LA dimensions did not correlate with overall PD burden or distribution, there was a modest correlation between increasing LA area (r = 0.235; P = .024) and LA volume (r = 0.216; P = .039) with proportion of PDs that were rotational. Although time in AF did not correlate with overall PD burden or distribution, there was a correlation between time in AF and the number of focal PDs (r = 0.203; P = .044). Female gender, increasing age, and hypertension also were associated with an increase in focal PDs. Conclusion This is the first study to demonstrate different AF mechanisms in patient subgroups. Greater understanding of patient-specific AF mechanisms may facilitate a tailored approach to AF mapping and ablation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Ross J. Hunter
- Address reprint requests and correspondence: Dr Ross Hunter, Barts Heart Centre, Barts Heart NHS Trust, West Smithfield, London EC1A 7BE, United Kingdom.
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6
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What keeps us ticking? Sinoatrial node mechano-sensitivity: the grandfather clock of cardiac rhythm. Biophys Rev 2021; 13:707-716. [PMID: 34777615 DOI: 10.1007/s12551-021-00831-8] [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] [Received: 07/25/2021] [Accepted: 08/17/2021] [Indexed: 01/01/2023] Open
Abstract
The rhythmic and spontaneously generated electrical excitation that triggers the heartbeat originates in the sinoatrial node (SAN). SAN automaticity has been thoroughly investigated, which has uncovered fundamental mechanisms involved in cardiac pacemaking that are generally categorised into two interacting and overlapping systems: the 'membrane' and 'Ca2+ clock'. The principal focus of research has been on these two systems of oscillators, which have been studied primarily in single cells and isolated tissue, experimental preparations that do not consider mechanical factors present in the whole heart. SAN mechano-sensitivity has long been known to be a contributor to SAN pacemaking-both as a driver and regulator of automaticity-but its essential nature has been underappreciated. In this review, following a description of the traditional 'clocks' of SAN automaticity, we describe mechanisms of SAN mechano-sensitivity and its vital role for SAN function, making the argument that the 'mechanics oscillator' is, in fact, the 'grandfather clock' of cardiac rhythm.
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O’Neill L, Wielandts JY, Gillis K, Hilfiker G, Le Polain De Waroux JB, Tavernier R, Duytschaever M, Knecht S. Catheter Ablation in Persistent AF, the Evolution towards a More Pragmatic Strategy. J Clin Med 2021; 10:jcm10184060. [PMID: 34575173 PMCID: PMC8467025 DOI: 10.3390/jcm10184060] [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] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/27/2021] [Accepted: 09/04/2021] [Indexed: 11/16/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and represents a heterogeneous disorder with a complex pathological basis. While significant technological advances have taken place over the last decade in the field of catheter ablation of AF, response to ablation varies and long-term success rates in those with persistent AF remain modest. Mechanistic studies have highlighted potentially different sustaining factors for AF in the persistent AF population with substrate-driven focal and re-entrant sources in the body of the atria identified on invasive and non-invasive mapping studies. Translation to clinical practice, however, remains challenging and the application of such mapping techniques to clinical ablation has yet to demonstrate a significant benefit beyond pulmonary vein isolation (PVI) alone in the persistent AF cohort. Recent advances in catheter and ablation technology have centered on improving the durability of ablation lesions at index procedure and although encouraging results have been demonstrated with early studies, large-scale trials are awaited. Further meaningful improvement in clinical outcomes in the persistent AF population requires ongoing advancement in the understanding of AF mechanisms, coupled with continuing progress in catheter technology capable of delivering durable transmural lesions.
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Scovner KM, Correa S, Claggett BL, Barrett CD, Waikar SS, Solomon SD, Mc Causland FR. Specific Electrocardiograph Intervals Predict Hospitalization with Atrial Fibrillation in Those with Chronic Kidney Disease. Am J Nephrol 2021; 52:412-419. [PMID: 33951623 DOI: 10.1159/000515670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/02/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Atrial fibrillation (AF) is common in patients with chronic kidney disease (CKD) and is associated with higher rates of hospitalization compared to those without AF. Whether routine electrocardiographic parameters are predictive of future hospitalizations with AF is not clear. METHODS The present study is an analysis of a prospective cohort of 2,759 patients without baseline AF from the Chronic Renal Insufficiency Cohort, a large prospective multicenter study of patients with nondialysis-dependent CKD. Unadjusted and adjusted Cox regression models were fit to examine the association of baseline categories of QTc, QRS, and PR intervals with time to first hospitalization with AF. Restricted cubic splines were used to display nonlinear associ-ations. RESULTS The mean age of subjects at baseline was 58 ± 11 years, 55% were male, and 44% were Black. The mean follow-up was 6.6 years during which 224 participants experienced a hospitalization with AF. The association of baseline QTc interval with risk of AF hospitalization was nonlinear, such that the lowest and highest quartiles of QTc (<407 and >431 ms, respectively) had higher adjusted risk of AF hospitalization, compared with the second quartile (407-416 ms) (aHR Q1:Q2 1.58, 95% CI 1.03-2.41; p = 0.03; aHR Q4:Q2 1.84, 95% CI 1.22-2.78; p < 0.01). Longer QRS was associated with a higher risk of hospitalization with AF among the subgroup of patients with a history of heart failure (HF). PR interval was not associated with AF hospitalization. DISCUSSION/CONCLUSION The association of QTc with risk for hospitalization with AF among patients with CKD is nonlinear, while the association of longer QRS with AF hospitalization is restricted to patients with baseline HF. Electrocardiography may represent a simple and widely accessible method for risk stratification of future AF in patients with CKD.
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Affiliation(s)
- Katherine Mikovna Scovner
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Simon Correa
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Brian L Claggett
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Conor D Barrett
- Harvard Medical School, Boston, Massachusetts, USA
- Division of Cardiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Sushrut S Waikar
- Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts, USA
| | - Scott D Solomon
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Finnian R Mc Causland
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
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DDD mode-switching and loss of atrioventricular synchrony evokes heart failure: A rare but possible trigger of pacing-induced cardiomyopathy. J Cardiol Cases 2021; 23:158-162. [PMID: 33841592 DOI: 10.1016/j.jccase.2020.11.003] [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] [Received: 06/16/2020] [Revised: 10/20/2020] [Accepted: 10/27/2020] [Indexed: 11/21/2022] Open
Abstract
Pacing-induced cardiomyopathy (PICM), defined as left ventricular dysfunction, occurs in the setting of chronic, high burden right ventricular pacing. We describe an unusual case of PICM. A 64-year-old man underwent a medical check-up and was diagnosed with complete atrioventricular block (AVB) with regular and slow ventricular contractions at 38 beats/min (bpm). The patient underwent a pacemaker implantation with a dual-chamber pacing (DDD) pacemaker. This patient had no symptoms or signs of PICM during complete AVB or the period after undergoing dual-chamber pacing. However, PICM developed within a short time after the onset of atrial flutter (AFL). During AFL, the automatic mode switch of the DDD pacemaker to the DDIR mode worked normally, and the ventricles were paced with a stable and regular rate (60 bpm). Despite the administration of ß-blockers and diuretics, his symptoms and status did not improve. After the elimination of the AFL and restoration of AV synchrony with a DDD mode by catheter ablation, the deteriorated condition rapidly improved. In this patient, the coexistence of the loss of AV synchrony and high burden RV pacing during AFL might have caused this unusual PICM. Learning objective: Even when patients have no symptoms or signs of pacing-induced cardiomyopathy (PICM) during complete atrioventricular block or the period after undergoing dual-chamber pacing, automatic mode-switching to the DDI mode during atrial tachyarrhythmias could rapidly cause PICM. PICM could occur with a much more rapid time course than the historical model of PICM where cardiomyopathy may take several years to develop. Much attention should be paid during the follow-up to patients receiving DDD pacemakers to avoid any unusual PICM as in this case.
