Acute and Chronic Effects of an Adrenergic Beta-Receptor Blocking Agent (Propranolol) in Treatment of Cardiac Arrhythmias

The effects of intravenous and oral administration of propranolol, an adrenergic beta-receptor blocking agent, have been studied in 29 patients with various cardiac arrhythmias. The ventricular responses in chronic or paroxysmal ectopic supraventricular arrhythmias were decreased at rest or during exercise. Sinus tachycardias were regularly slowed. Two supraventricular tachycardias and one ventricular tachycardia, all consistently precipitated by exogenous stimuli, were prevented. Six instances of digitalis-induced arrhythmias were responsive to treatment. Propranolol, especially when given orally, is of definite value in selected disturbances of cardiac rhythm. Reasonable caution should be exercised, however, because of the risk of precipitation of congestive heart failure or hypotension in patients with limited cardiac reserves.