Factors predisposing to ventricular proarrhythmia during antiarrhythmic drug therapy for atrial fibrillation in patients with structurally normal heart.

Background: Ventricular arrhythmia (VA) can occur during propafenone therapy in atrial fibrillation (AF) patients with structurally normal heart.

Objective: The purpose of this study was to evaluate the incidence and characteristics of propafenone-associated VAs in AF patients with structurally normal heart.

Methods: We studied and compared the risk of new-onset VAs between AF patients with structurally normal heart taking and those not taking propafenone in a nationwide longitudinal cohort in Taiwan (n = 127,197 since 2000). We then investigated the association between propafenone and VA in AF patients with structurally normal heart in a single-center database (n = 396).

Results: In the nationwide cohort, 102 patients (0.008% per patient-year) developed ventricular tachycardia (VT)/ventricular fibrillation (VF) during a follow-up period of 9.8 ± 3.5 years. After multivariate Cox regression analysis, propafenone treatment was a significant risk factor for new-onset VT/VF with a hazard ratio (HR) of 3.59 (95% confidence interval [CI] 1.30-9.89, P = .0136). Propafenone treatment offered protection against ischemic stroke with HR 0.649 (95% CI 0.55-0.77, P<.001). In the single-center study using ECG and medical records, the presence of inferior J wave, wider QRS, and old age were independent risk factors for VA after adjustment for clinical, biochemical, and echocardiographic variables.

Conclusion: Albeit with low incidence, propafenone therapy for AF was associated with new-onset VA in the nationwide longitudinal cohort study in Taiwan. Old age, presence of inferior lead J wave, and wider QRS on ECG were significant risk factors in our single-center study.