Cicloprolol is a beta-adrenoceptor antagonist patented by French pharmaceutical company Synthelabo S. A. for treatment of heart disorders. Cicloprolol has a weak beta-agonistic effect at normal levels of adrenergic discharge and acts as an antagonist at high levels of discharge. In clinical trials, Cicloprolol did not affect resting heart rate and blood pressure, but it reduced significantly peak exercise heart rate and peak rate-pressure product. The effect was especially significant in patients with sinus rhythm. The drug did not induce bradycardia or arrhyth- mias. Resting and exercise ejection rate were not affected. Cicloprolol improved the quality of life and the work capacity of 40% of patients with congestive failure due to ischemic etiology. Side effects were few and similar to placebo and cicloprolol.