Reduction of ventricular arrhythmias by atenolol.

The effects of atenolol on ventricular arrhythmias were evaluated in 25 men with significant ventricular ectopy. The patients received 2 weeks each of placebo, 50, 100, and 200 mg of oral atenolol. Efficacy was determined by weekly 24-hour Holter monitors. In 20 patients who completed the protocol, the frequency of total ventricular ectopic beats, ectopic couplets, and ventricular tachycardia was significantly decreased after treatment. The complexity of ventricular ectopy was also decreased as measured by the Lown grade and the proportion of hours in which multiform ectopic beats were present. A therapeutic response, defined as the minimum percentage reduction in ventricular arrhythmias to demonstrate an effect due to atenolol rather than spontaneous variation, was achieved in up to 70% of patients for total number of ectopic beats, 75% for ectopic couplets, and 73% for ventricular tachycardia beats. The results show that oral atenolol is an effective agent for the treatment for ventricular arrhythmias.