Relationship between heart rate and ventricular ectopic rhythm in acute myocardial infarction

Summary The study of 1313 time intervals from 146 patients with acute myocardial infarction showed that a linear relationship exists between the occurrence of ventricular ectopic beats or runs of ventricular ectopic beats and the heart rate. With faster heart rates, the percentage of these arrhythmias is decreased. Ventricular tachycardias and ventricular fibrillation or flutter were also seen most commonly in bradycardia, but there was a second maximum in frequencies exceeding 110/min. It is supposed that in cases with such tachycardial heart action severe heart failure and myocardial hypoxia are often present and that under these circumstances, only relatively few ventricular ectopic beats are necessary to trigger ventricular tachycardias or ventricular flutter/fibrillation.These results underscore in clinical practice that acceleration of heart frequency is a reliable measure to suppress ventricular ectopic rhythm. Electrostimulation of the right atrium is recommended for this purpose, although a stable position for the electrode catheter within the atrium may be difficult to achieve.