[Right ventricular intracardial recordings of late potentials in patients with acute myocardial infarction and recurrent ventricular tachycardias].

The role of delayed potentials in ventricular arrhythmias occurring in connection with acute myocardial infarction has been of increasing interest in recent years. In order to obtain further information about delayed electrical activity, we studied a group of 51 patients in the acute phase of myocardial infarction, and intracardiac recordings were made using bipolar electrodes. In 31 of the 51 patients we recorded delayed potentials 150-200 ms after the beginning of QRS. 14 patients showed delayed electrical activity in diastole even after the T wave. The same potentials as those obtained by intracardiac recording techniques were also recorded from the body surface using a signal-averaging technique. In several cases we were able to show that these delayed potentials initiated premature ventricular beats. In 1 patient a sustained ventricular tachycardia induced by delayed potentials was recorded. We found that delayed potentials could be abolished by antiarrhythmic drugs. There thus appears to be an important relationship between delayed electrical activity and the occurrence of ventricular arrhythmias.