Very early PVC and risk of ventricular fibrillation

Patient

48-year-old man with history of inferior infarction; hospitalization following the occurrence of 2 episodes of traumatic syncope; recording of this tracing;

Trace

Sinus rhythm (positive P wave in leads I, II, V5, V6 and negative in aVR); narrow QRS with probable inferior infarction; very early ventricular extrasystoles since occurring in the initial ascending phase of the T wave; left delay pattern, superior axis, with very probable right ventricular origin given the delayed transition (in V5);

Trace

Telemetry monitoring and tracing recorded during a cardiovascular arrest necessitating an emergency electrical shock; ventricular extrasystole identical to the previous tracing causing a degeneration of the rhythm into ventricular fibrillation;

Exergue

There are two distinct types of initiation of ventricular fibrillation: 1) as on this tracing, inaugural ventricular fibrillation with abrupt onset on a more or less early ventricular extrasystole; 2) initial episode of ventricular tachycardia subsequently degenerating into ventricular fibrillation.