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Knecht S, Schlageter V, Badertscher P, Krisai P, Jousset F, Küffer T, Madaffari A, Schaer B, Osswald S, Sticherling C, Kühne M. Atrial substrate characterization based on bipolar voltage electrograms acquired with multipolar, focal and mini-electrode catheters. Europace 2023; 25:euad127. [PMID: 37165671 PMCID: PMC10228606 DOI: 10.1093/europace/euad127] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023] Open
Abstract
BACKGROUND Bipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration. AIMS The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four catheters with different electrode design and to identify their specific LA cutoffs for scar and healthy tissue. METHODS AND RESULTS Consecutive high-resolution electroanatomic mapping was performed using a multipolar-minielectrode Orion catheter (Orion-map), a duo-decapolar circular mapping catheter (Lasso-map), and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3 × 3 × 3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1, 0.2, 0.5, 1.0, and 1.5 mV. We analyzed 25 patients (72% men, age 68 ± 15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 and 2.21 mV, respectively. CONCLUSION When measuring LA BVA, significant differences were seen between focal, multielectrode, and minielectrode catheters. Adapted cutoffs for scar and healthy tissue are required for different catheters.
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Affiliation(s)
- Sven Knecht
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Vincent Schlageter
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Patrick Badertscher
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Philipp Krisai
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Florian Jousset
- Boston Scientific, Rhythm Management, Solothurn, Switzerland
| | - Thomas Küffer
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Antonio Madaffari
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Beat Schaer
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Stefan Osswald
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Christian Sticherling
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Michael Kühne
- Department of Cardiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031 Basel, Switzerland
- Cardiovascular Research Institute Basel, University Hospital Basel, University of Basel, Basel, Switzerland
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Johner N, Shah DC, Jousset F, Dall’Aglio PB, Namdar M. Electrophysiological and Anatomical Correlates of Sites With Postpacing Intervals Shorter Than Tachycardia Cycle Length in Atypical Atrial Flutter. Circ Arrhythm Electrophysiol 2019; 12:e006955. [DOI: 10.1161/circep.118.006955] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nicolas Johner
- Cardiology Division, University Hospitals of Geneva (N.J., D.C.S., P.B.D., M.N.)
| | - Dipen C. Shah
- Cardiology Division, University Hospitals of Geneva (N.J., D.C.S., P.B.D., M.N.)
| | - Florian Jousset
- Boston Scientific, Rhythm Management, Solothurn, Switzerland (F.J.)
| | | | - Mehdi Namdar
- Cardiology Division, University Hospitals of Geneva (N.J., D.C.S., P.B.D., M.N.)
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Salvarani N, Maguy A, De Simone SA, Miragoli M, Jousset F, Rohr S. TGF-β 1 (Transforming Growth Factor-β 1) Plays a Pivotal Role in Cardiac Myofibroblast Arrhythmogenicity. Circ Arrhythm Electrophysiol 2017; 10:e004567. [PMID: 28500173 DOI: 10.1161/circep.116.004567] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [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: 08/04/2016] [Accepted: 03/16/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND TGF-β1 (transforming growth factor-β1) importantly contributes to cardiac fibrosis by controlling differentiation, migration, and collagen secretion of cardiac myofibroblasts. It is still elusive, however, to which extent TGF-β1 alters the electrophysiological phenotype of myofibroblasts and cardiomyocytes and whether it affects proarrhythmic myofibroblast-cardiomyocyte crosstalk observed in vitro. METHODS AND RESULTS Patch-clamp recordings of cultured neonatal rat ventricular myofibroblasts revealed that TGF-β1, applied for 24 to 48 hours at clinically relevant concentrations (≤2.5 ng/mL), causes substantial