Ventricular fibrillation in a patient with Wolff-Parkinson-White syndrome unrelated to pre-excited atrial fibrillation.

A 52-year-old man was admitted due to out-hospital cardiac arrest. Recurrent ventricular fibrillation (VF) occurred under therapeutic hypothermia thereafter. Previously inadverted full pre-excitation was documented exclusively and immediately prior to 4 out of the 5 VF relapses. Coronary vasospasm and early repolarization were also documented. An electrophysiological study demonstrated poor anterograde conduction over a left-sided accessory pathway. We theorize that maximum pre-excitation favored in-hospital VF by augmenting the repolarization vulnerability induced by therapeutic hypothermia, with coronary vasospasm accounting as the probable cause of out-hospital VF. A plausible VF mechanism in WPW syndrome unrelated to pre-excited atrial fibrillation is discussed.