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O'Reilly M, Sommerfeld LC, O'Shea C, Broadway-Stringer S, Andaleeb S, Reyat JS, Kabir SN, Stastny D, Malinova A, Delbue D, Fortmueller L, Gehmlich K, Pavlovic D, Skryabin BV, Holmes AP, Kirchhof P, Fabritz L. Familial atrial fibrillation mutation M1875T-SCN5A increases early sodium current and dampens the effect of flecainide. Europace 2022; 25:1152-1161. [PMID: 36504385 PMCID: PMC10062360 DOI: 10.1093/europace/euac218] [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: 07/15/2022] [Accepted: 10/23/2022] [Indexed: 12/14/2022] Open
Abstract
AIMS Atrial fibrillation (AF) is the most common cardiac arrhythmia. Pathogenic variants in genes encoding ion channels are associated with familial AF. The point mutation M1875T in the SCN5A gene, which encodes the α-subunit of the cardiac sodium channel Nav1.5, has been associated with increased atrial excitability and familial AF in patients. METHODS AND RESULTS We designed a new murine model carrying the Scn5a-M1875T mutation enabling us to study the effects of the Nav1.5 mutation in detail in vivo and in vitro using patch clamp and microelectrode recording of atrial cardiomyocytes, optical mapping, electrocardiogram, echocardiography, gravimetry, histology, and biochemistry. Atrial cardiomyocytes from newly generated adult Scn5a-M1875T+/- mice showed a selective increase in the early (peak) cardiac sodium current, larger action potential amplitude, and a faster peak upstroke velocity. Conduction slowing caused by the sodium channel blocker flecainide was less pronounced in Scn5a-M1875T+/- compared to wildtype atria. Overt hypertrophy or heart failure in Scn5a-M1875T+/- mice could be excluded. CONCLUSION The Scn5a-M1875T point mutation causes gain-of-function of the cardiac sodium channel. Our results suggest increased atrial peak sodium current as a potential trigger for increased atrial excitability.
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Affiliation(s)
- Molly O'Reilly
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK.,Department of Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Laura C Sommerfeld
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK.,University Center of Cardiovascular Science, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany.,DZHK Standort Hamburg/Kiel/Luebeck, Martinistraße 52, Hamburg 20246, Germany
| | - C O'Shea
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - S Broadway-Stringer
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - S Andaleeb
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - J S Reyat
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - S N Kabir
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - D Stastny
- University Center of Cardiovascular Science, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany
| | - A Malinova
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - D Delbue
- University Center of Cardiovascular Science, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany.,DZHK Standort Hamburg/Kiel/Luebeck, Martinistraße 52, Hamburg 20246, Germany
| | - L Fortmueller
- University Center of Cardiovascular Science, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany.,DZHK Standort Hamburg/Kiel/Luebeck, Martinistraße 52, Hamburg 20246, Germany
| | - K Gehmlich
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK.,Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, UK
| | - D Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK
| | - B V Skryabin
- Medical Faculty, Core Facility Transgenic animal and genetic engineering Models (TRAM), University of Muenster, Muenster, Germany
| | - A P Holmes
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK.,Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| | - P Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK.,DZHK Standort Hamburg/Kiel/Luebeck, Martinistraße 52, Hamburg 20246, Germany.,Department of Cardiology, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany
| | - L Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Wolfson Drive, Birmingham B15 2TT, UK.,University Center of Cardiovascular Science, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany.,DZHK Standort Hamburg/Kiel/Luebeck, Martinistraße 52, Hamburg 20246, Germany.,Department of Cardiology, University Heart and Vascular Center, UKE Hamburg, Martinistraße 52, Hamburg 20246, Germany
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2
