Ventricular arrhythmias prior to discharge after acute myocardial infarction.

One hundred consecutive patients in sinus rhythm and without routinely prescribed antiarrhythmic therapy were investigated for ventricular ectopic beats (VEB) prior to discharge after an acute myocardial infarction. The registration was performed for three hours during the day, including light exercise, and three hours at night. The overall VEB frequency was 70%. 34% had uniform VEBs, 22% multiform VEB'S, ANd 11% paired VEB'S 2% HAD THE R-on-T phenomenon and 1% ventricular tachycardia (VT). Ventricular irritability was more common in patients discharged after reinfarction, an estimated large infarct, if they had shown VT or ventricular fibrillation in the acute phase or when treated with diuretics only because of heart failure. There was no lowering of the VEB incidence at night, 17 patients having had ventricular arrhythmias at night only. In 5 cases the VEB'S were of a higher degree during exercise than at rest.