Timolol for the treatment of frequent ventricular premature beats in patients without significant structural heart disease

The capability of timolol to suppress frequent ventricular premature beats in patients with normal and near-normal hearts was assessed in 12 patients in a double-blind, placebo-controlled, crossover design at dosages of 10, 20, and 30 mg/day. There was significant, although modest, suppression of ventricular premature beats at 10 and 20 mg/day (38% and 31% average decrease, respectively), but no effect (3% average decrease) at 30 mg/day. Six patients had > 70% reduction in frequency of ventricular premature beats at one or more dosage: four each at dosages of 10 and 20 mg/day and none at 30 mg/day. In contrast, beta-adrenoceptor-blocking effects, as measured by decreased heart rate, increased as the dosage of timolol was increased. There were few symptoms of adverse drug effects attributable to timolol. Timolol may be an effective treatment with minimum adverse effects in some patients with frequent ventricular premature beats.