[Cardiac arrhythmias in the chronic phase of myocardial infarction (author's transl)].

Incidence and type of arrhythmia, using continuous ECG monitoring, were examined in 79 patients six weeks to 24 months after acute myocardial infarction, the findings being compared with arrhythmias at rest and on exercise, and correlated with signs of heart failure and coronary insufficiency. Arrhythmias were revealed in 16% (n = 13 at rest) and 19% (n = 10 of 52) on exercise. But continuous ECG monitoring revealed it in 86% (n = 68). On the other hand, arrhythmias may occur in the resting ECG but be rare on continuous monitoring. Ventricular extrasystoles were the most common arrhythmia, often multifocal and giving rise to bigeminy, only rarely as a result of exercise. Such extrasystoles usually showed right or right and left bundle conduction delays. Their frequency increased with increasing age of the patient. They were particularly frequent in patient who already had cardiac symptoms at rest, in patients with a large heart, and those who could not easily be exercised. Arrhythmias were more frequent a year after infarction than shortly before discharge from hospital or six months after infarction.