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Van Steenkiste G, Carlson J, Decloedt A, Vera L, Buhl R, Platonov PG, van Loon G. Relationship between atrial fibrillatory rate based on analysis of a modified base-apex surface electrocardiogram analysis and the results of transvenous electrical cardioversion in horses with spontaneous atrial fibrillation. J Vet Cardiol 2021; 34:73-79. [PMID: 33611234 DOI: 10.1016/j.jvc.2021.01.001] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 12/31/2020] [Accepted: 01/05/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To compare the atrial fibrillatory rate (AFR) derived from a local right atrial intracardiac recording (RA-FR) and from a single-lead surface electrocardiogram (ECG) during atrial fibrillation (AF) and to evaluate the correlation with transvenous electrical cardioversion (TVEC) threshold (in Joules), number of shocks and cardioversion success rate in horses. ANIMALS ECGs and clinical records of horses with AF treated by TVEC. Horses were included if a simultaneous recording of the right atrial intracardiac electrogram and a modified base-apex ECG were available. MATERIALS AND METHODS Clinical records of horses with AF treated by TVEC were reviewed. Three-minute long episodes of simultaneous electrograms and surface ECG during AF were selected for analysis and compared using Bland-Altman analysis. The mean RA-FR was measured from the deflections on the intracardiac electrogram, while the AFR was extracted from the surface ECG using spatiotemporal QRS and T-wave cancellation. RESULTS Seventy-three horses satisfied the inclusion criteria. The mean difference between RA-FR and AFR was -13 fibrillations per minute (fpm), the 95% limits of agreement were between -66 and 40 fpm, and there was a moderate (ρ = 0.65) correlation between RA-FR and AFR (p < 0.001). Neither RA-FR nor AFR appeared to influence the TVEC cardioversion threshold or the number of TVEC shocks applied. CONCLUSIONS The AFR may allow non-invasive long-term monitoring of AF dynamics. Neither RA-FR nor AFR could be used to predict the minimal defibrillation threshold for TVEC.
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Affiliation(s)
- G Van Steenkiste
- Equine Cardioteam, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - J Carlson
- Department of Cardiology, Lund University, 21185 Lund, Sweden
| | - A Decloedt
- Equine Cardioteam, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - L Vera
- Equine Cardioteam, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - R Buhl
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Højbakkegaard Allé 5, 2630 Taastrup, Denmark
| | - P G Platonov
- Arrhythmia Clinic, Skåne University Hospital and Department of Cardiology, Clinical Sciences, Lund University, 21185 Lund, Sweden
| | - G van Loon
- Equine Cardioteam, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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3
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Fastl TE, Tobon-Gomez C, Crozier A, Whitaker J, Rajani R, McCarthy KP, Sanchez-Quintana D, Ho SY, O'Neill MD, Plank G, Bishop MJ, Niederer SA. Personalized computational modeling of left atrial geometry and transmural myofiber architecture. Med Image Anal 2018; 47:180-190. [PMID: 29753182 PMCID: PMC6277816 DOI: 10.1016/j.media.2018.04.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [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: 07/26/2017] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 01/15/2023]
Abstract
Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by complete absence of coordinated atrial contraction and is associated with an increased morbidity and mortality. Personalized computational modeling provides a novel framework for integrating and interpreting the role of atrial electrophysiology (EP) including the underlying anatomy and microstructure in the development and sustenance of AF. Coronary computed tomography angiography data were segmented using a statistics-based approach and the smoothed voxel representations were discretized into high-resolution tetrahedral finite element (FE) meshes. To estimate the complex left atrial myofiber architecture, individual fiber fields were generated according to morphological data on the endo- and epicardial surfaces based on local solutions of Laplace’s equation and transmurally interpolated to tetrahedral elements. The influence of variable transmural microstructures was quantified through EP simulations on 3 patients using 5 different fiber interpolation functions. Personalized geometrical models included the heterogeneous thickness distribution of the left atrial myocardium and subsequent discretization led to high-fidelity tetrahedral FE meshes. The novel algorithm for automated incorporation of the left atrial fiber architecture provided a realistic estimate of the atrial microstructure and was able to qualitatively capture all important fiber bundles. Consistent maximum local activation times were predicted in EP simulations using individual transmural fiber interpolation functions for each patient suggesting a negligible effect of the transmural myofiber architecture on EP. The established modeling pipeline provides a robust framework for the rapid development of personalized model cohorts accounting for detailed anatomy and microstructure and facilitates simulations of atrial EP.
