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Watanabe T, Hachiya H, Watanabe H, Anno K, Okuyama T, Harunari T, Yokota A, Kamioka M, Komori T, Torigoe‐Kurosu Y, Makimoto H, Kabutoya T, Kimura Y, Imai Y, Kario K. Relationship between the atrial-activation pattern around the triangle of Koch and successful ablation sites in slow-fast atrioventricular nodal reentrant tachycardia. J Arrhythm 2024; 40:363-373. [PMID: 38586857 PMCID: PMC10995602 DOI: 10.1002/joa3.12999] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 12/28/2023] [Accepted: 01/20/2024] [Indexed: 04/09/2024] Open
Abstract
Background The precise details of atrial activation around the triangle of Koch (ToK) remain unknown. We evaluated the relationship between the atrial-activation pattern around the ToK and success sites for slow-pathway (SP) modification ablation in slow-fast atrioventricular reentrant tachycardia (AVNRT). Methods Thirty patients with slow-fast AVNRT who underwent successful ablation were enrolled. Atrial activation around the ToK during sinus rhythm was investigated using ultra-high-density mapping pre-ablation. The relationships among features of atrial-activation pattern and success sites were examined. Results Of 30 patients (22 cryoablation; 8 radiofrequency ablation), 26 patients had a collision site of two wavefronts of delayed atrial activation within ToK, indicating a success site. The activation-search function of Lumipoint software, which highlights only atrial activation with a spatiotemporal consistency, showed non-highlighted area on the tricuspid-annulus side of ToK. In 23 of the patients, a spiky potential was recorded at that collision site outside the Lumipoint-highlighted area. Fifteen cryoablation patients with a success site coincident with a collision site outside the Lumipoint-highlighted area had significantly more frequent disappearances of SP after initial cryoablation (46.7% vs. 0%, p = .029), fewer cryoablations (3.7 ± 1.8 vs. 5.3 ± 1.3, p = .045), and shorter procedure times (170 ± 57 vs. 228 ± 91 min, p = .082) compared to the seven cryoablation patients without such sites. Four patients had transient AV block by ablation inside the Lumipoint-highlighted area with fractionated signals, but no patient developed permanent AV block or recurrence post-procedure (median follow-up: 375 days). Conclusions SP modification ablation at the collision site of atrial activation of the tricuspid-annulus side along with a spiky potential could provide a better outcome.
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Affiliation(s)
- Tomonori Watanabe
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Hitoshi Hachiya
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
- Cardiovascular Center, Tsuchiura Kyodo HospitalIbarakiJapan
| | - Hiroaki Watanabe
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Kazunori Anno
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Takafumi Okuyama
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Tomohiko Harunari
- Division of Cardiovascular Medicine, Shin‐Oyama City HospitalTochigiJapan
| | - Ayako Yokota
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Masashi Kamioka
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Takahiro Komori
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Yuko Torigoe‐Kurosu
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Hisaki Makimoto
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Tomoyuki Kabutoya
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Yoshifumi Kimura
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Yasushi Imai
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
| | - Kazuomi Kario
- Division of Cardiovascular MedicineJichi Medical University School of MedicineTochigiJapan
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Pandozi C, Botto GL, Loricchio ML, D'Ammando M, Lavalle C, Del Giorno G, Matteucci A, Mariani MV, Nicolis D, Segreti L, Papa AA, Casale MC, Galeazzi M, Russo M, Di Belardino N, Pelargonio G, Centurion Aznaran C, Malacrida M, Maddaluno F, Treglia S, Piccolo F, Colivicchi F. High-density mapping of Koch's triangle during sinus rhythm and typical atrioventricular nodal re-entrant tachycardia, integrated with direct recording of atrio-ventricular node structure potential. J Cardiovasc Electrophysiol 2024; 35:379-388. [PMID: 38185855 DOI: 10.1111/jce.16168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/11/2023] [Accepted: 12/15/2023] [Indexed: 01/09/2024]
Abstract
BACKGROUND The mechanism of typical slow-fast atrioventricular nodal re-entrant tachycardia (AVNRT) and its anatomical and electrophysiological circuit inside the right atrium (RA) and Koch's Triangle (KT) are not well known. OBJECTIVE To identify the potentials of the compact AV node and inferior extensions and to perform accurate mapping of the RA and KT in sinus rhythm (SR) and during AVNRT, to define the tachycardia circuit. METHODS Consecutive patients with typical AVNRT were enrolled in 12 Italian centers and underwent mapping and ablation by means of a basket catheter with small electrode spacing for ultrahigh-density mapping and a modified signal-filtering toolset to record the potentials of the AV nodal structures. RESULTS Forty-five consecutive cases of successful ablation of typical slow-fast AVNRT were included. The mean SR cycle length (CL) was 784.1 ± 6 ms and the mean tachycardia CL was 361.2 ± 54 ms. The AV node potential had a significantly shorter duration and higher amplitude in sinus rhythm than during tachycardia (60 ± 40 ms vs. 160 ± 40 ms, p < .001 and 0.3 ± 0.2 mV vs. 0.09 ± 0.12 mV, p < .001, respectively). The nodal potential duration extension was 169.4 ± 31 ms, resulting in a time-window coverage of 47.6 ± 9%. The recording of AV nodal structure potentials enabled us to obtain 100% coverage of the tachycardia CL during slow-fast AVNRT. CONCLUSION Detailed recording of the potentials of nodal structures is possible by means of multipolar catheters for ultrahigh-density mapping, allowing 100% of the AVNRT CL to be covered. These results also have clinical implications for the ablation of right-septal and para-septal arrhythmias.
