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Ventricular Proarrhythmic Effects of Atrial Fibrillation are Modulated by Depolarization and Repolarization Anomalies in Patients with Left Ventricular Dysfunction
Author(s) -
LEMOLA KRISTINA,
KHAN RAZI,
NATTEL STANLEY,
TALAJIC MARIO,
ROY DENIS,
GUERRA PETER G.,
LEMOLA SAKARI,
DUBUC MARC,
THIBAULT BERNARD,
MACLE LAURENT,
KHAIRY PAUL
Publication year - 2009
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2009.02182.x
Subject(s) - medicine , cardiology , hazard ratio , qrs complex , atrial fibrillation , ejection fraction , implantable cardioverter defibrillator , proportional hazards model , qt interval , repolarization , ventricular fibrillation , heart failure , confidence interval , electrophysiology
Background: Atrial fibrillation (AF) may have a ventricular proarrhythmic effect, particularly in the setting of heart failure. We assessed whether AF predicts appropriate implantable cardioverter‐defibrillator (ICD) shocks in patients with left ventricular dysfunction and explored modulators of risk.Methods and Results: A retrospective cohort study was conducted on 215 consecutive patients with ICDs for primary prevention having a left ventricular ejection fraction ≤ 35%. Mean age at ICD implantation was 61.0 ± 9.7 years and 17% were women. Overall, 22 patients (10.2%) experienced appropriate ICD shocks over a follow‐up of 1.3 ± 0.7 years, corresponding to an actuarial event‐rate of 5.8% per year. In univariate analysis, AF was associated with a 3.6‐fold increased risk of appropriate shocks (P = 0.0037). Annual rates of appropriate ICD shocks in patients with and without AF were 12.9% and 3.5%, respectively (P = 0.0200). In multivariate stepwise Cox regression analyses controlling for baseline imbalances, demographic parameters, underlying heart disease, and therapy, history of AF independently predicted appropriate shocks (hazard ratio 2.7, P = 0.0278). Prolonged QRS duration (>130 ms) and QTc (>440 ms) modulated the effect of AF on appropriate shocks. Patients with both AF and QRS > 130 ms were more than five times more likely to receive an appropriate ICD shock (hazard ratio 5.4, P = 0.0396). Patients with AF and QTc > 440 ms experienced a greater than 12‐fold increased risk of appropriate shocks (hazard ratio 12.7, P = 0.0177).Conclusion: In prophylactic ICD recipients with left ventricular dysfunction, AF is associated with increased risk for ventricular tachyarrhythmias, particularly when combined with conduction and/or repolarization abnormalities.