Anomalous Atrioventricular Excitation Pro- duced by Catheterization of the Normal

During the withdrawal of a catheter-electrode through the right ventricle of 2 normal subjects the electrogram displayed briefly a short P-R interval and an aberrant QRS. In the simultaneously recoidle(l standard lead, the phenomenon simulated what is seen in the Wolff-Parkinson-W~hite syndlrome. The findings are presented in support of the physiologic, rather than anatomic, expla-nation for anomalous atrioventricular excitation. SODI-PALLARES and his associates ' have reported on the nature of the intracardiac deflections when the standard electrocar-diographic leads displayed the characteristics first described by Wolff, Parkinson, and White.2 As part of the study they were able to produce records of a similar type in dogs. This was accomplished by tapping the upper portion of the interventricular septum with a probe which had been pushed through the free wall of the right ventricle. Following such manipulation there were, occasionally, runs of a rhythm characterized by a normal P wave, a short P-R interval, and an aberrant QRS with a slurred initial ventricular deflection (delta wave,3 anom-alous component') not unlike that seen in anomalous atrioventricular excitation * in man