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10
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Parkash R, Wells G, Rouleau J, Talajic M, Essebag V, Skanes A, Wilton SB, Verma A, Healey JS, Tang AS. A randomized ablation-based atrial fibrillation rhythm control versus rate control trial in patients with heart failure and high burden atrial fibrillation: The RAFT-AF trial rationale and design. Am Heart J 2021; 234:90-100. [PMID: 33472052 DOI: 10.1016/j.ahj.2021.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/15/2021] [Indexed: 10/22/2022]
Abstract
Heart failure (HF) and atrial fibrillation (AF) are 2 cardiac conditions that are increasing in prevalence and incidence. The 2 conditions frequently coexist, and are associated with increased morbidity and mortality. Catheter ablation of AF has been successfully performed in patients with HF, with an improvement in HF and AF, when compared to amiodarone, but further data is required to compare this to rate control. OBJECTIVES: The primary objective is to determine whether AF treated by catheter ablation, with or without antiarrhythmic drugs reduces all-cause mortality and hospitalizations for HF as compared with rate control in patients with HF and a high burden AF. METHODS: This is a multi-center prospective randomized open blinded endpoint (PROBE) study. Patients with NYHA class II-III HF (HF with reduced ejection fraction (<35%) or HF with preserved ejection fraction), and high burden AF are included in the trial. Patients are randomized to either rate control or catheter ablation-based AF rhythm control in a 1:1 ratio. Patients in the rate control group receive optimal HF therapy and rate control measures to achieve a resting hazard ratio (HR) < 80 bpm and 6-minute walk HR < 110 bpm. Patients randomized to catheter ablation-based AF rhythm control group receive optimal HF therapy and one or more aggressive catheter ablation, which include PV antral ablation and LA substrate ablation with or without adjunctive antiarrhythmic drug. The primary outcome is a composite of all-cause mortality and hospitalization for heart failure defined as an admission to a health care facility. The sample size is 600. Enrolment has been completed.
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Affiliation(s)
- Ratika Parkash
- Queen Elizabeth II Health Sciences Center, Halifax, Nova Scotia, Canada.
| | - George Wells
- University of Ottawa Cardiovascular Research Methods Center, Ottawa, ON, Canada
| | | | | | - Vidal Essebag
- McGill University Health Centre, Montreal, QC, Canada
| | - Allan Skanes
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Steve B Wilton
- Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | | | - Jeff S Healey
- Population Health Research Institute, Hamilton, ON, Canada
| | - Anthony Sl Tang
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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Al-Kaisey AM, Parameswaran R, Kalman JM. Atrial Fibrillation Structural Substrates: Aetiology, Identification and Implications. Arrhythm Electrophysiol Rev 2020; 9:113-120. [PMID: 33240506 PMCID: PMC7675137 DOI: 10.15420/aer.2020.19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Atrial remodelling in AF underlines the electrical, structural and mechanical changes in the atria of patients with AF. Several risk factors for AF contribute to the development of the atrial substrate, with some evidence that atrial remodelling reversal is possible with targeted intervention. In this article, the authors review the electrophysiological changes that characterise the atrial substrate in patients with AF risk factors. They also discuss the pitfalls of mapping the atrial substrate and the implications for developing tailored ablation strategies to improve outcomes in patients with AF.
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Affiliation(s)
- Ahmed M Al-Kaisey
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Ramanathan Parameswaran
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
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13
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Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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14
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Williams SE, O'Neill L, Roney CH, Julia J, Metzner A, Reißmann B, Mukherjee RK, Sim I, Whitaker J, Wright M, Niederer S, Sohns C, O'Neill M. Left atrial effective conducting size predicts atrial fibrillation vulnerability in persistent but not paroxysmal atrial fibrillation. J Cardiovasc Electrophysiol 2019; 30:1416-1427. [PMID: 31111557 PMCID: PMC6746623 DOI: 10.1111/jce.13990] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/01/2019] [Accepted: 05/17/2019] [Indexed: 11/30/2022]
Abstract
Background The multiple wavelets and functional re‐entry hypotheses are mechanistic theories to explain atrial fibrillation (AF). If valid, a chamber's ability to support AF should depend upon the left atrial size, conduction velocity (CV), and refractoriness. Measurement of these parameters could provide a new therapeutic target for AF. We investigated the relationship between left atrial effective conducting size (LAECS), a function of area, CV and refractoriness, and AF vulnerability in patients undergoing AF ablation. Methods and Results Activation mapping was performed in patients with paroxysmal (n = 21) and persistent AF (n = 18) undergoing pulmonary vein isolation. Parameters used for calculating LAECS were: (a) left atrial body area (A); (b) effective refractory period (ERP); and (c) total activation time (T). Global CV was estimated as √A/T. Effective atrial conducting size was calculated as LAECS=A/(CV×ERP). Post ablation, AF inducibility testing was performed. The critical LAECS required for multiple wavelet termination was determined from computational modeling. LAECS was greater in patients with persistent vs paroxysmal AF (4.4 ± 2.0 cm vs 3.2 ± 1.4 cm; P = .049). AF was inducible in 14/39 patients. LAECS was greater in AF‐inducible patients (4.4 ± 1.8 cm vs 3.3 ± 1.7 cm; P = .035, respectively). The difference in LAECS between inducible and noninducible patients was significant in patients with persistent (P = .0046) but not paroxysmal AF (P = .6359). Computational modeling confirmed that LAECS > 4 cm was required for continuation of AF. Conclusions LAECS measured post ablation was associated with AF inducibility in patients with persistent, but not paroxysmal AF. These data support a role for this method in electrical substrate assessment in AF patients.
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Affiliation(s)
- Steven E Williams
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Louisa O'Neill
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Caroline H Roney
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Justo Julia
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Andreas Metzner
- Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany
| | - Bruno Reißmann
- Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany
| | - Rahul K Mukherjee
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Iain Sim
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - John Whitaker
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Matthew Wright
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Steven Niederer
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Christian Sohns
- Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany.,Clinic for Electrophysiology, Herz- und Diabeteszentrum NRW, Ruhr-Universität Bochum, Bad Oeynhausen, Germany
| | - Mark O'Neill
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
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15
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Suzuki Y, Takei A, Takahara H, Taniguchi Y, Ozawa T, Inoue N. A case of atrial standstill with the atrial lead of a dual-chamber pacemaker implanted in the coronary sinus. HeartRhythm Case Rep 2019; 5:338-342. [PMID: 31285994 PMCID: PMC6587059 DOI: 10.1016/j.hrcr.2019.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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16
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Vora AN, Dai D, Matsuoka R, Harrison JK, Hughes GC, Sherwood MW, Piccini JP, Bhardwaj B, Lopes RD, Cohen D, Holmes DR, Thourani VH, Peterson E, Kirtane A, Kapadia S, Vemulapalli S. Incidence, Management, and Associated Clinical Outcomes of New-Onset Atrial Fibrillation Following Transcatheter Aortic Valve Replacement. JACC Cardiovasc Interv 2018; 11:1746-1756. [DOI: 10.1016/j.jcin.2018.05.042] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 05/14/2018] [Accepted: 05/14/2018] [Indexed: 11/12/2022]
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17
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Wali E, Deshmukh A, Bukari A, Broman M, Aziz Z, Beaser A, Upadhyay G, Nayak HM, Tung R, Ozcan C. Impact of high-grade atrioventricular block and cumulative frequent pacing on atrial arrhythmias. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2018; 41:1158-1164. [PMID: 29931776 DOI: 10.1111/pace.13425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/12/2018] [Accepted: 06/11/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND The relationship between high-grade atrioventricular block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized. We hypothesized HGAVB and pacing may have significant impact on incidence and prevalence of AAs by modulating atrial substrate. OBJECTIVE To determine impact of HGAVB and pacing on AAs including atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT). METHODS All consecutive patients who underwent dual-chamber pacemaker implantation for HGAVB from 2005 to 2011 at the University of Chicago were included. AAs and percent of pacing were detected through device interrogation. Patients' data were collected from electronic medical records and clinic visits. RESULTS A total of 166 patients (mean age 71 ± 15 years; 54% female, 56% African American) were studied. AF was documented in 27% of patients before pacemaker implantation. During a mean 5.8 ± 2.2 years of follow-up, 47% had device-detected AF, 10% AFL, and 26% AT. New-onset AF was documented in 40 of the 122 patients without prior AF (33%). Continuous (≥ 99%) right ventricular pacing was associated with significantly decreased AF prevalence (34% vs 59%, P = 0.005), and correlated with lower incidence (26% vs 41%, P = 0.22). Pacing suppressed AF in 14% of patients with baseline AF; those patients had lower atrial pacing (3.2% vs 45%, P < 0.0001). Left atrial dilation was the only independent predictor of AF with frequent pacing (P = 0.009). CONCLUSIONS HGAVB is associated with high incidence and prevalence of AAs with and without pacing. Cumulative frequent (≥99%) ventricular pacing reduces risk of AF in patients with HGAVB.