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Affiliation(s)
- Claudio Pandozi
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy
| | | | | | | | - Carlo Lavalle
- Azienda ospedaliero-universitaria Policlinico Umberto I, Rome, Italy
| | | | - Andrea Matteucci
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy
- Department of System and Experimental Medicine, University of Rome 'Tor Vergata, Rome, Italy
| | | | | | | | - Andrea Antonio Papa
- Cardiology and Syncope Unit, Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, Naples, Italy
| | | | - Marco Galeazzi
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy
| | - Maurizio Russo
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy
| | | | - Gemma Pelargonio
- Istituto di Cardiologia Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Cardiovascular Sciences, Arrhythmology Unit, Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, Italy
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Karlsson M, Platonov PG, Ulimoen SR, Sandberg F, Wallman M. Model-based estimation of AV-nodal refractory period and conduction delay trends from ECG. Front Physiol 2024; 14:1287365. [PMID: 38283279 PMCID: PMC10811553 DOI: 10.3389/fphys.2023.1287365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/18/2023] [Indexed: 01/30/2024] Open
Abstract
Introduction: Atrial fibrillation (AF) is the most common arrhythmia, associated with significant burdens to patients and the healthcare system. The atrioventricular (AV) node plays a vital role in regulating heart rate during AF by filtering electrical impulses from the atria. However, it is often insufficient in regards to maintaining a healthy heart rate, thus the AV node properties are modified using rate-control drugs. Moreover, treatment selection during permanent AF is currently done empirically. Quantifying individual differences in diurnal and short-term variability of AV-nodal function could aid in personalized treatment selection. Methods: This study presents a novel methodology for estimating the refractory period (RP) and conduction delay (CD) trends, and their uncertainty in the two pathways of the AV node during 24 h using non-invasive data. This was achieved by utilizing a network model together with a problem-specific genetic algorithm and an approximate Bayesian computation algorithm. Diurnal variability in the estimated RP and CD was quantified by the difference between the daytime and nighttime estimates, and short-term variability was quantified by the Kolmogorov-Smirnov distance between adjacent 10-min segments in the 24-h trends. Additionally, the predictive value of the derived parameter trends regarding drug outcome was investigated using several machine learning tools. Results: Holter electrocardiograms from 51 patients with permanent AF during baseline were analyzed, and the predictive power of variations in RP and CD on the resulting heart rate reduction after treatment with four rate control drugs was investigated. Diurnal variability yielded no correlation to treatment outcome, and no prediction of drug outcome was possible using the machine learning tools. However, a correlation between the short-term variability for the RP and CD in the fast pathway and resulting heart rate reduction during treatment with metoprolol (ρ = 0.48, p < 0.005 in RP, ρ = 0.35, p < 0.05 in CD) were found. Discussion: The proposed methodology enables non-invasive estimation of the AV node properties during 24 h, which-indicated by the correlation between the short-term variability and heart rate reduction-may have the potential to assist in treatment selection.
