Effects of Beta-Adrenergic Blockade with Propranolol in Patients with Atrial Arrhythmias

Abstract
IN patients with atrial arrhythmias the ventricular rate is primarily determined by the frequency of atrial-impulse generation and the functional refractory period of the atrioventricular node. It is well known that the sympathetic nervous system has an important role in regulating both the frequency of cardiac-impulse generation and the functional refractory period of atrioventricular conduction.1 2 3 Both stimulation of the cardiac sympathetic nerves and exogenous administration of catechol amines increase the ventricular rate in animals and in patients.1 2 3 4 5 6 This response is thought to be due to stimulation of beta-adrenergic neuroreceptors in the system of classification proposed by Ahlquist.7 Several new blocking . . .