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Affiliation(s)
- Eisha Wali
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Amrish Deshmukh
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Abdallah Bukari
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA.,Department of Medicine, Northshore University Health System, Chicago, IL, USA
| | - Michael Broman
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Zaid Aziz
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Andrew Beaser
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Gaurav Upadhyay
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Hemal M Nayak
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Roderick Tung
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
| | - Cevher Ozcan
- Department of Medicine, Section of Cardiology, University of Chicago, Chicago, IL, USA
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18
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Kishima H, Mine T, Takahashi S, Ashida K, Ishihara M, Masuyama T. Left atrial ejection force predicts the outcome after catheter ablation for paroxysmal atrial fibrillation. J Cardiovasc Electrophysiol 2017; 29:264-271. [PMID: 29125704 DOI: 10.1111/jce.13387] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/27/2017] [Accepted: 11/02/2017] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Left atrium (LA) systolic dysfunction is observed in the early stages of atrial fibrillation (AF) prior to LA anatomical change. We investigated whether LA systolic dysfunction predicts recurrent AF after catheter ablation (CA) in patients with paroxysmal AF. METHODS AND RESULTS We studied 106 patients who underwent CA for paroxysmal AF. LA systolic function was assessed with the LA emptying volume = Maximum LA volume (LAVmax ) - Minimum LA volume (LAVmin ), LA emptying fraction = [(LAVmax - LAVmin )/LAVmax ] × 100, and LA ejection force calculated with Manning's method [LA ejection force = (0.5 × ρ × mitral valve area × A2 )], where ρ is the blood density and A is the late-diastolic mitral inflow velocity. Recurrent AF was detected in 35/106 (33%) during 14.6 ± 9.1 months. Univariate analysis revealed reduced LA ejection force, decreased LA emptying fraction, larger LA diameter, and elevated brain natriuretic peptide as significant variables. On multivariate analysis, reduced LA ejection force and larger LA diameter were independently associated with recurrent AF. Moreover, patients with reduced LA ejection force and larger LA diameter had a higher risk of recurrent AF than preserved LA ejection force (log-rank P = 0.0004). CONCLUSIONS Reduced LA ejection force and larger LA diameter were associated with poor outcome after CA for paroxysmal AF, and could be a new index to predict recurrent AF.
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Affiliation(s)
- Hideyuki Kishima
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Takanao Mine
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Satoshi Takahashi
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Kenki Ashida
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Masaharu Ishihara
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Tohru Masuyama
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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19
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MacDonald EA, Stoyek MR, Rose RA, Quinn TA. Intrinsic regulation of sinoatrial node function and the zebrafish as a model of stretch effects on pacemaking. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:198-211. [PMID: 28743586 DOI: 10.1016/j.pbiomolbio.2017.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/18/2022]
Abstract
Excitation of the heart occurs in a specialised region known as the sinoatrial node (SAN). Tight regulation of SAN function is essential for the maintenance of normal heart rhythm and the response to (patho-)physiological changes. The SAN is regulated by extrinsic (central nervous system) and intrinsic (neurons, peptides, mechanics) factors. The positive chronotropic response to stretch in particular is essential for beat-by-beat adaptation to changes in hemodynamic load. Yet, the mechanism of this stretch response is unknown, due in part to the lack of an appropriate experimental model for targeted investigations. We have been investigating the zebrafish as a model for the study of intrinsic regulation of SAN function. In this paper, we first briefly review current knowledge of the principal components of extrinsic and intrinsic SAN regulation, derived primarily from experiments in mammals, followed by a description of the zebrafish as a novel experimental model for studies of intrinsic SAN regulation. This mini-review is followed by an original investigation of the response of the zebrafish isolated SAN to controlled stretch. Stretch causes an immediate and continuous increase in beating rate in the zebrafish isolated SAN. This increase reaches a maximum part way through a period of sustained stretch, with the total change dependent on the magnitude and direction of stretch. This is comparable to what occurs in isolated SAN from most mammals (including human), suggesting that the zebrafish is a novel experimental model for the study of mechanisms involved in the intrinsic regulation of SAN function by mechanical effects.
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Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Matthew R Stoyek
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Robert A Rose
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada; School of Biomedical Engineering, Dalhousie University, Halifax, Canada.
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20
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Thanigaimani S, McLennan E, Linz D, Mahajan R, Agbaedeng TA, Lee G, Kalman JM, Sanders P, Lau DH. Progression and reversibility of stretch induced atrial remodeling: Characterization and clinical implications. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:376-386. [PMID: 28734850 DOI: 10.1016/j.pbiomolbio.2017.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 12/13/2022]
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia and across the developed nations, it contributes to increasing hospitalizations and healthcare burden. Several comorbidities and risk factors including hypertension, heart failure, obstructive sleep apnoea and obesity are known to play an important role in the initiation and perpetuation of AF and atrial stretch or dilatation may play a central mechanistic role. The impact of atrial stretch in the development of AF can vary dependent on the underlying disease. This review focuses on understanding the substrate for AF in conditions of acute and chronic stretch and in the presence of common co-morbidities or risk factors through the review of findings in both animal and human studies. Additionally, the reversibility of atrial remodeling following stretch release will also be discussed. Identification of clinical conditions associated with increased atrial stretch as well as the treatment or prevention of these conditions may help to prevent AF progression and improve sinus rhythm maintenance.
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Affiliation(s)
- Shivshankar Thanigaimani
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Emma McLennan
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Dominik Linz
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Rajiv Mahajan
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Thomas A Agbaedeng
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Geoffrey Lee
- Department of Cardiology, Royal Melbourne Hospital and Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital and Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Dennis H Lau
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia.
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21
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Multiphysics Modeling of the Atrial Systole under Standard Ablation Strategies. Cardiovasc Eng Technol 2017; 8:205-218. [DOI: 10.1007/s13239-017-0308-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 05/10/2017] [Indexed: 11/26/2022]
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22
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Nalliah CJ, Sanders P, Kalman JM. Obstructive Sleep Apnea Treatment and Atrial Fibrillation: A Need for Definitive Evidence. J Cardiovasc Electrophysiol 2016; 27:1001-10. [PMID: 27060686 DOI: 10.1111/jce.12981] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 03/20/2016] [Accepted: 03/29/2016] [Indexed: 11/29/2022]
Abstract
Prevalence rates of atrial fibrillation (AF) and obstructive sleep apnea (OSA) are rising on a global scale. Epidemiological data have consistently demonstrated an independent association between the 2 conditions. Investigators pose that pathophysiologic features of OSA enable progression of the AF substrate; these features include abnormalities of gas exchange, autonomic remodeling, atrial stretch, and inflammation. Furthermore, many of the mechanistic perturbations that impact the AF substrate in OSA can be substantially attenuated by effective treatment with continuous positive airway pressure (CPAP). Clear associations of OSA treatment and improved AF control have been observed across multiple clinical contexts. However, the precision and generalizability of these findings are unclear in view of the data's observational nature. Although risk factor management has emerged as a critical component of AF treatment, effective control of many AF risk factors can be challenging in the longer term. In view of the efficacy and sustainability of CPAP therapy, OSA raises its profile as a prime candidate for intervention. However, translation of this strategy to the broader framework for AF management requires robust data from randomized controlled trials.