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Affiliation(s)
- Thomas E Fastl
- Department of Biomedical Engineering, King's College London, London, United Kingdom.
| | - Catalina Tobon-Gomez
- Department of Biomedical Engineering, King's College London, London, United Kingdom
| | - Andrew Crozier
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - John Whitaker
- Department of Biomedical Engineering, King's College London, London, United Kingdom; Department of Cardiology, Guy's and St Thomas' Hospitals, London, United Kingdom
| | - Ronak Rajani
- Department of Biomedical Engineering, King's College London, London, United Kingdom; Department of Cardiology, Guy's and St Thomas' Hospitals, London, United Kingdom
| | - Karen P McCarthy
- Cardiac Morphology Unit, Royal Brompton Hospital, London, United Kingdom
| | | | - Siew Y Ho
- Cardiac Morphology Unit, Royal Brompton Hospital, London, United Kingdom
| | - Mark D O'Neill
- Department of Biomedical Engineering, King's College London, London, United Kingdom; Department of Cardiology, Guy's and St Thomas' Hospitals, London, United Kingdom
| | - Gernot Plank
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - Martin J Bishop
- Department of Biomedical Engineering, King's College London, London, United Kingdom
| | - Steven A Niederer
- Department of Biomedical Engineering, King's College London, London, United Kingdom
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4
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Hesselkilde EZ, Carstensen H, Haugaard MM, Carlson J, Pehrson S, Jespersen T, Buhl R, Platonov PG. Effect of flecainide on atrial fibrillatory rate in a large animal model with induced atrial fibrillation. BMC Cardiovasc Disord 2017; 17:289. [PMID: 29221440 PMCID: PMC5723027 DOI: 10.1186/s12872-017-0720-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [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: 06/15/2017] [Accepted: 11/24/2017] [Indexed: 11/25/2022] Open
Abstract
Background Atrial fibrillatory cycle length has been considered one of the indices of atrial electrical remodelling during atrial fibrillation (AF), which can be assessed from surface ECG by computer-assisted calculation of atrial fibrillatory rate (AFR). Horses have been suggested as a bona fide model for AF studies since horses too, develop lone AF, however data on AF characteristics in horses are extremely sparse and non-invasive characterization of AF complexity using surface ECG processing has not been reported. Aim The aim was to study characteristics of induced AF and its modification by flecainide. Methods The study group consisted on 3 horses with spontaneous persistent AF and 13 with pace-induced AF. Seven horses were treated with saline (control) and eight with flecainide (2 mg/kg). ECGs were analysed using spatiotemporal cancellation of QRST complexes and calculation of AFR from the residual atrial signal. Results At AF onset, AFR was 295 ± 52 fibrillations per minute (fpm) in the horses with induced AF treated with flecainide, 269 ± 36 fpm in the control group (ns), and 364 ± 26 fpm in the horses with spontaneous persistent AF (P < 0.05 compared to the control group). Flecainide caused a decrease in AFR in all animals and restored sinus rhythm in the animals with induced AF. In the control animals, AFR increased from 269 ± 36 fpm to a plateau of 313 ± 14 fpm before decreasing to 288 ± 28 fpm during the last 10% of the AF episodes preceding spontaneous conversion (P < 0.05). Conclusion AFR in horses with induced AF resembles AFR in humans with paroxysmal AF. Flecainide caused a rapid decrease in AFR in all horses, further supporting the method to be a non-invasive technique to study the effect of antiarrhythmic compounds.
