Ventricular fibrillation in Wolff-Parkinson-White syndrome, type A.

A young individual who developed ventricular fibrillation following atrial fibrillation in the WPW syndrome is presented. The precise cardiac rhythm diagnosis is extremely important for proper management. When the QRS morphology is bizarre and the ventricular rate is very fast (200 to 300 b.p.m.) in atrial fibrillation, the WPW syndrome should be considered as the underlying disorder. Digitalis should be avoided in this circumstance because anomalous conduction may be accelerated by the drug, leading to deterioration of the clinical picture and even death. When an antiarrhythmic drug is to be used, intravenous lidocaine is the drug of choice. For the prophylactic measure, oral quinidine or procainamide is equally effective for atrial fibrillation with anomalous conduction in the WPW syndrome.