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Affiliation(s)
- Chrishan J Nalliah
- Department of Cardiology, Royal Melbourne Hospital and the Department of Medicine, University of Melbourne, Melbourne, Australia.,Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital and the Department of Medicine, University of Melbourne, Melbourne, Australia
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KISHIMA HIDEYUKI, MINE TAKANAO, TAKAHASHI SATOSHI, ASHIDA KENKI, ISHIHARA MASAHARU, MASUYAMA TOHRU. The Impact of Elevated Left Atrial Pressure in Sinus Rhythm After Cardioversion on Outcomes After Catheter Ablation for Atrial Fibrillation. J Cardiovasc Electrophysiol 2016; 27:813-9. [DOI: 10.1111/jce.12993] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- HIDEYUKI KISHIMA
- Cardiovascular Division, Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Japan
| | - TAKANAO MINE
- Cardiovascular Division, Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Japan
| | - SATOSHI TAKAHASHI
- Cardiovascular Division, Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Japan
| | - KENKI ASHIDA
- Cardiovascular Division, Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Japan
| | - MASAHARU ISHIHARA
- Cardiovascular Division, Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Japan
| | - TOHRU MASUYAMA
- Cardiovascular Division, Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Japan
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24
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Abadir S, Fournier A, Vobecky SJ, Rohlicek CV, Romeo P, Khairy P. Left Atrial Inexcitability in Children With Congenital Lupus-Induced Complete Atrioventricular Block. J Am Heart Assoc 2015; 4:JAHA.115.002676. [PMID: 26675254 PMCID: PMC4845288 DOI: 10.1161/jaha.115.002676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Background Congenital atrioventricular block is a well‐established immunologic complication of maternal systemic lupus erythematosus. We sought to further characterize the electrophysiological manifestations of maternal systemic lupus erythematosus on neonatal atria. Methods and Results Cases of isolated congenital atrioventricular block treated at our center over the past 41 years were identified. Data were extracted from clinical charts, pacemaker interrogations, ECGs, echocardiograms, and histopathological reports, when available. Of 31 patients with isolated congenital atrioventricular block, 18 were negative for maternal antibodies and had normal epicardial atrial sensing and pacing thresholds. In contrast, 12 of 13 patients with positive maternal antibodies had epicardial pacemakers, 5 (42%) of whom had left atrial (LA) inexcitability and/or atrial conduction delay. In 3 patients, the LA could not be captured despite high‐output pacing. The fourth patient had acutely successful LA appendage and left ventricular lead placement. At early follow‐up, an increased delay between the surface P‐wave and intracardiac atrial depolarization was observed, indicative of atrial conduction delay. The fifth patient exhibited LA lead dysfunction, with atrial under‐sensing and an increased capture threshold, 2 weeks after implantation. Biopsies of LA appendages performed in 2 patients showed no evidence of atrial fibrosis or loss of atrial myocytes. Conclusions Herein, we report previously undescribed yet prevalent electrophysiological ramifications of maternal systemic lupus erythematosus, which extend beyond congenital atrioventricular block to encompass alterations in LA conduction, including LA inexcitability. These manifestations can complicate epicardial pacemaker implantation in newborns. In the absence of histological evidence of extensive atrial fibrosis, immune‐mediated functional impairment of electrical activity is suspected.
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Affiliation(s)
- Sylvia Abadir
- Divisions of Cardiology and Cardiac Surgery, CHU mère-enfant Sainte-Justine, Université de Montréal, Quebec, Canada (S.A., A.F., S.J.V., P.K.) Department of Cardiology, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada (S.A., C.V.R.)
| | - Anne Fournier
- Divisions of Cardiology and Cardiac Surgery, CHU mère-enfant Sainte-Justine, Université de Montréal, Quebec, Canada (S.A., A.F., S.J.V., P.K.)
| | - Suzanne J Vobecky
- Divisions of Cardiology and Cardiac Surgery, CHU mère-enfant Sainte-Justine, Université de Montréal, Quebec, Canada (S.A., A.F., S.J.V., P.K.)
| | - Charles V Rohlicek
- Department of Cardiology, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada (S.A., C.V.R.)
| | - Philippe Romeo
- Department of Medicine and Pathology, Montreal Heart Institute, Université de Montréal, Québec, Canada (P.R., P.K.)
| | - Paul Khairy
- Divisions of Cardiology and Cardiac Surgery, CHU mère-enfant Sainte-Justine, Université de Montréal, Quebec, Canada (S.A., A.F., S.J.V., P.K.) Department of Medicine and Pathology, Montreal Heart Institute, Université de Montréal, Québec, Canada (P.R., P.K.)
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25
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Nalliah CJ, Sanders P, Kottkamp H, Kalman JM. The role of obesity in atrial fibrillation. Eur Heart J 2015; 37:1565-72. [DOI: 10.1093/eurheartj/ehv486] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/25/2015] [Indexed: 11/13/2022] Open
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26
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Posterior left atrial isolation for atrial fibrillation in left ventricular diastolic impairment is associated with better arrhythmia free survival. Int J Cardiol 2015; 184:674-679. [DOI: 10.1016/j.ijcard.2015.01.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/22/2014] [Accepted: 01/26/2015] [Indexed: 11/19/2022]
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27
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Lange JM, Manzolillo H, Parras J, Pozzer D, Reyes I, Pantich R. [Right ventricular septal stimulation would produce similar bi-ventricular dyssynchrony as does apical stimulation in patients with normal ejection fraction]. ARCHIVOS DE CARDIOLOGIA DE MEXICO 2014; 84:183-90. [PMID: 25091614 DOI: 10.1016/j.acmx.2013.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 11/23/2013] [Accepted: 11/28/2013] [Indexed: 10/24/2022] Open
Abstract
OBJECTIVE To determine in patients with normal ejection fraction, undergoing permanent VVI pacing, if medial septal stimulation has lower dyssynchrony than apical stimulation assessed by echocardiography. METHOD A prospective trial, 19 patients>70 years old, scheduled for VVI pacemaker implantation for complete degenerative atrioventricular block, ventricular frequency<50beat per minute and ejection fraction≥45%. Patients with atrial fibrillation, heart failure, left bundle branch block and QRS durations longer than 120milliseconds in surface electrocardiogram with sinus rhythm were excluded. Patients were randomized to apical implantation group A: 47% and septal implantation group B: 53%. Echocardiographic parameters were measured previous to the implant, 48h, 5 and 48 months after implantation. RESULTS No patients had diagnosis of ischemic cardiomyopathy or heart failure. Echocardiographic parameters for interventricular dyssynchrony between groups were A: 14.44±19.76msec vs. B: 9±36.45msec; A: 6.11±62.11msec vs. B: 13±38.31msec; A: 77±53.51msec vs. B: 24.29±80.90msec, P=NS). For interventricular dyssynchrony were A: 46.44±19.76msec vs. B: 42.20±29.56msec; A: 45.33±45.67msec vs. B: 29.80±44.66msec; A: 46,38±20 msec vs. B: 21±27.20msec, P=NS) at 48h, 5 and 48 months, respectively. CONCLUSION Apical site of stimulation does not increase ventricular dyssynchrony rate in patients with preserved ejection fraction. Septal stimulation showed decreased trend in interventricular dyssynchrony.
