Suppression of complex ventricular arrhythmias by oral flecainide.

The effectiveness and safety of oral flecainide for suppression of complex ventricular arrhythmias was tested in nine patients in a short-term (4 wk), single-blind, placebo-controlled experiment. The prevalence of multiform premature ventricular complexes (PVCs), couplets and nonsustained ventricular tachycardia (VT) (less than 3 PVCs at rate less than 100/min) was determined by 48-hr Holter monitoring on placebo and flecainide (200 to 300 mg b.i.d.) therapy. Multiform PVCs/hr were reduced by 96% in eight of nine patients (P less than 0.001). Couplets per 24-hr period were suppressed entirely in six patients (P less than 0.001). Couplets per 24-hr period were suppressed entirely in six patients (P less than 0.001) and reduced by 92% in the remaining two patients. VT runs per 24 hr were abolished in six patients (P less than 0.02) and reduced by 91% in one. As a group the frequency of PVCs per hour, couplets per 24 hr and VT per 24 hr was reduced by 96% (P less than 0.01) over than in the preceding placebo period. Flecainide (P less than 0.02) slowed heart rate by 10% and prolonged PR, QRS, and QTc intervals by 31%, 47% and 6%. No hematologic, hepatic, or renal abnormalities were found. Side effects were mild, transient, and central nervous system related; blurring of vision was the most frequent effect and was reported in four patients.