A CASE OF WPW SYNDROME ASSOCIATED WITH MITRAL STENOSIS AND REFRACTORY ATRIAL FIBRILLATION

A 60 year-old man with Wolff-Parkinson-White (WPW) syndrome was admitted to our hospital because of atrial fibrillation and heart failure. He had a history of paroxysmal atrial fibrillation which had increased in frequency as mitral stenosis progressed over a period of 10 years. Since heart rate-dependent torsades de pointes appeared after DC defibrillation due to class IA antiarrhythmic agents, the drug was withdrawn and an intravenous infusion of isoproterenol was started. Sinus rhythm was restored and maintained by restarting the administration of the class I A antiarrhythmic agent. Electrophysiological examination revealed a single accessory conduction pathway and no retrograde conduction, the effective refractory period was prolonged to 330 msec. After the heart failure had improved, mitral valve replacement and transection of the bundle of Kent were performed. Because of the possibility of grave hemodynamic derangement induced by marked tachycardia, surgical treatment should be seriously considered in patients with mitral stenosis when associated with WPW syndrome and atrial fibrillation, even in those not classified as high risk patients.