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Affiliation(s)
- Juan Manuel Lange
- Residencia de Cardiología Clínica, Instituto de Cardiología de Corrientes Juana Francisca Cabral, Corrientes, Corrientes, Argentina.
| | - Hector Manzolillo
- Departamento de Cardiología y Electro Fisiología, Instituto de Cardiología de Corrientes Juana Francisca Cabral, Corrientes, Corrientes, Argentina
| | - Jorge Parras
- Departamentos de Cardiología y Ecocardiografía, Instituto de Cardiología de Corrientes Juana Francisca Cabral, Corrientes, Corrientes, Argentina
| | - Domingo Pozzer
- Departamento de Cardiología y Electro Fisiología, Instituto de Cardiología de Corrientes Juana Francisca Cabral, Corrientes, Corrientes, Argentina
| | - Ignacio Reyes
- Departamento de Cardiología y Electro Fisiología, Instituto de Cardiología de Corrientes Juana Francisca Cabral, Corrientes, Corrientes, Argentina
| | - Rolando Pantich
- Departamento de Cardiología y Electro Fisiología, Instituto de Cardiología de Corrientes Juana Francisca Cabral, Corrientes, Corrientes, Argentina
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Limantoro I, de Vos CB, Delhaas T, Weijs B, Blaauw Y, Schotten U, Kietselaer B, Pisters R, Crijns HJGM. Clinical correlates of echocardiographic tissue velocity imaging abnormalities of the left atrial wall during atrial fibrillation. Europace 2014; 16:1546-53. [DOI: 10.1093/europace/euu047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Affiliation(s)
- Gwilym M Morris
- Institute of Cardiovascular Sciences, University of Manchester, Core Technology Facility
- Department of Cardiology, The Royal Melbourne Hospital
| | - Jonathan M Kalman
- Department of Cardiology, The Royal Melbourne Hospital
- Department of Medicine, Melbourne University
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30
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Pathak R, Lau DH, Mahajan R, Sanders P. Structural and Functional Remodeling of the Left Atrium: Clinical and Therapeutic Implications for Atrial Fibrillation. J Atr Fibrillation 2013; 6:986. [PMID: 28496919 DOI: 10.4022/jafib.986] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 12/12/2022]
Abstract
Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice. Despite advances in our understanding of the pathophysiology of this complex arrhythmia, current therapeutic options remain suboptimal. This review aimed to delineate the atrial structural and functional remodeling leading to the perpetuation of AF. We explored the complex changes seen in the atria in various substrates for AF and the therapeutic options available to prevent these changes or for reverse remodeling. Here we also highlighted the emerging role of aggressive risk factor management aimed at the arrhythmogenic atrial substrate to prevent or retard AF progression.
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Affiliation(s)
- Rajeev Pathak
- Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - Dennis H Lau
- Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - Rajiv Mahajan
- Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
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31
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LAU CHUPAK, TSE HUNGFAT, SIU CHUNGWAH, GBADEBO DAVID. Atrial Electrical and Structural Remodeling: Implications for Racial Differences in Atrial Fibrillation. J Cardiovasc Electrophysiol 2012; 23 Suppl 1:S36-40. [DOI: 10.1111/jce.12022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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32
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Atrial remodeling in varying clinical substrates within beating human hearts: Relevance to atrial fibrillation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:278-94. [DOI: 10.1016/j.pbiomolbio.2012.07.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 07/24/2012] [Indexed: 11/19/2022]
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Quinn TA, Kohl P. Mechano-sensitivity of cardiac pacemaker function: pathophysiological relevance, experimental implications, and conceptual integration with other mechanisms of rhythmicity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:257-68. [PMID: 23046620 PMCID: PMC3526794 DOI: 10.1016/j.pbiomolbio.2012.08.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 08/09/2012] [Indexed: 12/11/2022]
Abstract
Cardiac pacemaker cells exhibit spontaneous, rhythmic electrical excitation, termed automaticity. This automatic initiation of action potentials requires spontaneous diastolic depolarisation, whose rate determines normal rhythm generation in the heart. Pacemaker mechanisms have been split recently into: (i) cyclic changes in trans-sarcolemmal ion flows (termed the ‘membrane-clock’), and (ii) rhythmic intracellular calcium cycling (the ‘calcium-clock’). These two ‘clocks’ undoubtedly interact, as trans-sarcolemmal currents involved in pacemaking include calcium-carrying mechanisms, while intracellular calcium cycling requires trans-sarcolemmal ion flux as the mechanism by which it affects membrane potential. The split into separate ‘clocks’ is, therefore, somewhat arbitrary. Nonetheless, the ‘clock’ metaphor has been conceptually stimulating, in particular since there is evidence to support the view that either ‘clock’ could be sufficient in principle to set the rate of pacemaker activation. Of course, the same has also been shown for sub-sets of ‘membrane-clock’ ion currents, illustrating the redundancy of mechanisms involved in maintaining such basic functionality as the heartbeat, a theme that is common for vital physiological systems. Following the conceptual path of identifying individual groups of sub-mechanisms, it is important to remember that the heart is able to adapt pacemaker rate to changes in haemodynamic load, even after isolation or transplantation, and on a beat-by-beat basis. Neither the ‘membrane-’ nor the ‘calcium-clock’ do, as such, inherently account for this rapid adaptation to circulatory demand (cellular Ca2+ balance changes over multiple beats, while variation of sarcolemmal ion channel presence takes even longer). This suggests that a third set of mechanisms must be involved in setting the pace. These mechanisms are characterised by their sensitivity to the cyclically changing mechanical environment, and – in analogy to the above terminology – this might be considered a ‘mechanics-clock’. In this review, we discuss possible roles of mechano-sensitive mechanisms for the entrainment of membrane current dynamics and calcium-handling. This can occur directly via stretch-activation of mechano-sensitive ion channels in the sarcolemma and/or in intracellular membrane compartments, as well as by modulation of ‘standard’ components of the ‘membrane-’ or ‘calcium-clock’. Together, these mechanisms allow rapid adaptation to changes in haemodynamic load, on a beat-by-beat basis. Additional relevance arises from the fact that mechano-sensitivity of pacemaking may help to explain pacemaker dysfunction in mechanically over- or under-loaded tissue. As the combined contributions of the various underlying oscillatory mechanisms are integrated at the pacemaker cell level into a single output – a train of pacemaker action potentials – we will not adhere to a metaphor that implies separate time-keeping units (‘clocks’), and rather focus on cardiac pacemaking as the result of interactions of a set of coupled oscillators, whose individual contributions vary depending on the pathophysiological context. We conclude by considering the utility and limitations of viewing the pacemaker as a coupled system of voltage-, calcium-, and mechanics-modulated oscillators that, by integrating a multitude of inputs, offers the high level of functional redundancy that is vitally important for cardiac automaticity.
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Affiliation(s)
- T Alexander Quinn
- National Heart and Lung Institute, Imperial College London, London, UK.
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Abstract
PURPOSE OF REVIEW Sinus node disease (SND) is a common clinical condition and is the most common indication for permanent pacemaker implantation. This review aims to revisit the complex sinus node anatomy, the evolving understanding of its pacemaking mechanisms, the atrial myopathy in SND and sinus node remodeling. RECENT FINDINGS Recent high-density noncontact mapping of the human sinus node showed multiple origins of sinus activation and exit sites with preferential pathways of conduction. Perhaps, a newly described discrete paranodal area containing a molecular mixture of nodal and atrial cells may account for this long recognized discrepancy between the anatomical and functional sinus node. The funny current (I(f)) driven 'membrane clock' is not solely responsible for sinus node automaticity, following recent recognition of the importance of the 'calcium clock'. Several molecular links to sinus node remodeling have recently been identified: loss of connexin-43 expression and down-regulation of I(ca,L) in aging; reduced I(f) and down-regulation of I(f) encoding HCN4 and HCN2 subunits in heart failure; and calcium clock malfunction with down-regulated HCN4, HCN2 and minK in atrial fibrillation. SUMMARY Ongoing research with improved technology and techniques continues to unravel new understandings and challenges to the century old discovery of the anatomical sinus node.