membrane depolarization concomitant with a several-fold increase of transmembrane currents. Transcriptome analysis revealed TGF-β1-dependent changes in 29 of 63 ion channel/pump/connexin transcripts, indicating a pleiotropic effect on the electrical phenotype of myofibroblasts. Whereas not affecting cardiomyocyte membrane potentials and cardiomyocyte-cardiomyocyte gap junctional coupling, TGF-β1 depolarized cardiomyocytes coupled to myofibroblasts by ≈20 mV and increased gap junctional coupling between myofibroblasts and cardiomyocytes >5-fold as reflected by elevated connexin 43 and consortin transcripts. TGF-β1-dependent cardiomyocyte depolarization resulted from electrotonic crosstalk with myofibroblasts as demonstrated by immediate normalization of cardiomyocyte electrophysiology after targeted disruption of coupled myofibroblasts and by cessation of ectopic activity of cardiomyocytes coupled to myofibroblasts during pharmacological gap junctional uncoupling. In cardiac fibrosis models exhibiting slow conduction and ectopic activity, block of TGF-β1 signaling completely abolished both arrhythmogenic conditions. CONCLUSIONS TGF-β1 profoundly alters the electrophysiological phenotype of cardiac myofibroblasts. Apart from possibly contributing to the control of cell function in general, the changes proved to be pivotal for proarrhythmic myofibroblast-cardiomyocyte crosstalk in vitro, which suggests that TGF-β1 may play a potentially important role in arrhythmogenesis of the fibrotic heart.
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Affiliation(s)
- Nicolò Salvarani
- From the Department of Physiology, University of Bern, Switzerland
| | - Ange Maguy
- From the Department of Physiology, University of Bern, Switzerland
| | | | - Michele Miragoli
- From the Department of Physiology, University of Bern, Switzerland
| | - Florian Jousset
- From the Department of Physiology, University of Bern, Switzerland
| | - Stephan Rohr
- From the Department of Physiology, University of Bern, Switzerland.
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Jousset F, Maguy A, Rohr S, Kucera JP. Myofibroblasts Electrotonically Coupled to Cardiomyocytes Alter Conduction: Insights at the Cellular Level from a Detailed In silico Tissue Structure Model. Front Physiol 2016; 7:496. [PMID: 27833567 PMCID: PMC5081362 DOI: 10.3389/fphys.2016.00496] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 07/28/2016] [Accepted: 10/11/2016] [Indexed: 01/05/2023] Open
Abstract
Fibrotic myocardial remodeling is typically accompanied by the appearance of myofibroblasts (MFBs). In vitro, MFBs were shown to slow conduction and precipitate ectopic activity following gap junctional coupling to cardiomyocytes (CMCs). To gain further mechanistic insights into this arrhythmogenic MFB-CMC crosstalk, we performed numerical simulations in cell-based high-resolution two-dimensional tissue models that replicated experimental conditions. Cell dimensions were determined using confocal microscopy of single and co-cultured neonatal rat ventricular CMCs and MFBs. Conduction was investigated as a function of MFB density in three distinct cellular tissue architectures: CMC strands with endogenous MFBs, CMC strands with coating MFBs of two different sizes, and CMC strands with MFB inserts. Simulations were performed to identify individual contributions of heterocellular gap junctional coupling and of the specific electrical phenotype of MFBs. With increasing MFB density, both endogenous and coating MFBs slowed conduction. At MFB densities of 5-30%, conduction slowing was most pronounced in strands with endogenous MFBs due to the MFB-dependent increase in axial resistance. At MFB densities >40%, very slow conduction and spontaneous activity was primarily due to MFB-induced CMC depolarization. Coating MFBs caused non-uniformities of resting membrane potential, which were more prominent with large than with small MFBs. In simulations of MFB inserts connecting two CMC strands, conduction delays increased with increasing insert lengths and block appeared for inserts >1.2 mm. Thus, electrophysiological properties of engineered CMC-MFB co-cultures depend on MFB density, MFB size and their specific positioning in respect to CMCs. These factors may influence conduction characteristics in the heterocellular myocardium.
