Treatment of atrial tachyarrhythmias and preexcitation syndrome with flecainide acetate

Abstract Sixteen consecutive patients who had ventricular preexcitation complicated by atrial fibrillation or flutter were treated with intravenous flecainide acetate after treatment with as many as 5 unsuccessful trial regimens with other drugs. In 15 patients who had atrial fibrillation, the shortest RR interval during spontaneous episodes was 210 ± 39 ms (mean ± standard deviation), and the average ventricular rate was 208 ± 37 beats/min. Intravenous flecainide prevented induction of atrial fibrillation in 4 of 9 patients and eliminated anterograde accessory pathway conduction in 9 of the 16 patients. In 5 patients whose atrial fibrillation remained inducible and who continued to have preexcitation, the shortest preexcited RR interval increased from 185 ± 29 to 281 ± 46 ms (p Fourteen patients who had favorable responses to intravenous flecainide were given an oral regimen of the drug. Oral treatment was discontinued early because of proarrhythmic effects in 2 patients, and after 2 1 2 months because of headaches in 1 patient. Eleven patients, 5 receiving concomitant β-blockade therapy, have continued to receive a regimen of flecainide for a mean of 21 months (range 3 to 48). Seven patients have had no clinical recurrence of arrhythmias. Recurrences in 4 patients have been rare and brief with no changes in therapy required.