Superficial accessory pathway in the Wolff-Parkinson-White syndrome--electrophysiological, surgical and histologic demonstration.

A superficial accessory pathway was demonstrated by electrophysiologic techniques and surgical histopathology in 30-year-old male with Wolff-Parkinson-White syndrome, severe mitral valve disease and medically uncontrollable arrhythmias. In this patient, electrode catheter studies in the cardiac catheterization laboratory revealed antegrade and retrograde function of an accessory pathway between the anterior right atrium and the right ventricle. During surgery, electrophysiologic mapping confirmed the anterior location of this pathway. Blunt dissection in the fat pad of the A-V groove between the right atrium and ventricle revealed the accessory pathway which consisted of tissue strands superficial to the A-V ring. These were removed and on histological examination were composed of ordinary myocardial cells. Concomitant replacement of the patient's calcified stenotic and regurgitant mitral valve was carried out. Postoperatively, there was complete regression of the preexcitation and arrhythmias.