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Affiliation(s)
- Florian Jousset
- Department of Physiology, University of Bern Bern, Switzerland
| | - Ange Maguy
- Department of Physiology, University of Bern Bern, Switzerland
| | - Stephan Rohr
- Department of Physiology, University of Bern Bern, Switzerland
| | - Jan P Kucera
- Department of Physiology, University of Bern Bern, Switzerland
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Syeda F, Holmes AP, Yu TY, Tull S, Kuhlmann SM, Pavlovic D, Betney D, Riley G, Kucera JP, Jousset F, de Groot JR, Rohr S, Brown NA, Fabritz L, Kirchhof P. PITX2 Modulates Atrial Membrane Potential and the Antiarrhythmic Effects of Sodium-Channel Blockers. J Am Coll Cardiol 2016; 68:1881-1894. [PMID: 27765191 PMCID: PMC5075046 DOI: 10.1016/j.jacc.2016.07.766] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 07/05/2016] [Accepted: 07/20/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Antiarrhythmic drugs are widely used to treat patients with atrial fibrillation (AF), but the mechanisms conveying their variable effectiveness are not known. Recent data suggested that paired like homeodomain-2 transcription factor (PITX2) might play an important role in regulating gene expression and electrical function of the adult left atrium (LA). OBJECTIVES After determining LA PITX2 expression in AF patients requiring rhythm control therapy, the authors assessed the effects of Pitx2c on LA electrophysiology and the effect of antiarrhythmic drugs. METHODS LA PITX2 messenger ribonucleic acid (mRNA) levels were measured in 95 patients undergoing thoracoscopic AF ablation. The effects of flecainide, a sodium (Na+)-channel blocker, and d,l-sotalol, a potassium channel blocker, were studied in littermate mice with normal and reduced Pitx2c mRNA by electrophysiological study, optical mapping, and patch clamp studies. PITX2-dependent mechanisms of antiarrhythmic drug action were studied in human embryonic kidney (HEK) cells expressing human Na channels and by modeling human action potentials. RESULTS Flecainide 1 μmol/l was more effective in suppressing atrial arrhythmias in atria with reduced Pitx2c mRNA levels (Pitx2c+/-). Resting membrane potential was more depolarized in Pitx2c+/- atria, and TWIK-related acid-sensitive K+ channel 2 (TASK-2) gene and protein expression were decreased. This resulted in enhanced post-repolarization refractoriness and more effective Na-channel inhibition. Defined holding potentials eliminated differences in flecainide's effects between wild-type and Pitx2c+/- atrial cardiomyocytes. More positive holding potentials replicated the increased effectiveness of flecainide in blocking human Nav1.5 channels in HEK293 cells. Computer modeling reproduced an enhanced effectiveness of Na-channel block when resting membrane potential was slightly depolarized. CONCLUSIONS PITX2 mRNA modulates atrial resting membrane potential and thereby alters the effectiveness of Na-channel blockers. PITX2 and ion channels regulating the resting membrane potential may provide novel targets for antiarrhythmic drug development and companion therapeutics in AF.
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Affiliation(s)
- Fahima Syeda
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew P Holmes
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ting Y Yu
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Physical Sciences of Imaging in the Biomedical Sciences, School of Chemistry, University of Birmingham, Birmingham, United Kingdom
| | - Samantha Tull
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | | | - Davor Pavlovic
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Daniel Betney
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Genna Riley
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jan P Kucera
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Florian Jousset
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Joris R de Groot
- Heart Center, Department of Cardiology, Academisch Medisch Centrum, Amsterdam, the Netherlands
| | - Stephan Rohr
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Nigel A Brown
- St. George's Hospital Medical School, University of London, London, United Kingdom
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany; Atrial Fibrillation NETwork, Muenster, Germany; University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany; Atrial Fibrillation NETwork, Muenster, Germany; University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom; Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, United Kingdom.
