Myocardial Infarction and Atrial Arrhythmias

In each of 11 necropsied patients with myocardial infarction and atrial arrhythmias, a coronary occlusion was found proximal to the origin of the sinus node artery and there was infarction of the sinus node. The multiple factors influencing the onset of atrial arrhythmias during acute myocardial infarction are discussed. Infarction of the sinus node is only one of these factors. Other important ones are ischemia of the AV node, vagal and vagomimetic reflexes, atrial distention, and circulating chronotropic substances. By combination of a knowledge of the anatomy and pathology of the human coronary arteries with the observation of atrial arrhythmias during acute myocardial infarction, an accurate diagnosis of the point of coronary occlusion can often be made.