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Affiliation(s)
- Mattias Karlsson
- Department of Systems and Data Analysis, Fraunhofer-Chalmers Centre, Gothenburg, Sweden
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - Pyotr G. Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Sara R. Ulimoen
- Department of Medical Research, Vestre Viken Hospital Trust, Bærum Hospital, Drammen, Norway
| | - Frida Sandberg
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - Mikael Wallman
- Department of Systems and Data Analysis, Fraunhofer-Chalmers Centre, Gothenburg, Sweden
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Fontenla A, Tamargo J, Salgado R, López-Gil M, Mejía E, Matía R, Toquero J, Montilla I, Rajjoub EA, García-Fernandez FJ, Miracle A, Rey JR, Bueno H. Ivabradine for controlling heart rate in permanent atrial fibrillation: A translational clinical trial. Heart Rhythm 2023; 20:822-830. [PMID: 37245897 DOI: 10.1016/j.hrthm.2023.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 05/30/2023]
Abstract
BACKGROUND Pharmacological options for rate control in atrial fibrillation are scarce. Ivabradine was postulated to reduce the ventricular rate in this setting. OBJECTIVES The objectives of this study were to evaluate the mechanism of inhibition of atrioventricular conduction produced by ivabradine and to determine its efficacy and safety in atrial fibrillation. METHODS The effects of ivabradine on atrioventricular node and ventricular cells were studied by in vitro whole-cell patch-clamp experiments and mathematical simulation of human action potentials. In parallel, a multicenter, randomized, open-label, phase III clinical trial compared ivabradine with digoxin for uncontrolled permanent atrial fibrillation despite β-blocker or calcium channel blocker treatment. RESULTS Ivabradine 1 μM inhibited "funny" current and rapidly activating delayed rectifier potassium channel current by 28.9% and 22.8%, respectively (P < .05). The sodium channel current and L-type calcium channel current were reduced only at 10 μM. Ivabradine slowed the firing frequency of a modeled human atrioventricular node action potential by 10.6% and induced a minimal prolongation of ventricular action potential. Thirty-five (51.5%) patients were randomized to ivabradine and 33 (49.5%) to digoxin. The mean daytime heart rate decreased by 11.6 beats/min (-11.5%) in the ivabradine arm (P = .02) vs 19.6 (-20.6%) in the digoxin arm (P < .001), although the noninferiority margin of efficacy was not met (Z = -1.95; P = .97). The primary safety end point occurred in 3 patients (8.6%) on ivabradine and in 8 (24.2%) on digoxin (P = .10). CONCLUSION Ivabradine produced a moderate rate reduction in patients with permanent atrial fibrillation. The inhibition of funny current in the atrioventricular node seems to be the main mechanism responsible for this reduction. Compared with digoxin, ivabradine was less effective, was better tolerated, and had a similar rate of serious adverse events.
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Affiliation(s)
- Adolfo Fontenla
- Cardiology Department, Hospital Universitario Quironsalud Madrid, Madrid, Spain; Cardiology Department. Complejo Hospitalario Ruber Juan Bravo, Madrid, Spain; Research Institute Hospital Universitario 12 de Octubre (I+12), Madrid, Spain.
| | - Juan Tamargo
- Pharmacology and Toxicology Department, School of Medicine, Universidad Complutense de Madrid, Madrid Spain
| | - Ricardo Salgado
- Cardiology Department, Hospital Clínico Universitario San Carlos, Madrid, Spain
| | - María López-Gil
- Research Institute Hospital Universitario 12 de Octubre (I+12), Madrid, Spain
| | - Elena Mejía
- Cardiology Department, Hospital Universitario Rey Juan Carlos, Móstoles, Spain
| | - Roberto Matía
- Cardiology Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Jorge Toquero
- Cardiology Department, Hospital Universitario Puerta de Hierro, Majadahonda, Spain
| | - Isabel Montilla
- Cardiology Department, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain
| | - Ez-Alddin Rajjoub
- Research Institute Hospital Universitario 12 de Octubre (I+12), Madrid, Spain
| | | | - Angel Miracle
- Cardiology Department, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain
| | - Juan-Ramón Rey
- Cardiology Department, Hospital Universitario La Paz, Madrid, Spain
| | - Hector Bueno
- Research Institute Hospital Universitario 12 de Octubre (I+12), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Carlos III Health Institute, Madrid, Spain; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain; Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
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Ryzhii M, Ryzhii E. A compact multi-functional model of the rabbit atrioventricular node with dual pathways. Front Physiol 2023; 14:1126648. [PMID: 36969598 PMCID: PMC10036810 DOI: 10.3389/fphys.2023.1126648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 02/22/2023] [Indexed: 03/12/2023] Open
Abstract
The atrioventricular node (AVN) is considered a “black box”, and the functioning of its dual pathways remains controversial and not fully understood. In contrast to numerous clinical studies, there are only a few mathematical models of the node. In this paper, we present a compact, computationally lightweight multi-functional rabbit AVN model based on the Aliev-Panfilov two-variable cardiac cell model. The one-dimensional AVN model includes fast (FP) and slow (SP) pathways, primary pacemaking in the sinoatrial node, and subsidiary pacemaking in the SP. To obtain the direction-dependent conduction properties of the AVN, together with gradients of intercellular coupling and cell refractoriness, we implemented the asymmetry of coupling between model cells. We hypothesized that the asymmetry can reflect some effects related to the complexity of the real 3D structure of AVN. In addition, the model is accompanied by a visualization of electrical conduction in the AVN, revealing the interaction between SP and FP in the form of ladder diagrams. The AVN model demonstrates broad functionality, including normal sinus rhythm, AVN automaticity, filtering of high-rate atrial rhythms during atrial fibrillation and atrial flutter with Wenckebach periodicity, direction-dependent properties, and realistic anterograde and retrograde conduction curves in the control case and the cases of FP and SP ablation. To show the validity of the proposed model, we compare the simulation results with the available experimental data. Despite its simplicity, the proposed model can be used both as a stand-alone module and as a part of complex three-dimensional atrial or whole heart simulation systems, and can help to understand some puzzling functions of AVN.