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Affiliation(s)
- Eva Z Hesselkilde
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Højbakkegaard Allé 5, 2630, Taastrup, Denmark
| | - Helena Carstensen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Højbakkegaard Allé 5, 2630, Taastrup, Denmark
| | - Maria M Haugaard
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Højbakkegaard Allé 5, 2630, Taastrup, Denmark
| | - Jonas Carlson
- Department of Cardiology, Lund University, 21185, Lund, Sweden
| | - Steen Pehrson
- Department of Cardiology, The Heart Centre, University of Copenhagen, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Rikke Buhl
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Højbakkegaard Allé 5, 2630, Taastrup, Denmark.
| | - Pyotr G Platonov
- Arrhythmia Clinic, Skåne University Hospital and Department of Cardiology, Clinical Sciences, Lund University, 21185, Lund, Sweden
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5
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Petersson R, Smith JG, Larsson DA, Reitan Ö, Carlson J, Platonov P, Holmqvist F. Orthogonal P-wave morphology is affected by intra-atrial pressures. BMC Cardiovasc Disord 2017; 17:288. [PMID: 29212469 PMCID: PMC5719760 DOI: 10.1186/s12872-017-0724-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/28/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND It has previously been shown that the morphology of the P-wave neither depends on atrial size in healthy subjects with physiologically enlarged atria nor on the physiological anatomical variation in transverse orientation of the left atrium. The present study aimed to investigate if different pressures in the left and right atrium are associated with different P-wave morphologies. METHODS 38 patients with isolated, increased left atrial pressure, 51 patients with isolated, increased right atrial pressure and 76 patients with biatrially increased pressure were studied. All had undergone right heart catheterization and had 12-lead electrocardiographic recordings, which were transformed into vectorcardiograms for detailed P-wave morphology analysis. RESULTS Normal P-wave morphology (type 1) was more common in patients with isolated increased pressure in the right atrium while abnormal P-wave morphology (type 2) was more common in the groups with increased left atrial pressure (P = 0.032). Moreover, patients with increased left atrial pressure, either isolated or in conjunction with increased right atrial pressure, had significantly more often a P-wave morphology with a positive deflection in the sagittal plane (P = 0.004). CONCLUSION Isolated elevated right atrial pressure was associated with normal P-wave morphology while left-sided atrial pressure elevation, either isolated or in combination with right atrial pressure elevation, was associated with abnormal P-wave morphology.
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Affiliation(s)
- Richard Petersson
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
- Center for Integrative Electrocardiology, Lund University, Lund, Sweden
| | - J. Gustav Smith
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
- Heart Failure and Valvular Disease Clinic, Skåne University Hospital, Lund, Sweden
| | - David A. Larsson
- Department of Internal and Emergency Medicine, Skåne University Hospital, Lund, Sweden
| | - Öyvind Reitan
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
- Heart Failure and Valvular Disease Clinic, Skåne University Hospital, Lund, Sweden
| | - Jonas Carlson
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
- Center for Integrative Electrocardiology, Lund University, Lund, Sweden
| | - Pyotr Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
- Center for Integrative Electrocardiology, Lund University, Lund, Sweden
- Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden
| | - Fredrik Holmqvist
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
- Center for Integrative Electrocardiology, Lund University, Lund, Sweden
- Arrhythmia Clinic, Skåne University Hospital, Lund, Sweden
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Jacquemet V. Equivalent dipole sources to estimate the influence of extracellular myocardial anisotropy in thin-walled cardiac forward models. Math Biosci 2017; 286:31-38. [PMID: 28159543 DOI: 10.1016/j.mbs.2017.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 07/29/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
Abstract
The extracellular domain of the heart is anisotropic, which affects volume conduction and therefore body surface potentials. This paper tests the hypothesis that when wall thickness is sufficiently small (such as in the atria), the effect of extracellular anisotropy can be estimated by modifying local dipole current sources. A formula based on the Gabor-Nelson equivalent dipole and on the reciprocity theorem is derived to compute a linear transformation of the dipole sources that approximates in an isotropic volume conductor the far-field of the actual sources in an anisotropic volume conductor. It involves solving three Poisson equation (once for all). The results obtained in an atrial model embedded in a boundary-element torso model suggest that when wall thickness is < 3 mm, simulated P waves are weakly altered by extracellular anisotropy during sinus rhythm: an anisotropy ratio of 4:1 typically reduced the longitudinal component of the dipole sources by < 3%, increased the transverse component by < 5%, and increased the transmural component by ≈ 25% (which may be relevant in case of epicardial-endocardial dissociation). Due to uncertainty on experimental conductivity values, it is proposed that atrial extracellular anisotropy may be neglected when computing P waves.
