Anti-arrythmia efficacy and effects on left ventricular function of flecainide have been evaluated in 9 patients with symptomatic non sustained ventricular tachycardia (NSVT) and left ventricular ejection fraction (LVEF) lower than 30%, respectively detected by Holter monitoring and radionuclide angiocardiography in basal conditions. Seven to eleven days after starting flecainide therapy (100 mg b.i.d.), Holter and radionuclide angiocardiography were repeated. In 56% of patients a ventricular premature beats (VPB) reduction more than 70% was obtained and total VPB suppression was achieved in 33% of patients. Total suppression of NSVT was obtained in 67% of patients; LVEF did not show significant changes. Thus, antiarrhythmic efficacy of flecainide resulted in agreement with the previous reports, whereas no patient developed signs or symptoms of heart failure or pro-arrhythmia.