Treatment of Ventricular Extrasystoles and Tachyarrhythmias in Acute Myocardial Infarction

Abstract

Two developments at the beginning of this decade exerted a profound influence upon clinical management of acute myocardial infarction: the in troduction of closed-chest resuscitation with electric shock therapy for ven tricular fibrillation, and the availability of continuous monitoring of the electrocardiogram by means of the cathode-ray oscilloscope. As a result of this, the coronary care unit has become a standard facility for the treatment of myocardial infarction. I t should be recognized that the concept of thera peutic centers for patients with myocardial infarction encompasses a broad range of facilities available in such units (1). On the one end of the spectrum, one can place the comprehensive cardiology center, equipped to treat all as pects and complications of myocardial infarction, including the use of emer gency surgery and artificial pump-support. On the other end, is the small area in a hospital in which nurses can observe the patient's rhythm displayed upon the monitoring oscilloscope. The great majority of coronary care units ap proach the latter end of the spectrum-based primarily on the availability of electrocardiographic monitoring units. Thus, the role of such units is the identification, early recognition, treatment, and prevention of dangerous arrhythmias. The most common arrhythmias that are potentially life-threat ening are related to increased "irritability" of the ventricular myocardium. The purpose of this review is to examine the rationale for the therapy of ventricular arrhythmias in acute myocardial infarction-both the fundamen tal and practical considerations. INCIDENCE OF ARRHYTHMIASDuring the earlier era, when the diagnosis of arrhythmias was based on their occurrence during routine examination of the patient or during record ing of an electrocardiographic tracing, the incidence of arrhythmias was es timated to range between 9 and 27 percent, with an average of 18 percent

Antiarrhythmic Drugs: Electrophysiological Actions

“…We have discussed a number of drugs including those most widely used in the treatment of clinical arrhythmias (4,10,14,144). In addition, we reviewed the actions of several agents of particular interest to us.…”