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Affiliation(s)
- Maxim Ryzhii
- Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu, Japan
- *Correspondence: Maxim Ryzhii ,
| | - Elena Ryzhii
- Department of Anatomy and Histology, Fukushima Medical University, Fukushima, Japan
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Tchou P, Nemer D, Saliba W, Varma N, Aziz P, Patel A, Nakagawa H, Kanj M, Hussein A, Bhargava M, Wazni O. Junctional Tachycardia. JACC Clin Electrophysiol 2023; 9:425-441. [PMID: 36990601 DOI: 10.1016/j.jacep.2022.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/17/2022] [Accepted: 10/26/2022] [Indexed: 02/24/2023]
Abstract
Junctional tachycardia (JT) is typically considered to have an automatic mechanism originating from the distal atrioventricular node. When there is 1:1 retrograde conduction via the fast pathway, JT would resemble the typical form of atrioventricular nodal re-entrant tachycardia (AVNRT). Atrial pacing maneuvers have been proposed to exclude AVNRT and suggest a diagnosis of JT. However, after excluding AVNRT, one should consider the possibility of an infra-atrial narrow QRS re-entrant tachycardia, which can exhibit features that resemble AVNRT as well as JT. Pacing maneuvers and mapping techniques should be performed to assess for infra-atrial re-entrant tachycardia before concluding that JT is the mechanism of a narrow QRS tachycardia. Distinguishing JT from typical AVNRT or infra-atrial re-entrant tachycardia has notable implications regarding the approach to ablation of the tachycardia. Ultimately, a contemporary review of the evidence on JT raises some questions as to the mechanism and source of what has traditionally been considered JT.
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Pandozi C, Matteucci A, Galeazzi M, Russo M, Lavalle C, Ficili S, Malacrida M, Colivicchi F. New insights into atrioventricular nodal anatomy, physiology, and immunochemistry: A comprehensive review and a proposed model of the slow-fast atrioventricular nodal reentrant tachycardia circuit in agreement with direct potential recordings in the Koch's triangle area. Heart Rhythm 2023; 20:614-626. [PMID: 36634901 DOI: 10.1016/j.hrthm.2023.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023]
Abstract
Atrioventricular nodal reentrant tachycardia (AVNRT) is the most frequent regular tachycardia in humans. In this review, we describe the most recent discoveries regarding the anatomical, physiological, and molecular biological features of the atrioventricular junction that could underlie the typical slow-fast AVNRT mechanisms, as these insights could lead to the proposal of a new theory concerning the circuit of this arrhythmia. Despite several models have been proposed over the years, the precise anatomical site of the reentrant circuit and the pathway involved in the slow-fast AVNRT have not been conclusively defined. One possible way to evaluate all the hypotheses regarding the nodal tachycardia circuit in humans is to map this circuit. Thus, we tried to identify the slow potential of nodal and inferior extension structures by using automated mapping of atrial activation during both sinus rhythm and typical slow-fast AVNRT. This constitutes a first step toward the definition of nodal area activation in sinus rhythm and during slow-fast AVNRT. Further studies and technical improvements in recording the potentials of the atrioventricular node structures are necessary to confirm our initial results.
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Affiliation(s)
- Claudio Pandozi
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy.
