Ventricular arrhythmias and electrophysiological consequences of myocardial ischemia and infarction

Abstract

In the past 10 yr, the pace of research into ischemic disorders of rhythms has quickened; there are now partial descriptions of the electrophysiological alterations of specialized conducting tissues and of working myocardium during the different phases of ectopic rhythm disorders. In addition, there are data relevant to atrioventricular (AV) conduction disorders due to ischemia of the specialized conducting system. The description which follows is the result mostly of observations made after coronary occlusion in dogs because in this brief, and necessarily selective, review we have chosen to emphasize studies which included direct assessment of the electrophysiological function of ischemic tissues. All recognize that the experimental model may differ from the clinical condition. For various reasons, including the presence of multiple lesions and more variable collateral blood flow, the clinical pathophysiology undoubtedly is more variable and complex than the experimental. Also, many studies have used anesthetized open chest animals in which the heart rate and level of sympathetic stimulation are high. There is a need to extend such observations to unanesthetized animals and to man.