Acute and chronic effects of an adrenergic beta-receptor blocking agent (propranolol) in treatment of cardiac arrhythmias.

THE INTRODUCTION of the adrenergic beta-receptor blocking agent, pronethalol,1 and the more recent availability of its analogue propranolol2 have served as a new impetus in the pharmacological study of the cardiovascular system. Clinical use of these compounds has been explored in the treatment of hypertension,3 angina pectoris,4 prolonged systemic hypotension,5 hypertrophic subaortic stenosis,6 and pheochromocytoma.7 A fundamental effect of the beta-receptor blocking agents is their ability to slow the heart rate, and for this reason Black and Stephenson' suggested their use in certain cardiac arrhythmias. Stock and Dale8 found that pronethalol slowed the ventricular rate in patients with atrial fibrillation. This effect was particularly noticeable in the digitalized patient. Although pronethalol (Nethalide; Alderlin) proved to be carcinogenic in mice,9 its successor, propranolol (Inderal), has not been. Recent studies'0 11 have demonstrated the latter to be effective in decreasing the frequency of the ventricular response in patients with atrial fibrillation, atrial flutter, and ectopic atrial tachycardia when it was given intravenously. The present report further confirms the ability of propranolol to slow the ventricular rate in digitalized patients with supraventricular arrhythmias. Our experience with the chronic oral administration of propranolol