| | | | - Marco Galeazzi
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy
| | - Maurizio Russo
- Division of Cardiology, San Filippo Neri Hospital, Rome, Italy
| | - Carlo Lavalle
- Department of Cardiovascular, Respiratory, Nephrological, Anesthesiological and Geriatric Sciences, "Sapienza" University of Rome, Rome, Italy
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Balawender K, Kłosowicz M, Inglot J, Pliszka A, Wawrzyniak A, Olszewska A, Clarke E, Golberg M, Smędra A, Barszcz K, Żytkowski A. Anatomical variants and clinical significance of atrioventricular bundle of His: A narrative review. Translational Research in Anatomy 2023. [DOI: 10.1016/j.tria.2023.100232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Kuzmin V, Ushenin KS, Dzhumaniiazova IV, Abramochkin D, Vornanen M. High temperature and hyperkalemia cause exit block of action potentials at the atrioventricular junction of rainbow trout (Oncorhynchus mykiss) heart. J Therm Biol 2022; 110:103378. [PMID: 36462845 DOI: 10.1016/j.jtherbio.2022.103378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 10/13/2022] [Accepted: 10/21/2022] [Indexed: 11/07/2022]
Abstract
At critically high temperatures, atrioventricular (AV) block causes ventricular bradycardia and collapse of cardiac output in fish. Here, the possible role of the AV canal in high temperature-induced heart failure was examined. To this end, optical mapping was used to measure action potential (AP) conduction in isolated AV junction preparations of the rainbow trout (Oncorhynchus mykiss) heart during acute warming/cooling in the presence of 4 or 8 mM external K+ concentration. The preparation included the AV canal and some atrial and ventricular tissue at its edges, and it was paced either from atrial or ventricular side at a frequency of 0.67 Hz (40 beats min-1) to trigger forward (anterograde) and backward (retrograde) conduction, respectively. The propagation of AP was fast in atrial and ventricular tissues, but much slower in the AV canal, causing an AV delay. Acute warming from 15 °C to 27 °C or cooling from 15 °C to 5 °C did not impair AP conduction in the AV canal, as both anterograde and retrograde excitations propagated regularly through the AV canal. In contrast, anterograde conduction through the AV canal did not trigger ventricular excitation at the boundary zone between the AV canal and the ventricle when extracellular K+ concentration was raised from 4 mM to 8 mM at 27 °C. Also, the retrograde conduction was blocked at the border between the AV canal and the atrium in high K+ at 27 °C. These findings suggest that the AV canal is resistant against high temperatures (and high K+), but the ventricular muscle cannot be excited by APs coming from the AV canal when temperature and external K+ concentration are simultaneously elevated. Therefore, bradycardia at high temperatures in fish may occur due to inability of AP of the AV canal to trigger ventricular AP at the junctional zone between the AV canal and the proximal part of the ventricle.
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Affiliation(s)
- Vladislav Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, building 12, Moscow, 119991, Russia.
| | - Konstantin S Ushenin
- Ural Federal University, Institute of Natural Sciences and Mathematics, Ekaterinburg, Kuybysheva Str., 48, Ekaterinburg, 620026, Russia
| | - Irina V Dzhumaniiazova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, building 12, Moscow, 119991, Russia
| | - Denis Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, building 12, Moscow, 119991, Russia; Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, Moscow, Russia; Department of Physiology, Pirogov Russian National Research Medical University, Ostrovitjanova 1, Moscow, 117997, Russia
| | - Matti Vornanen
- University of Eastern Finland, Department of Environmental and Biological Sciences, P.O.Box 111, 80101, Joensuu, Finland
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Plappert F, Wallman M, Abdollahpur M, Platonov PG, Östenson S, Sandberg F. An atrioventricular node model incorporating autonomic tone. Front Physiol 2022; 13:976468. [PMID: 36187793 PMCID: PMC9520409 DOI: 10.3389/fphys.2022.976468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/10/2022] [Indexed: 11/19/2022] Open
Abstract
The response to atrial fibrillation (AF) treatment is differing widely among patients, and a better understanding of the factors that contribute to these differences is needed. One important factor may be differences in the autonomic nervous system (ANS) activity. The atrioventricular (AV) node plays an important role during AF in modulating heart rate. To study the effect of the ANS-induced activity on the AV nodal function in AF, mathematical modelling is a valuable tool. In this study, we present an extended AV node model that incorporates changes in autonomic tone. The extension was guided by a distribution-based sensitivity analysis and incorporates the ANS-induced changes in the refractoriness and conduction delay. Simulated RR series from the extended model driven by atrial impulse series obtained from clinical tilt test data were qualitatively evaluated against clinical RR series in terms of heart rate, RR series variability and RR series irregularity. The changes to the RR series characteristics during head-down tilt were replicated by a 10% decrease in conduction delay, while the changes during head-up tilt were replicated by a 5% decrease in the refractory period and a 10% decrease in the conduction delay. We demonstrate that the model extension is needed to replicate ANS-induced changes during tilt, indicating that the changes in RR series characteristics could not be explained by changes in atrial activity alone.
