Flecainide acetate was administered at a dose of 100 mg twice daily to 15 patients with drug-resistant ventricular ectopy. Eleven patients had evidence of organic heart disease. Left ventricular function was normal in 13 patients, and 2 patients had mild and moderate left ventricular dysfunction respectively. All patients underwent a control (off drugs) and a flecainide Holter ECG. Flecainide suppressed ventricular ectopy by greater than 70% in 13 patients (86.6%), suppressed bigeminal beats by greater than 90% in 13 (86.6%), suppressed ventricular couplets by greater than 90% in 12 of 14 patients (85.7%), and completely suppressed runs of nonsustained ventricular tachycardia in 6 of 9 patients (66.6%). In only one patient who showed a 69% suppression of ventricular ectopy did ventricular couplets increase. No side effects of the drug were noted. We conclude that flecainide at a dose of 100 mg twice daily is highly effective in suppressing ventricular ectopy that is resistant to other anti-arrhythmic agents.