Ventricular Antiarrhythmic Effects of Beta‐Adrenergic Blocking Drugs: A Review of Mechanism and Clinical Studies

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Abstract
Beta‐adrenergic blocking drugs are now commonly used in patients with ventricular arrhythmias. This review examines the possible mechanisms of their ventricular antiarrhythmic effect. Actions on the myocardial cell, as well as actions on the central and autonomic nervous system, are reviewed. Many clinical studies have attempted to show the efficacy of beta blockers in controlling ventricular arrhythmia and decreasing the incidence of sudden death after acute myocardial infarction. Although some of these clinical trials tended to show an impact on sudden death, the size of these trials or their design problems do not allow firm conclusions to be made. The Beta Blocker Heart Attack Trial (BHAT) is a placebo‐controlled, double‐blind, randomized trial of propranolol currently under way in the United States. Important additions to the previous trials include the addition of drug levels to ensure beta‐blocking dosage, long‐term electrocardiographic monitoring, and a study population of 4200 patients followed for an average of three years. These important design features will be of value in addressing some of the unanswered questions presented in this review.