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Affiliation(s)
- Felix Plappert
- Department of Biomedical Engineering, Lund University, Lund, Sweden
- *Correspondence: Felix Plappert,
| | - Mikael Wallman
- Department of Systems and Data Analysis, Fraunhofer-Chalmers Centre, Gothenburg, Sweden
| | | | - Pyotr G. Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Sten Östenson
- Department of Internal Medicine and Department of Clinical Physiology, Central Hospital Kristianstad, Kristianstad, Sweden
| | - Frida Sandberg
- Department of Biomedical Engineering, Lund University, Lund, Sweden
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Katritsis DG, Anderson RH. New Insights Into the Mechanisms of Fast and Slow Conduction in the Atrioventricular Node. Heart Rhythm 2022; 20:627-630. [PMID: 36049588 DOI: 10.1016/j.hrthm.2022.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022]
Affiliation(s)
| | - Robert H Anderson
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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Hassinen M, Dzhumaniiazova I, Abramochkin DV, Vornanen M. Ionic basis of atrioventricular conduction: ion channel expression and sarcolemmal ion currents of the atrioventricular canal of the rainbow trout (Oncorhynchus mykiss) heart. J Comp Physiol B 2021; 191:327-346. [PMID: 33575867 PMCID: PMC7895799 DOI: 10.1007/s00360-021-01344-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 12/15/2020] [Accepted: 01/18/2021] [Indexed: 12/17/2022]
Abstract
Atrioventricular (AV) nodal tissue synchronizes activities of atria and ventricles of the vertebrate heart and is also a potential site of cardiac arrhythmia, e.g., under acute heat stress. Since ion channel composition and ion currents of the fish AV canal have not been previously studied, we measured major cation currents and transcript expression of ion channels in rainbow trout (Oncorhynchus mykiss) AV tissue. Both ion current densities and expression of ion channel transcripts indicate that the fish AV canal has a characteristic electrophysiological phenotype that differs from those of sinoatrial tissue, atrium and ventricle. Two types of cardiomyocytes were distinguished electrophysiologically in trout AV nodal tissue: the one (transitional cell) is functionally intermediate between working atrial/ventricular myocytes and the other (AV nodal cell) has a less negative resting membrane potential than atrial and ventricular myocytes and is a more similar to the sinoatrial nodal cells in ion channel composition. The AV nodal cells are characterized by a small or non-existent inward rectifier potassium current (IK1), low density of fast sodium current (INa) and relatively high expression of T-type calcium channels (CACNA3.1). Pacemaker channel (HCN4 and HCN2) transcripts were expressed in the AV nodal tissue but If current was not found in enzymatically isolated nodal myocytes. The electrophysiological properties of the rainbow trout nodal cells are appropriate for a slow rate of action potential conduction (small INa) and a moderate propensity for pacemaking activity (absence of IK1).
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Affiliation(s)
- Minna Hassinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland
| | - Irina Dzhumaniiazova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia.,Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, Moscow, Russia.,Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101, Joensuu, Finland.
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Mahmud R, Jamal S. Effect of His bundle pacing on right bundle branch block located distal to site of pacing. J Electrocardiol 2020; 64:58-65. [PMID: 33341724 DOI: 10.1016/j.jelectrocard.2020.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/19/2020] [Accepted: 11/13/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND It is generally accepted that bundle branch block (BBB) may be corrected simply by selective His bundle pacing (S-HBP) distal to site of block. However, clinical HBP is often non-selective (NS), the site of block unknown and moving the HB lead is not always an option. Thus, while correction of right (R) BBB in NS-HBP has been reported, its mechanism is unknown. METHODS Threshold testing was done during His bundle pacing in 39 patients with RBBB. We compared NS-HBP and S-HBP and analyzed the role of pacing voltage and capture threshold of the parallel pathway, in partially or completely correcting RBBB. RESULTS During NS-HBP, higher pacing voltage completely corrected RBBB in 22/35 patients as compared to 5/18 patients at lower voltage. Remaining patients showed incomplete correction of RBBB. NS-HBP group with lower capture threshold of 1.3 ± 0.5 V completely resolved RBBB in 9/14 vs 3/11 patients in NS-S HBP group with higher capture threshold of 2.4 ± 0.8 V. QRS activation time in NSHBP was 91 ± 8 ms (baseline 97 ± 7 ms p = ns). S-HBP resolved RBBB in only 1/21 patients. CONCLUSIONS 1.) Lack of correction with S-HBP suggests that RBBB was distal to site of HBP and yet was corrected with NS-HBP. 2.) Voltage dependent correction of RBBB in NS-HBP suggests that conduction via a specialized parallel pathway maintains normal ventricular activation time. 3.) Correction of RBBB in all patients with NS-HBP, suggests that conduction block was either bypassed or right ventricular free wall pre-excited by conduction via parallel pathway.
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Affiliation(s)
- Rehan Mahmud
- McLaren Bay Region, 1900 Columbus Ave, Bay City, MI 48708, USA.
| | - Shakeel Jamal
- McLaren Bay Region, 1900 Columbus Ave, Bay City, MI 48708, USA.
