AN UNUSUAL SITE OF VENTRICULAR PACING OCCURRING DURING USE OF TRANSVENOUS CATHETER PACEMAKER

A patient is presented who maintained the electrocardiographic pattern of an intraventricular conduction defect similar to a RBBB for 18 months after an artificial pacemaker was thought to have been placed transvenously into her right ventricle. At autopsy, the electrodes were found to have traversed the coronary sinus and entered the middle cardiac vein. This resulted in pacing from the epicardial surface of the left ventricle. To our knowledge, this abnormal location of a pacemaker electrode has not previously been reported. Electrocardiographic evidence for malpositioning is presented. The possible significance of a persistent RBBB in patients being paced from the right ventricle is discussed. © 1969.