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Stewart A, Huang J, Fisher RA. RGS Proteins in Heart: Brakes on the Vagus. Front Physiol 2012; 3:95. [PMID: 22685433 PMCID: PMC3368389 DOI: 10.3389/fphys.2012.00095] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/27/2012] [Indexed: 12/14/2022] Open
Abstract
It has been nearly a century since Otto Loewi discovered that acetylcholine (ACh) release from the vagus produces bradycardia and reduced cardiac contractility. It is now known that parasympathetic control of the heart is mediated by ACh stimulation of G(i/o)-coupled muscarinic M2 receptors, which directly activate G protein-coupled inwardly rectifying potassium (GIRK) channels via Gβγ resulting in membrane hyperpolarization and inhibition of action potential (AP) firing. However, expression of M2R-GIRK signaling components in heterologous systems failed to recapitulate native channel gating kinetics. The missing link was identified with the discovery of regulator of G protein signaling (RGS) proteins, which act as GTPase-activating proteins to accelerate the intrinsic GTPase activity of Gα resulting in termination of Gα- and Gβγ-mediated signaling to downstream effectors. Studies in mice expressing an RGS-insensitive Gα(i2) mutant (G184S) implicated endogenous RGS proteins as key regulators of parasympathetic signaling in heart. Recently, two RGS proteins have been identified as critical regulators of M2R signaling in heart. RGS6 exhibits a uniquely robust expression in heart, especially in sinoatrial (SAN) and atrioventricular nodal regions. Mice lacking RGS6 exhibit increased bradycardia and inhibition of SAN AP firing in response to CCh as well as a loss of rapid activation and deactivation kinetics and current desensitization for ACh-induced GIRK current (I(KACh)). Similar findings were observed in mice lacking RGS4. Thus, dysregulation in RGS protein expression or function may contribute to pathologies involving aberrant electrical activity in cardiac pacemaker cells. Moreover, RGS6 expression was found to be up-regulated in heart under certain pathological conditions, including doxorubicin treatment, which is known to cause life-threatening cardiotoxicity and atrial fibrillation in cancer patients. On the other hand, increased vagal tone may be cardioprotective in heart failure where acetylcholinesterase inhibitors and vagal stimulation have been proposed as potential therapeutics. Together, these studies identify RGS proteins, especially RGS6, as new therapeutic targets for diseases such as sick sinus syndrome or other maladies involving abnormal autonomic control of the heart.
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Affiliation(s)
- Adele Stewart
- Department of Pharmacology, Carver College of Medicine, University of Iowa Iowa City, IA, USA
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Abstract
Cardiac pacing has played a significant role in mitigating morbidity and mortality associated with bradyarrhythmias. Throughout the years, advances made in battery reliability, lead performance, and device portability have rapidly expanded the use of cardiac pacemakers in many different disease states. Despite the benefits, there has been growing awareness of the potential deleterious effects of long-term artificial electrical stimulation including the development of ventricular dyssynchrony and atrial fibrillation. Given their association with an increased risk for heart failure and possibly death, several advances aimed at minimizing them have been made in recent years including changes in atrioventricular pacing algorithms, novel pacing mode modifications, and better identification of hemodynamically optimal pacing sites. This article reviews the advances made and the future direction of innovations in cardiac pacing.
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Affiliation(s)
- Alan Cheng
- Department of Medicine, Division of Cardiology, Section of Cardiac Electrophysiology, Johns Hopkins Medical Institutes, Baltimore, MD, USA.
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Monfredi O, Dobrzynski H, Mondal T, Boyett MR, Morris GM. The anatomy and physiology of the sinoatrial node--a contemporary review. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:1392-406. [PMID: 20946278 DOI: 10.1111/j.1540-8159.2010.02838.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sinoatrial node is the primary pacemaker of the heart. Nodal dysfunction with aging, heart failure, atrial fibrillation, and even endurance athletic training can lead to a wide variety of pathological clinical syndromes. Recent work utilizing molecular markers to map the extent of the node, along with the delineation of a novel paranodal area intermediate in characteristics between the node and the surrounding atrial muscle, has shown that pacemaker tissue is more widely spread in the right atrium than previously appreciated. This can explain the phenomenon of a "wandering pacemaker" and concomitant changes in the P-wave morphology. Extensive knowledge now exists regarding the molecular architecture of the node (in particular, the expression of ion channels) and how this relates to pacemaking. This review is an up-to-date summary of the current state of our appreciation of the above topics.
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Affiliation(s)
- Oliver Monfredi
- Cardiovascular Medicine, Faculty of Medical and Human Sciences, University of Manchester, Core Technology Facility, Manchester, United Kingdom
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Jiang CX, Sang CH, Dong JZ, Liu XP, Long DY, Yu RH, Tang RB, Wu JH, Ning M, Liu C, Ma CS. Significant left atrial appendage activation delay complicating aggressive septal ablation during catheter ablation of persistent atrial fibrillation. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:652-60. [PMID: 20487359 DOI: 10.1111/j.1540-8159.2010.02753.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND This study aims to describe significant left atrial appendage activation following ablation of persistent atrial fibrillation, and explore its relationship with aggressive septal ablation. METHODS AND RESULTS Significant left atrial appendage activation delay was found in 23 out of 201 patients undergoing persistent atrial fibrillation ablation. Of them, 14 were found in their index procedures, of whom septal line ablation was performed in nine (odds ratio 15.2, 95% confidence interval 4.6-50.8, P < 0.001). Another nine were found during their redo procedures (including two with biatrial activation dissociation), all of whom received extensive left septal complex fractionated electrograms ablation in their prior procedures (P = 0.002). Electrocardiograph showed split P wave with the latter component merged into the QRS wave. Activation mapping demonstrated the earliest breakthrough of the left atrium changed to coronary sinus in 18 (85.7%) patients. After 1 month, the mitral A wave velocity was 18.2 +/- 17.0 cm/s, and decreased significantly as compared with preablation (20.2 +/- 19.1 vs 58.2 +/- 17.9 cm/s, P = 0.037) in patients undergoing redo procedures. Fourteen (60.9%) remained arrhythmia-free during follow-up for 10.6 +/- 6.2 months. CONCLUSION Septal line ablation and extensive septal complex fractionated electrograms ablation are correlated with significant left atrial activation delay or even biatrial activation dissociation, and should be performed with prudent consideration.
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Affiliation(s)
- Chen-Xi Jiang
- Department of Cardiology, Center for Atrial Fibrillation Center, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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John B, Stiles MK, Kuklik P, Brooks AG, Chandy ST, Kalman JM, Sanders P. Reverse remodeling of the atria after treatment of chronic stretch in humans: implications for the atrial fibrillation substrate. J Am Coll Cardiol 2010; 55:1217-1226. [PMID: 20298929 DOI: 10.1016/j.jacc.2009.10.046] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Revised: 10/22/2009] [Accepted: 10/26/2009] [Indexed: 10/19/2022]
Abstract
OBJECTIVES The aim of this report was to study the effect of chronic stretch reversal on the electrophysiological characteristics of the atria in humans. BACKGROUND Atrial stretch is an important determinant for atrial fibrillation. Whether relief of stretch reverses the substrate predisposed to atrial fibrillation is unknown. METHODS Twenty-one patients with mitral stenosis undergoing mitral commissurotomy (MC) were studied before and after intervention. Catheters were placed at multiple sites in the right atrium (RA) and sequentially within the left atrium (LA) to determine: effective refractory period (ERP) at 10 sites (600 and 450 ms) and P-wave duration (PWD). Bi-atrial electroanatomic maps determined conduction velocity (CV) and voltage. In 14 patients, RA studies were repeated >or=6 months after MC. RESULTS Immediately after MC, there was significant increase in mitral valve area (2.1 +/- 0.2 cm(2), p < 0.0001) with decrease in LA (23 +/- 7 mm Hg to 10 +/- 4 mm Hg, p < 0.0001) and pulmonary arterial pressures (38 +/- 16 mm Hg to 27 +/- 12 mm Hg, p < 0.0001) and LA volume (75 +/- 20 ml to 52 +/- 18 ml, p < 0.0001). This was associated with reduction in PWD (139 +/- 19 ms to 135 +/- 20 ms, p = 0.047), increase in CV (LA: 1.3 +/- 0.3 mm/ms to 1.7 +/- 0.2 mm/ms, p = 0.006; and RA: 1.0 +/- 0.1 mm/ms to 1.3 +/- 0.3 mm/ms, p = 0.002) and voltage (LA: 1.7 +/- 0.6 mV to 2.5 +/- 1.0 mV, p = 0.005; and RA: 1.8 +/- 0.6 mV to 2.2 +/- 0.7 mV, p = 0.09), and no change in ERP. Late after MC, mitral valve area remained at 2.1 +/- 0.3 cm(2) (p = 0.7) but with further decrease in PWD (113 +/- 19 ms, p = 0.04) and RA ERP (at 600 ms, p < 0.0001), with increase in CV (1.0 +/- 0.1 mm/ms to 1.3 +/- 0.2 mm/ms, p = 0.006) and voltage (1.8 +/- 0.7 mV to 2.8 +/- 0.6 mV, p = 0.002). CONCLUSIONS The atrial electrophysiologic and electroanatomic abnormalities that result from chronic stretch due to MS reverses after MC. These observations suggest that the substrate predisposing to atrial arrhythmias might be reversed.