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14
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Katritsis DG. A unified theory for the circuit of atrioventricular nodal re-entrant tachycardia. Europace 2020; 22:1763-1767. [DOI: 10.1093/europace/euaa196] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/17/2020] [Indexed: 01/04/2023] Open
Abstract
Abstract
Atrioventricular nodal re-entrant tachycardia (AVNRT) is the most common regular tachycardia in the human, but its exact circuit remains elusive. In this article, recent evidence about the electrophysiological characteristics of AVNRT and new data on the anatomy of the atrioventricular node, are discussed. Based on this information, a novel, unified theory for the nature of the circuit of the tachycardia is presented.
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Abstract
ABSTRACT
A mechanistic explanation for the tolerance limits of animals at high temperatures is still missing, but one potential target for thermal failure is the electrical signaling off cells and tissues. With this in mind, here I review the effects of high temperature on the electrical excitability of heart, muscle and nerves, and refine a hypothesis regarding high temperature-induced failure of electrical excitation and signal transfer [the temperature-dependent deterioration of electrical excitability (TDEE) hypothesis]. A central tenet of the hypothesis is temperature-dependent mismatch between the depolarizing ion current (i.e. source) of the signaling cell and the repolarizing ion current (i.e. sink) of the receiving cell, which prevents the generation of action potentials (APs) in the latter. A source–sink mismatch can develop in heart, muscles and nerves at high temperatures owing to opposite effects of temperature on source and sink currents. AP propagation is more likely to fail at the sites of structural discontinuities, including electrically coupled cells, synapses and branching points of nerves and muscle, which impose an increased demand of inward current. At these sites, temperature-induced source–sink mismatch can reduce AP frequency, resulting in low-pass filtering or a complete block of signal transmission. In principle, this hypothesis can explain a number of heat-induced effects, including reduced heart rate, reduced synaptic transmission between neurons and reduced impulse transfer from neurons to muscles. The hypothesis is equally valid for ectothermic and endothermic animals, and for both aquatic and terrestrial species. Importantly, the hypothesis is strictly mechanistic and lends itself to experimental falsification.
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Affiliation(s)
- Matti Vornanen
- Department of Environmental and Biological Sciences , University of Eastern Finland, 80101 Joensuu, Finland
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16
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Reiffel JA. The high road, the low road, and no road: She took them all. J Electrocardiol 2020; 60:175-6. [PMID: 32388338 DOI: 10.1016/j.jelectrocard.2020.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/15/2020] [Accepted: 04/26/2020] [Indexed: 11/22/2022]
Abstract
A 42-year old female with no significant past medical history, normal physical exam, and normal routine lab studies presents with "thumps" in her chest. A Holter monitor evaluation revealed normal sinus rhythm with two different PR intervals suggesting "dual AV nodal pathways" and occasional blocked P waves with junctional escape complexes. The behavior was most suggestive that no conduction through either pathway reached the His bundle, suggesting distal block must be beyond each pathway, but still within the AV node. These strips are shown. Their interpretation is discussed, along with the underlying explanation and significance.
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17
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Abstract
Cardiac electrophysiology has progressed in great strides since the electrical activity of the heart was first discovered in 1842 and documented using electrocardiography. Optical imaging of cardiac electrophysiology, or optocardiography, has seen many advances in recent years including panoramic imaging of the heart, alternating transillumination to image transmural electrical activity, optogenetic models and customizable 3D printed optical mapping systems. Most of these techniques were adopted from other fields of study and refined for cardiac electrophysiology purposes. The future of this field could see similar adaptations of photoacoustic tomography, structured light technology and optical coherence tomography contributing to optocardiography.
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18
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Billette J, Tadros R. An integrated overview of AV node physiology. Pacing Clin Electrophysiol 2019; 42:805-820. [DOI: 10.1111/pace.13734] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/10/2019] [Accepted: 05/27/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Jacques Billette
- Département de Physiologie, Faculté de MédecineUniversité de Montréal Montréal Canada
| | - Rafik Tadros
- Département de Physiologie, Faculté de MédecineUniversité de Montréal Montréal Canada
- Electrophysiology ServiceMontreal Heart Institute Montreal Canada
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Bhattacharyya S, Duan J, Wang L, Li B, Bhakta M, Fernandez-Perez A, Hon GC, Munshi NV. Using Gjd3-CreEGFP mice to examine atrioventricular node morphology and composition. Sci Rep 2019; 9:2106. [PMID: 30765799 PMCID: PMC6375990 DOI: 10.1038/s41598-019-38683-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
The atrioventricular node (AVN) coordinates the timing of atrial and ventricular contraction to optimize cardiac performance. To study this critical function using mouse genetics, however, new reagents are needed that allow AVN-specific manipulation. Here we describe a novel Gjd3-CreEGFP mouse line that successfully recombines floxed alleles within the AVN beginning at E12.5. These mice have been engineered to express CreEGFP under the control of endogenous Gjd3 regulatory elements without perturbing native protein expression. Detailed histological analysis of Gjd3-CreEGFP mice reveals specific labeling of AVN cardiomyocytes and a subset of cardiac endothelial cells. Importantly, we show that Gjd3-CreEGFP mice have preserved cardiac mechanical and electrical function. In one application of our newly described mouse line, we provide a three-dimensional (3D) view of the AVN using tissue clearing combined with confocal microscopy. With this 3D model as a reference, we identify specific AVN sub-structures based on marker staining characteristics. In addition, we use our Gjd3-CreEGFP mice to guide microdissection of the AVN and construction of a single-cell atlas. Thus, our results establish a new transgenic tool for AVN-specific recombination, provide an updated model of AVN morphology, and describe a roadmap for exploring AVN cellular heterogeneity.
