The clinical significance of bradycardic rhythms in acute myocardial infarction

The clinical significance of bradycardic rhythms as they pertain to patients developing acute myocardial infarctions is reviewed. Proper therapy of the arrhythmia frequently is predicated on an understanding of (1) the pathophysiologic mechanisms responsible for the production of the bradyarrhythmia, (2) the hemodynamic and electrophysiologic consequences of the slow ventricular rate, and (3) the exact electrocardiographic interpretation of the bradycardic rhythm. These three points are discussed in detail and illustrated by appropriate electrocardiographic examples. The factors responsible for the production of the bradycardic rhythm as well as the consequences of the slow heart rate may be unique in a patient with an acute myocardial infarction. The advent of artificial pacing has made it mandatory to be able to predict initially which bradyarrhythmia is likely to be progressive—in terms of further, more severe disturbance in impulse formation or conduction, or hemodynamic or electrophysiologic consequences—and may not respond to a medical approach. Artificial pacing must be instituted early in patients with these disturbances.