Effect of oral L-type calcium channel blocker on repetitive paroxysmal atrial fibrillation: Spectral analysis of fibrillation waves in the Holter monitoring

Abstract

Aims: The electrical remodelling is considered to play a role in promoting arrhythmogenic substrate of atrial fibrillation (AF), and intracellular calcium overload may play a key role, especially in its early phase. The effect of oral verapamil on repetitive paroxysmal AF (PAF) was evaluated in clinical cases. Methods and results: Thirty-five patients with repetitive PAF (total PAF duration >2/24 h) were divided into two groups with and without verapamil administration (240 mg/day) and they were followed-up for 12 months. Before and after the follow-up period, 24 h Holter ECG was recorded. In each Holter recording, total PAF duration and the longest PAF duration was evaluated and spectral analysis was performed for fibrillation waves in PAF episodes to evaluate the fibrillatory frequency. Total PAF duration was prolonged by 45 ± 79 min in the control group (n = 18) whereas shortened by 25 ± 55 min in the verapamil group (n = 17, P = 0.005). The fibrillatory frequency was increased from 5.66 ± 1.05 to 6.73 ± 1.02 Hz in the control group and was unchanged in the verapamil group. There was inverse relationship between Δtotal PAF duration and Δfibrillatory frequency (P = 0.0002). Conclusion: Verapamil prevented the increase in fibrillatory frequency in PAF patients in relatively long-term observation. Verapamil might be effective for prevention of the electrophysiological change and increase in PAF episodes at least in specific type of PAF cases. © The European Society of Cardiology 2007. All rights reserved.