Effects of angiotensin receptor blockade on serial P-wave signal-averaged electrocardiograms after electrical cardioversion of persistent atrial fibrillation

AIMS: To evaluate the effects of the angiotensin II type 1 receptor blocker candesartan on P-wave signal-averaged electrocardiogram (P-SAECG) after electrical cardioversion in patients with atrial fibrillation (AF). METHODS AND RESULTS: One hundred and seventy-one patients with persistent AF were randomized to receive candesartan 8 mg/day or placebo for 3-6 weeks before and candesartan 16 mg/day or placebo for 6 months after electrical cardioversion. P-SAECG was recorded in 114 patients (57 in each treatment group) after cardioversion and repeated in those with sinus rhythm at 1 and 6 weeks, and 3 and 6 months. Filtered P-wave duration (FPD), root-mean-squared (RMS) voltages of the terminal 40 ms of the filtered P-wave, RMS voltage of the entire filtered P-wave, and the integral of the voltages in the entire PD were analysed. No effects of candesartan were observed on any P-SAECG parameter at baseline. In the subgroup of patients in sinus rhythm after 6 months, FPD was significantly shorter both at baseline (151 +/- 16 vs. 163 +/- 16 ms) and at 6 months (143 +/- 12 vs. 153 +/- 15 ms) in the candesartan (n = 15) compared with the placebo group (n = 21). CONCLUSION: Treatment with candesartan was associated with a shorter FPD in patients remaining in sinus rhythm for 6 months.