Sotalol, a beta adrenergic antagonist that prolongs action potential duration and refractoriness, was administered to ten patients with chronic, symptomatic ventricular ectopic activity. Eight patients had ischaemic heart disease, one patient congestive cardiomyopathy, and one patient atypical chest pain and no structural abnormality. Twenty-four hour Holter ECG tapes were analyzed during a drug-free period, and after three and six months of continuous Sotalol therapy. Satisfactory control of ventricular premature contractions was initially achieved in nine patients. Longer follow-up confirmed maintenance of antiarrhythmic efficacy in five (50%) patients. Sotalol was especially effective in reducing high grade arrhythmias (couplets, "R on T" VPCs). That efficacy and the low frequency of side-effects make Sotalol an agent of notable value in suppressing ventricular arrhythmias, especially in patients who require antianginal therapy.