Repetitive ventricular ectopic activity in chronic ischaemic heart disease.

The characteristics of repetitive ventricular ectopic activity in 175 ambulatory patients after myocardial infarction are analysed. A total of 1 500 magnetic tape recordings were made on these patients over a period of up to 8 years. In the group of patients exhibiting few ectopic beats, i.e. less than 8/h, the incidence of ventricular salvoes and tachycardia was 9% and 4% respectively, whereas in the group exhibiting many ectopic beats, i.e. greater than or equal to 8/h, the incidence of ventricular salvoes and tachycardia was 60% and 30% respectively. Even though only 1 patient in the first group, exhibiting repetitive ventricular ectopic activity, died, in contrast to 10 in the second group, this is not of statistical significance. The coupling intervals between preceding normal sinus beats and beats which led to repetitive ventricular discharge were clustered between the shortest and the longest coupling intervals which did not lead to salvoes and tachycardia.