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Affiliation(s)
- Bobby John
- Cardiovascular Research Center, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia; Department of Cardiology, Christian Medical College, Vellore, India
| | - Martin K Stiles
- Cardiovascular Research Center, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
| | - Pawel Kuklik
- Cardiovascular Research Center, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
| | - Anthony G Brooks
- Cardiovascular Research Center, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia
| | - Sunil T Chandy
- Department of Cardiology, Christian Medical College, Vellore, India
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital and the Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Prashanthan Sanders
- Cardiovascular Research Center, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia.
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STILES MARTINK, BROOKS ANTHONYG, ROBERTS-THOMSON KURTC, KUKLIK PAWEL, JOHN BOBBY, YOUNG GLENND, KALMAN JONATHANM, SANDERS PRASHANTHAN. High-Density Mapping of the Sinus Node in Humans: Role of Preferential Pathways and the Effect of Remodeling. J Cardiovasc Electrophysiol 2010; 21:532-9. [DOI: 10.1111/j.1540-8167.2009.01644.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Maraschiello MA, Redfearn DP, Baranchuk AM, Simpson CS. Right ventricular apical lead position is associated with prolonged signal-averaged P-wave duration. J Electrocardiol 2009; 42:561-5. [PMID: 19733859 DOI: 10.1016/j.jelectrocard.2009.07.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2009] [Indexed: 10/20/2022]
Abstract
AIM The study aimed to determine if right ventricular apical pacing is associated with adverse change in atrial substrate compared with right ventricular septal pacing. METHODS Patients with septal leads and dual-chamber devices with more than 3 months of follow-up and 70% or higher cumulative percentage of ventricular pacing were compared with a matched group of apically implanted leads with a cumulative percentage ventricular pacing of 70% or higher. Device parameters were recorded, and high-resolution recordings were obtained for signal-averaged P-wave (SAPW) analysis. Previously obtained SAPW recordings taken from 49 healthy patients and 73 patients with paroxysmal atrial fibrillation were used as negative and positive controls, respectively. RESULTS Ten patients with septal leads (mean age, 71.9 +/- 12.1 years; mean months implanted, 10.5 +/- 3.2 months) and 9 patients with apical leads (mean age, 71.9 +/- 5.7 years; mean months implanted, 11.4 +/- 6.4 months) were enrolled. The SAPW duration was longer in the apical cohort compared with the septal cohort (144.8 +/- 6.9 and 133.0 +/- 5.5 milliseconds, respectively; P = .001), whereas there was no significant difference between septal and normal cohorts (133.0 +/- 5.5 and 129.3 +/- 7.1 milliseconds, respectively; P = .08). CONCLUSIONS Apical pacing is associated with prolonged P-wave duration relative to septal pacing and controls: this may manifest as increased risk of atrial tachycardias and presents a potentially novel benefit of septal pacing.
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Affiliation(s)
- Mark A Maraschiello
- Arrhythmia Service, Queen's University, Kingston General Hospital, Kingston, Ontario, Canada
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Klein M, Klein N, Pfeiffer D. [Atrial pacing for prevention of atrial fibrillation. Influence of septal atrial pacing, atrial overdrive and AV-delay-optimization on atrial fibrillation burden]. Herzschrittmacherther Elektrophysiol 2009; 20:148-153. [PMID: 19756816 DOI: 10.1007/s00399-009-0057-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND Atrial overdrive and optimized interatrial conduction time can reduce atrial fibrillation (AF). Increased ventricular stimulation results in a higher incidence of atrial fibrillation. PATIENTS AND METHODS In 25 patients with paroxysmal AF, a dual-chamber pacemaker (Identity DR 5370, St. Jude Medical) was implanted. Atrial leads were placed randomly either septal (n=12) or conventional (n=13). Dynamic atrial overdrive (DAO) was activated and the AV delay was optimized according to Koglek's method. After 3, 6, 9, and 12 months automatic mode switch (AF burden) was analysed. RESULTS No difference in implantation parameters were observed between groups. Technical implantation parameters were in the normal range for both groups. After 12 months patients in the septal group had less AF burden (1% vs. 7%, p=0.06), and the total number of AF episodes was reduced. CONCLUSION Septal pacing is safe. In combination with DAO and AV delay optimization it may reduce the AF burden, which can be observed after 12 months.
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Affiliation(s)
- M Klein
- Abteilung Kardiologie/Angiologie, Universitätsklinikum Leipzig, Liebigstr. 20, 04103 Leipzig, Deutschland.
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Al Ghamdi B, Hassan W. Atrial Remodeling And Atrial Fibrillation: Mechanistic Interactions And Clinical Implications. J Atr Fibrillation 2009; 2:125. [PMID: 28496625 DOI: 10.4022/jafib.125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Revised: 12/19/2008] [Accepted: 04/14/2009] [Indexed: 01/13/2023]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. The prevalence of AF increases dramatically with age and is seen in as high as 9% of individuals by the age of 80 years. In high-risk patients, the thromboembolic stroke risk can be as high as 9% per year and is associated with a 2-fold increase in mortality. Although the pathophysiological mechanism underlying the genesis of AF has been the focus of many studies, it remains only partially understood. Conventional theories focused on the presence of multiple re-entrant circuits originating in the atria that are asynchronous and conducted at various velocities through tissues with various refractory periods. Recently, rapidly firing atrial activity in the muscular sleeves at the pulmonary veins ostia or inside the pulmonary veins have been described as potential mechanism,. AF results from a complex interaction between various initiating triggers and development of abnormal atrial tissue substrate. The development of AF leads to structural and electrical changes in the atria, a process known as remodeling. To have effective surgical or catheter ablation of AF good understanding of the possible mechanism(s) is crucial.Once initiated, AF alters atrial electrical and structural properties that promote its maintenance and recurrence. The role of atrial remodeling (AR) in the development and maintenance of AF has been the subject of many animal and human studies over the past 10-15 years. This review will discuss the mechanisms of AR, the structural, electrophysiologic, and neurohormonal changes associated with AR and it is role in initiating and maintaining AF. We will also discuss briefly the role of inflammation in AR and AF initiation and maintenance, as well as, the possible therapeutic interventions to prevent AR, and hence AF, based on the current understanding of the interaction between AF and AR.
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Affiliation(s)
- Bandar Al Ghamdi
- King Faisal Specialist Hospital and research centre, Riyadh, Saudi Arabia
| | - Walid Hassan
- King Faisal Specialist Hospital and research centre, Riyadh, Saudi Arabia
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Roberts-Thomson KC, Stevenson I, Kistler PM, Haqqani HM, Spence SJ, Goldblatt JC, Sanders P, Kalman JM. The role of chronic atrial stretch and atrial fibrillation on posterior left atrial wall conduction. Heart Rhythm 2009; 6:1109-17. [PMID: 19574109 DOI: 10.1016/j.hrthm.2009.04.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 04/06/2009] [Indexed: 12/13/2022]
Abstract
BACKGROUND The posterior left atrium (LA) is involved in the initiation and maintenance of atrial fibrillation (AF). OBJECTIVE The purpose of this study was to compare conduction patterns on the posterior LA in patients with mitral regurgitation (MR), with and without AF. METHODS Epicardial mapping of the posterior LA was performed in 23 patients undergoing cardiac surgery. Patients were included in one of three groups: Group A-patients in sinus rhythm with normal left ventricular function undergoing coronary artery bypass grafting, Group B-patients in sinus rhythm with MR undergoing mitral valve surgery, or Group C-patients in persistent AF with MR undergoing mitral valve surgery. Conduction patterns, regional conduction velocity, conduction heterogeneity, conduction anisotropy, and complex fractionated atrial electrograms (CFAEs) were assessed. RESULTS LA diameter was greater in patients in Groups C (57 +/- 4mm) and B (54 +/- 6mm) than in Group A (39 +/- 7 mm, P <0.01). Patients in Group C had a greater number of lines of conduction delay than Groups A and B (2.0 +/- 0.8 vs 1 +/- 0 and 1 +/- 0, P <0.05). The extent of conduction delay and conduction heterogeneity was greater in Group C than in Group B, which was greater than in Group A (P <0.05). The percentage of CFAEs that remained stable during AF was 61% +/- 17%. There was a significant correlation between CFAEs during AF and regions of slow conduction during pacing (R = 0.36, P <0.001). CONCLUSION Patients with MR, LA enlargement, and AF have more extensive regions of conduction slowing in the posterior LA. Anatomically constant lines of conduction delay in this region lead to circuitous wavefront propagation. During persistent AF, fractionated electrograms in the posterior LA are distributed to regions demonstrating slow conduction, and the majority remain stable over time.
