Electrocardiographic evidence of ventricular repolarization remodelling during atrial fibrillation.
OBJECTIVE
Some atrial fibrillation (AF) patients develop excessive QTc prolongation and torsade de pointes when they take QTc-prolonging antiarrhythmic drugs (class IA/III) immediately after termination of AF. We hypothesized that this is caused by changes in ventricular repolarization during AF. We aimed to establish whether such 'ventricular repolarization remodelling' occurs.


RESULTS
We studied all patients who visited our cardiac emergency room with AF and converted to sinus rhythm (SR) in a 30 months' period. We defined four groups: (i) no antiarrhythmic drugs, electrical cardioversion (n = 30), (ii) no antiarrhythmic drugs, spontaneous AF termination (n = 19), (iii) antiarrhythmic drugs, electrical cardioversion (n = 29), and (iv) antiarrhythmic drugs, spontaneous AF termination (n = 9). We studied QTc duration at SR before AF (SR(baseline)), immediately after termination of AF (SR(postAF)), and at follow-up (SR(followup): > or =7 days after SR(postAF)). Moreover, we studied determinants of QTc prolongation at SR(postAF). We found that, in all groups, QTc at SR(postAF) was significantly and transiently prolonged compared with SR(baseline). Although of limited magnitude on average (approximately 5%), the increase was substantial (approximately 15%) in some individuals. The only independent predictor of the magnitude of QTc prolongation was QTc duration at SR(baseline); this relation had a negative correlation.


CONCLUSIONS
AF causes ventricular repolarization remodelling, resulting in QTc prolongation. QTc prolongation is substantial in some patients and may render these patients vulnerable to pro-arrhythmia from class IA/III antiarrhythmic drugs immediately after termination of AF.
Tan
Hanno L
HL
Department of Clinical and Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. h.l.tan@amc.nl
Smits
Jeroen P P
JP
Loef
Arjan
A
Tanck
Michael W T
MW
Hardziyenka
Maxim
M
Campian
Maria E
ME
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000503:physiopathology* / Q000628:therapy; D003131:Combined Modality Therapy; D004554:Electric Countershock / Q000379:methods; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020257:Ventricular Remodeling / Q000502:physiology*
D000889:Anti-Arrhythmia Agents