[Electrocardiography of delayed potentials in post-excitation syndrome].

Electrophysiological investigation and pericardial mapping have succeeded in isolating a particular type of ventricular tachycardia occurring in young subjects with no coronary artery disease who have dysplasia of the right ventricle. When these patients are no longer controlled by medical treatment, they may benefit from surgery. This condition is characterised by the presence of delayed potentials which appear after the end of ventricular depolarisation as recorded by épicardial mapping. This post-excitation phenomenom may also be demonstrated either by an intracavitary electrode or sometimes on an amplified ECG. This study describes a new method using the techniques of signal averaging and summation technique to demonstrate the delayed potential in the post-excitation syndrome. It is non-invasive, and seems to give better results than those obtained from intracavitary exploration.