Persistent fetal dispersion of the atrioventricular node. Association with the Wolff-Parkinson-White syndrome.

Symptomatic supraventricular tachycardias developed in a 58-year-old man not long before he also was found to have metastatic cancer. During electrophysiological studies, type A Wolff-Parkinson-White syndrome was defined and at least four different forms of supraventricular tachycardias were documented. When he died of his cancer, autopsy studies included special examination of his heart and its conduction system. There was a slender connection between the left atrium and left ventricle posterior to the margo obtusus, composed of ordinary working myocardial cells. There was also persistent fetal dispersion of the atrioventricular (AV) node within the central fibrous body, forming a suitable anatomical substrate for reentrant tachycardias originating entirely there. The anatomical and electrophysiological findings are discussed relative to the question of surgery in such patients, since cutting the lateral AV connections might eliminate the delta wave but not the supraventricular tachycardias.