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Dirkx E, Perea Gil I, Li MC, Gupta SK, Nguyen THM, Syeda F, Dirkx E, Raso A, Braga L, Zentilin L, Zacchigna S, Giacca M, De Windt LJ, Prat-Vidal C, Galvez-Monton C, Roura S, Llucia-Valldeperas A, Soler-Botija C, Diaz-Guemes I, Crisostomo V, Sanchez-Margallo FM, Bayes-Genis A, Cimino J, De Santis MC, Pianca N, Sciarretta S, Sandri M, Zaglia T, Mongillo M, Hirsch E, Ghigo A, Bauters C, De Groote P, Foinquinos A, Boon R, De Windt LJ, Batkai S, Pinet F, Thum T, Choquet C, Kober F, Bernard M, Kelly RG, Miquerol L, Lalevee N, Holmes A, Yu T, Tull S, Kuhlmann S, Pavlovic D, Betney D, Riley G, Kucera JP, Jousset F, De Groot J, Rohr S, Brown N, Fabritz L, Kirchhof P. Young Investigator Award Session - Heart40Targeting the miRNA-106b-25 cluster as a potential regenerative therapeutic approach for myocardial injury41An allogeneic bioengineered myocardial graft limits infarct size and improves cardiac function: pre-clinical study in the porcine myocardial infarction model42Phosphoinositide 3-kinase gamma inhibition protects against anthracycline-induced cardiomyopathy by boosting cardiac autophagy43Functional screening of microRNAs identifies miR-22 as a regulator of cardiac autophagy and aging44Functional defects and molecular mechanisms of left ventricular non-compaction in nkx2.5 mutant mice45PITX2 modulates atrial membrane potential, potentiating the antiarrhythmic effects of sodium channel blockers. Cardiovasc Res 2016. [DOI: 10.1093/cvr/cvw139] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Syeda F, Holmes AP, Yu TY, Tull SP, Riley G, Jousset F, Kucera J, Rohr S, Fabritz L, Kirchhof P. 169 PITX2C deficiency augments the anti-arrhythmic properties of flecainide: results in a mouse model and validation in a human atrium simulation study. Heart 2015. [DOI: 10.1136/heartjnl-2015-308066.169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Jousset F, Rohr S. Optical recording of calcium currents during impulse conduction in cardiac tissue. Neurophotonics 2015; 2:021011. [PMID: 26158001 PMCID: PMC4478756 DOI: 10.1117/1.nph.2.2.021011] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 01/08/2015] [Indexed: 06/04/2023]
Abstract
We explore the feasibility of obtaining a spatially resolved picture of [Formula: see text] inward currents ([Formula: see text]) in multicellular cardiac tissue by differentiating optically recorded [Formula: see text] transients that accompany propagating action potentials. Patterned growth strands of neonatal rat ventricular cardiomyocytes were stained with the [Formula: see text] indicators Fluo-4 or Fluo-4FF. Preparations were stimulated at 1 Hz, and [Formula: see text] transients were recorded with high spatiotemporal resolution ([Formula: see text], 2 kHz analog bandwidth) with a photodiode array. Signals were differentiated after appropriate digital filtering. Differentiation of [Formula: see text] transients resulted in optically recorded calcium currents (ORCCs) that carried the temporal and pharmacological signatures of L-type [Formula: see text] inward currents: the time to peak amounted to [Formula: see text] (Fluo-4FF) and [Formula: see text] (Fluo-4), full-width at half-maximum was [Formula: see text], and ORCCs were completely suppressed by [Formula: see text][Formula: see text]. Also, and as reported before from patch-clamp studies, caffeine reversibly depressed the amplitude of ORCCs. The results demonstrate that the differentiation of [Formula: see text] transients can be used to obtain a spatially resolved picture of the initial phase of [Formula: see text] in cardiac tissue and to assess relative changes of activation/fast inactivation of [Formula: see text] following pharmacological interventions.
