Disopyramide in the maintenance of sinus rhythm after electroconversion of atrial fibrillation. A placebo-controlled one-year follow-up study.

In this multicentre study, 90 patients who left hospital in sinus rhythm after electroconversion of atrial fibrillation were randomized to double-blind treatment with either disopyramide (n = 44) or placebo (n =46). The groups were comparable regarding age and sex distribution, duration of atrial fibrillation, heart volume and NYHA-classification. Life-table analysis was used to estimate the percentage of patients still in sinus rhythm and tolerating treatment at control visits after 1,3,6,9 and 12 months. After 1 month there was already a significant difference (P<0.01) between the two groups (disopyramide 70%, placebo 39%), a difference that was still remaining after 12 months (disopyramide 54%, placebo 30%). Twenty-four patients, all relapsing to atrial fibrillation before six months on placebo, were converted to sinus rhythm once again. They were then treated with disopyramide in an open manner and after 12 months 37% were still in sinus rhythm. From the results of this study, disopyramide seems to be a useful drug in maintaining sinus rhythm after electroconversion of atrial fibrillation.