[Dynamics of cardiac rhythm disorders in patients with myocardial infarction studied by 24-hour ECG monitoring].

The results of repeated 24-hour ECG monitoring in 81 patients with documented transmural and macrofocal myocardial infarction are reported. The occurrence and pattern of heart rhythm disorders, including high-grade ventricular extrasystoles within the first day of the attack, were determined, as was the correlation between the infarction site and the occurrence of arrhythmia. The frequency and number of extrasystoles were the highest in recurrent myocardial infarction with developing left-ventricular insufficiency. High diagnostic value of 24-hour ECG monitoring, as compared to routine recordings, is demonstrated. The monitoring showed a significant drop in the frequency and number of extrasystoles by the end of the acute phase, including cases where no antiarrhythmic drugs were administered, and a significant rise in those in the subacute phase of myocardial infarction. It is suggested that the latter fact may be due to increased patient's physical activity in the course of convalescence, and myocardial autoimmune processes developing in the subacute phase.