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Affiliation(s)
- Kurt C Roberts-Thomson
- Department of Cardiology and Cardiothoracic Surgery, Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
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Roberts-Thomson KC, John B, Worthley SG, Brooks AG, Stiles MK, Lau DH, Kuklik P, Shipp NJ, Kalman JM, Sanders P. Left atrial remodeling in patients with atrial septal defects. Heart Rhythm 2009; 6:1000-6. [PMID: 19493703 DOI: 10.1016/j.hrthm.2009.03.050] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 03/25/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Information regarding left atrial (LA) substrate in conditions predisposing to atrial fibrillation (AF) is limited. OBJECTIVE This study sought to characterize the left atrial remodeling that results from chronic atrial stretch caused by atrial septal defect (ASD). METHODS Eleven patients with hemodynamically significant ASDs and 12 control subjects were studied. The following were evaluated using multipolar catheters: effective refractory period (ERP) at 7 sites, P-wave duration (PWD), conduction time, and inducibility of AF. LA electroanatomic maps were created to determine atrial activation, and regional conduction and voltage abnormalities. RESULTS Patients with ASDs showed significant LA enlargement (P <0.001), unchanged or prolonged atrial ERPs, increase in LA conduction times (P = 0.03), prolonged PWD (P <0.001), regional conduction slowing (P <0.001), greater number of double potentials or fractionated electrograms (P <0.0001), reduced atrial voltage (P <0.001), and more frequent electrical scar (P = 0.005) compared with control subjects. In addition, patients with ASDs showed a greater propensity for sustained AF with single extrastimuli (4 of 11 vs. 0 of 12, P = 0.04). CONCLUSION ASDs are associated with chronic left atrial stretch, which results in remodeling characterized by LA enlargement, loss of myocardium, and electrical scar that results in widespread conduction abnormalities but with no change or an increase in ERP. These abnormalities were associated with a greater propensity for sustained AF.
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Affiliation(s)
- Kurt C Roberts-Thomson
- Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital, University of Adelaide, Adelaide, Australia
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Blake GE, Lakkireddy D. Atrial Septal Defect and Atrial Fibrillation: The Known and Unknown. J Atr Fibrillation 2008; 1:45. [PMID: 28496588 DOI: 10.4022/jafib.45] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 05/19/2008] [Accepted: 08/25/2008] [Indexed: 11/10/2022]
Abstract
Atrial fibrillation (AF) is a common complication in patients with atrial septal defects (ASDs). The link between AF and ASD is fairly complex and entails modifications in electrophysiologic, contractile and structural properties, at the cellular and tissue level, of both atria, mainly due to chronic atrial stretch and dilation. Surgical repair or percutaneous closure of ASDs are equally effective in reducing mortality and symptoms but limited in preventing or curbing AF, unless combined with an arrhythmia-specific procedure. Transesophageal echocardiography (TEE) and intracardiac echocardiography (ICE) have improved the safety and success of the above procedures. Finally, clearer understanding of the pathophysiology of AF in patients with ASD (and CHF, in general) has led to target-specific advances in medical management.
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Affiliation(s)
- George E Blake
- Mid America Cardiology @ University of Kansas Hospital, Kansas City, KS
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Bhavnani SP, Coleman CI, White CM, Clyne CA, Yarlagadda R, Guertin D, Kluger J. Association between statin therapy and reductions in atrial fibrillation or flutter and inappropriate shock therapy. Europace 2008; 10:854-9. [DOI: 10.1093/europace/eun128] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Ninio DM, Saint DA. The role of stretch-activated channels in atrial fibrillation and the impact of intracellular acidosis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 97:401-16. [PMID: 18367236 DOI: 10.1016/j.pbiomolbio.2008.02.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The incidence of atrial fibrillation correlates with increasing atrial size. The electrical consequences of atrial stretch contribute to both the initiation and maintenance of atrial fibrillation. It is suggested that altered calcium handling and stretch-activated channel activity could explain the experimental findings of stretch-induced depolarisation, shortened refractoriness, slowed conduction and increased heterogeneity of refractoriness and conduction. Stretch-activated channel blocking agents protect against these pro-arrhythmic effects. Gadolinium, GsMTx-4 toxin and streptomycin prevent the stretch-related vulnerability to atrial fibrillation without altering the drop in refractory period associated with stretch. Changes the activity of two-pore K+ channels, which are sensitive to stretch and pH but not gadolinium, could underlie the drop in refractoriness. Intracellular acidosis induced with propionate amplified the change in refractoriness with stretch in the isolated rabbit heart model in keeping with the clinical observation of increased propensity to atrial fibrillation with acidosis. We propose that activation of non-specific cation stretch-activated channels provides the triggers for acute atrial fibrillation with high atrial pressure while activation of atrial two-pore K+ channels shortens atrial refractory period and increases heterogeneity of refractoriness, providing the substrate for atrial fibrillation to be sustained. Stretch-activated channel blockade represents an exciting target for future antiarrhythmic drugs.
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Affiliation(s)
- Daniel M Ninio
- Discipline of Physiology, School of Molecular & Biomedical Science, University of Adelaide, SA 5005, Australia
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Roberts-Thomson KC, Stevenson IH, Kistler PM, Haqqani HM, Goldblatt JC, Sanders P, Kalman JM. Anatomically Determined Functional Conduction Delay in the Posterior Left Atrium. J Am Coll Cardiol 2008; 51:856-62. [DOI: 10.1016/j.jacc.2007.11.037] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 10/29/2007] [Accepted: 11/08/2007] [Indexed: 11/29/2022]
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Tang M, Zhang S, Sun Q, Huang C. Alterations in electrophysiology and tissue structure of the left atrial posterior wall in a canine model of atrial fibrillation caused by chronic atrial dilatation. Circ J 2007; 71:1636-42. [PMID: 17895564 DOI: 10.1253/circj.71.1636] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Chronic left atrial dilatation (CDLA) is associated with an increased incidence of atrial fibrillation (AF). The electrophysiological functions of the left atrial posterior wall (LAPW) are not well understood. METHODS AND RESULTS Eight control dogs and 8 with CDLA (developed 6 months after partial mitral valve avulsion) were studied. An electrophysiological study was performed using the noncontact mapping system. The conduction velocity was significantly decreased in the LAPW in the CDLA group. During atrial extrastimulation, a sharp curvature in the activation wavefront became apparent in the LAPW of 6 CDLA dogs, with unidirectional block in 1 dog. The effective refractory periods increased homogeneously throughout the atrium in the CDLA group. AF was much more easily inducible in the CDLA dogs than in the controls. After the onset of AF, the LAPW exhibited the earliest disorganized activity as compared with other sites in the left atrial. In the CDLA dogs, the most extensive interstitial fibrosis was observed in the LAPW. CONCLUSIONS Alterations in the electrophysiologic properties and tissue structure of the LAPW were observed in the CDLA dogs. This study supports the idea that the LAPW may play a role in the mechanism of AF induced by CDLA.
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Affiliation(s)
- Min Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, Beijing, China
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