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Affiliation(s)
- Florian Jousset
- University of Bern, Department of Physiology, Bühlplatz 5, CH-3012 Bern, Switzerland
| | - Stephan Rohr
- University of Bern, Department of Physiology, Bühlplatz 5, CH-3012 Bern, Switzerland
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Jousset F, Grand T, Rohr S, Kucera JP. Changes of Axial Resistance following Mechanical Strain Prevail Over Stretch-Activated Currents in the Modulation of Conduction Velocity in Cardiac Cell Strands. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1587] [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: 11/24/2022] Open
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Jousset F, Tenkorang J, Vesin JM, Pascale P, Ruchat P, Rollin AG, Fromer M, Narayan SM, Pruvot E. Kinetics of atrial repolarization alternans in a free-behaving ovine model. J Cardiovasc Electrophysiol 2012; 23:1003-12. [PMID: 22554055 DOI: 10.1111/j.1540-8167.2012.02336.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UNLABELLED Kinetics of Atrial Repolarization Alternans. INTRODUCTION Repolarization alternans (Re-ALT), a beat-to-beat alternation in action potential repolarization, promotes dispersion of repolarization, wavebreaks, and reentry. Recently, Re-ALT has been shown to play an important role in the transition from rapid pacing to atrial fibrillation (AF) in humans. The detailed kinetics of atrial Re-ALT, however, has not been reported so far. We developed a chronic free-behaving ovine pacing model to study the kinetics of atrial Re-ALT as a function of pacing rate. METHODS Thirteen sheep were chronically implanted with 2 pacemakers for the recording of broadband right atrial unipolar electrograms and delivery of rapid pacing protocols. Beat-to-beat differences in the atrial T-wave apex amplitude as a measure of Re-ALT and activation time were analyzed at incremental pacing rates until the effective refractory period (ERP) defined as stable 2:1 capture. RESULTS Atrial Re-ALT appeared intermittently but without periodicity, and increased in amplitude as a function of pacing rate until ERP. Intermittent 2:1 atrial capture was observed at pacing cycle lengths 40 ms above ERP, and increased in duration as a function of pacing rate. Episodes of rapid pacing-induced AF were rare, and were preceded by Re-ALT or complex oscillations of atrial repolarization, but without intermittent capture. CONCLUSION We show in vivo that atrial Re-ALT developed and increased in magnitude with rate until stable 2:1 capture. In rare instances where capture failure did not occur, Re-ALT and complex oscillations of repolarization surged and preceded AF initiation. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1003-1012, September 2012).
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Affiliation(s)
- Florian Jousset
- Applied Signal Processing Group, Swiss Federal Institute of Technology, Lausanne, Switzerland
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Pruvot E, Jousset F, Ruchat P, Vesin JM, Prudat Y, Zerm T, Fromer M. Propagation velocity kinetics and repolarization alternans in a free-behaving sheep model of pacing-induced atrial fibrillation. Europace 2008; 9 Suppl 6:vi83-8. [PMID: 17959698 DOI: 10.1093/europace/eum211] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Experimental models have reported conflicting results regarding the role of dispersion of repolarization in promoting atrial fibrillation (AF). Repolarization alternans, a beat-to-beat alternation in action potential duration, enhances dispersion of repolarization when propagation velocity is involved. METHODS AND RESULTS In this work, original electrophysiological parameters were analysed to study AF susceptibility in a chronic sheep model of pacing-induced AF. Two pacemakers were implanted, each with a single right atrial lead. Right atrial depolarization and repolarization waves were documented at 2-week intervals. A significant and gradual decrease in the propagation velocity at all pacing rates and in the right atrial effective refractory period (ERP) was observed during the weeks of burst pacing before sustained AF developed when compared with baseline conditions. Right atrial repolarization alternans was observed, but because of the development of 2/1 atrioventricular block with far-field ventricular interference, its threshold could not be precisely measured. Non-sustained AF was not observed at baseline, but appeared during the electrical remodelling in association with a decrease in both ERP and propagation velocity. CONCLUSION We report here on the feasibility of measuring ERP, atrial repolarization alternans, and propagation velocity kinetics and their potential in predicting susceptibility to AF in a free-behaving model of pacing-induced AF using the standard pacemaker technology.
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Affiliation(s)
- Etienne Pruvot
- Service of Cardiology, BH10-982, CHUV, Rue du Bugnon 46M, 1011 Lausanne, Switzerland.
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