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Affiliation(s)
- Vincent Jacquemet
- Université de Montréal, Département de Pharmacologie et Physiologie, Institut de Génie Biomédical, Montréal, Canada; Hôpital du Sacré-Coeur de Montréal, Centre de Recherche, 5400 boul. Gouin Ouest, Montréal, H4J 1C5, Canada.
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Haugaard MM, Hesselkilde EZ, Pehrson S, Carstensen H, Flethøj M, Præstegaard KF, Sørensen US, Diness JG, Grunnet M, Buhl R, Jespersen T. Pharmacologic inhibition of small-conductance calcium-activated potassium (SK) channels by NS8593 reveals atrial antiarrhythmic potential in horses. Heart Rhythm 2014; 12:825-35. [PMID: 25542425 DOI: 10.1016/j.hrthm.2014.12.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [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: 10/22/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Small-conductance calcium-activated potassium (SK) channels have been found to play an important role in atrial repolarization and atrial fibrillation (AF). OBJECTIVE The purpose of this study was to investigate the existence and functional role of SK channels in the equine heart. METHODS Cardiac biopsies were analyzed to investigate the expression level of the most prominent cardiac ion channels, with special focus on SK channels, in the equine heart. Subcellular distribution of SK isoform 2 (SK2) was assessed by immunohistochemistry and confocal microscopy. The electrophysiologic and anti-AF effects of the relative selective SK channel inhibitor NS8593 (5 mg/kg IV) were evaluated in anesthetized horses, focusing on the potential of NS8593 to terminate acute pacing-induced AF, drug-induced changes in atrial effective refractory period, AF duration and vulnerability, and ventricular depolarization and repolarization times. RESULTS Analysis revealed equivalent mRNA transcript levels of the 3 SK channel isoforms in atria compared to ventricles. Immunohistochemistry and confocal microscopy displayed a widespread distribution of SK2 in both atrial and ventricular cardiomyocytes. NS8593 terminated all induced AF episodes (duration ≥15 minutes), caused pronounced prolongation of atrial effective refractory period, and reduced AF duration and vulnerability. QRS duration and QTc interval were not affected by treatment. CONCLUSION SK channels are widely distributed in atrial and ventricular cardiomyocytes and contribute to atrial repolarization. Inhibition by NS8593 terminates pacing-induced AF of short duration and decreases AF duration and vulnerability without affecting ventricular conduction and repolarization. Thus, inhibition by NS8593 demonstrates clear atrial antiarrhythmic properties in healthy horses.