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Affiliation(s)
- Samadrita Bhattacharyya
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jialei Duan
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Lin Wang
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Boxun Li
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Minoti Bhakta
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Antonio Fernandez-Perez
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Gary C Hon
- Laboratory of Regulatory Genomics, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.,Hamon Center for Regenerative Science and Medicine, Dallas, TX, 75390, USA
| | - Nikhil V Munshi
- Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA. .,Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, 75390, USA. .,McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, 75390, USA. .,Hamon Center for Regenerative Science and Medicine, Dallas, TX, 75390, USA.
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Stephenson RS, Rowley-Nobel J, Jones CB, Guerrero R, Lowe T, Zhao J, Zhang H, Jarvis JC. Morphological Substrates for Atrial Arrhythmogenesis in a Heart With Atrioventricular Septal Defect. Front Physiol 2018; 9:1071. [PMID: 30190677 PMCID: PMC6115687 DOI: 10.3389/fphys.2018.01071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Due to advances in corrective surgery, congenital heart disease has an ever growing patient population. Atrial arrhythmias are frequently observed pre- and post-surgical correction. Pharmaceutical antiarrhythmic therapy is not always effective, therefore many symptomatic patients undergo catheter ablation therapy. In patients with atrioventricular septal defects (AVSD), ablation therapy itself has mixed success; arrhythmogenic recurrences are common, and because of the anatomical displacement of the atrioventricular node, 3-degree heart block post-ablation is a real concern. In order to develop optimal and safe ablation strategies, the field of congenital cardiac electrophysiology must combine knowledge from clinical electrophysiology with a thorough understanding of the anatomical substrates for arrhythmias. Using image-based analysis and multi-cellular mathematical modeling of electrical activation, we show how the anatomical alterations characteristic of an AVSD serve as arrhythmogenic substrates. Using ex-vivo contrast enhanced micro-computed tomography we imaged post-mortem the heart of a 5 month old male with AVSD at an isometric spatial resolution of 38 μm. Morphological analysis revealed the 3D disposition of the cardiac conduction system for the first time in an intact heart with this human congenital malformation. We observed displacement of the compact atrioventricular node inferiorly to the ostium of the coronary sinus. Myocyte orientation analysis revealed that the normal arrangement of the major atrial muscle bundles was preserved but was modified in the septal region. Models of electrical activation suggest the disposition of the myocytes within the atrial muscle bundles associated with the "fast pathway," together with the displaced atrioventricular node, serve as potential substrates for re-entry and possibly atrial fibrillation. This study used archived human hearts, showing them to be a valuable resource for the mathematical modeling community, and opening new possibilities for the investigations of arrhythmogenesis and ablation strategies in the congenitally malformed heart.
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Affiliation(s)
- Robert S Stephenson
- Comparative Medicine Lab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jack Rowley-Nobel
- School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Caroline B Jones
- Department of Cardiology, Alder Hey Children's Hospital, Liverpool, United Kingdom
| | - Rafael Guerrero
- Department of Cardiac Surgery, Alder Hey Children's Hospital, Liverpool, United Kingdom
| | - Tristan Lowe
- Manchester X-ray Imaging Facility, Photon Science Institute, University of Manchester, Manchester, United Kingdom
| | - Jichao Zhao
- Auckland Bioengineering Institute, Auckland University, Auckland, New Zealand
| | - Henggui Zhang
- School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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21
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Markowitz SM, Lerman BB. A contemporary view of atrioventricular nodal physiology. J Interv Card Electrophysiol 2018; 52:271-279. [DOI: 10.1007/s10840-018-0392-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 05/31/2018] [Indexed: 11/30/2022]
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23
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Kokladi M. Unravelling the Mysteries of the Human AV Node. Arrhythm Electrophysiol Rev 2018; 7:63. [DOI: 10.15420/aer.2018.7.1.l1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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