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Affiliation(s)
- Maria Mathilde Haugaard
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Eva Zander Hesselkilde
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steen Pehrson
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Taastrup, Denmark
| | - Helena Carstensen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Flethøj
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kirstine Færgemand Præstegaard
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | - Rikke Buhl
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Danish National Foundation Research Centre in Arrhythmias (DARC) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Wang X, Huang C, Zhao Q, Huang H, Tang Y, Dai Z, Wang X, Guo Z, Xiao J. Effect of renal sympathetic denervation on the progression of paroxysmal atrial fibrillation in canines with long-term intermittent atrial pacing. Europace 2014; 17:647-54. [PMID: 25349225 DOI: 10.1093/europace/euu212] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [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: 03/25/2014] [Accepted: 07/03/2014] [Indexed: 11/13/2022] Open
Abstract
AIMS The aim of the present study was to explore the effect of renal sympathetic denervation (RSD) on the progression of paroxysmal atrial fibrillation (AF) in canines with long-term intermittent atrial pacing. METHODS AND RESULTS Nineteen beagles were randomly divided into sham-operated group (six dogs), control group (six dogs), and RSD group (seven dogs). Sham-operated group were implanted with pacemakers without pacing; control group were implanted with pacemakers with long-term intermittent atrial pacing; and RSD group underwent catheter-based RSD bilaterally and were simultaneously implanted with pacemakers. Atrial pacing was maintained for 8 h a day and a total of 12 weeks in the control group and RSD group. Echocardiography showed that the left atrial structure and function were significantly improved in the RSD group compared with the control group (P < 0.05). Compared with the control group, the RSD group had fewer incidences of AF and a shorter duration of AF (P < 0.05) after long-term intermittent atrial pacing. In addition to increased atrial effective refractory period (AERP) and AF cycle length, AERP dispersion and P-wave duration and dispersion were significantly decreased in the RSD group compared with the control group (P < 0.05). Atrial morphological evaluation suggested that fibrosis and ultrastructural changes induced by long-term intermittent atrial pacing were markedly suppressed in the RSD dogs compared with controls (P < 0.05). Immunohistochemistry results showed that connexin 43 distribution in RSD mid-myocardial was significantly fewer heterogeneous than that in control mid-myocardial (P < 0.05). CONCLUSION Renal denervation inhibits the progression of paroxysmal AF, which might be related to the suppression of atrial electrophysiology and structural heterogeneity.
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Affiliation(s)
- Xule Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Qingyan Zhao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - He Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Yanhong Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Zixuan Dai
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Xiaozhan Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Zongwen Guo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
| | - Jinping Xiao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan City 430060, People's Republic of China Cardiovascular Research Institute of Wuhan University, Wuhan City 430060, People's Republic of China
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9
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Haugaard MM, Pehrson S, Carstensen H, Flethøj M, Hesselkilde EZ, Praestegaard KF, Diness JG, Grunnet M, Jespersen T, Buhl R. Antiarrhythmic and electrophysiologic effects of flecainide on acutely induced atrial fibrillation in healthy horses. J Vet Intern Med 2014; 29:339-47. [PMID: 25328012 PMCID: PMC4858114 DOI: 10.1111/jvim.12496] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [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: 05/02/2014] [Revised: 09/02/2014] [Accepted: 10/02/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Only few pharmacologic compounds have been validated for treatment of atrial fibrillation (AF) in horses. Studies investigating the utility and safety of flecainide to treat AF in horses have produced conflicting results, and the antiarrhythmic mechanisms of flecainide are not fully understood. OBJECTIVES To study the potential of flecainide to terminate acutely induced AF of short duration (≥ 15 minutes), to examine flecainide-induced changes in AF duration and AF vulnerability, and to investigate the in vivo effects of flecainide on right atrial effective refractory period, AF cycle length, and ventricular depolarization and repolarization. ANIMALS Nine Standardbred horses. Eight received flecainide, 3 were used as time-matched controls, 2 of which also received flecainide. METHODS Prospective study. The antiarrhythmic and electrophysiologic effects of flecainide were based on 5 parameters: ability to terminate acute pacing-induced AF (≥ 15 minutes), and drug-induced changes in atrial effective refractory period, AF duration, AF vulnerability, and ventricular depolarization and repolarization times. Parameters were assessed at baseline and after flecainide by programmed electrical stimulation methods. RESULTS Flecainide terminated all acutely induced AF episodes (n = 7); (AF duration, 21 ± 5 minutes) and significantly decreased the AF duration, but neither altered atrial effective refractory period nor AF vulnerability significantly. Ventricular repolarization time was prolonged between 8 and 20 minutes after initiation of flecainide infusion, but no ventricular arrhythmias were detected. CONCLUSIONS AND CLINICAL IMPORTANCE Flecainide had clear antiarrhythmic properties in terminating acute pacing-induced AF, but showed no protective properties against immediate reinduction of AF. Flecainide caused temporary prolongation in the ventricular repolarization, which may be a proarrhythmic effect.
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Affiliation(s)
- M M Haugaard
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
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