Asymptomatic left ventricular malposition of a transvenous pacemaker lead through a sinus venosus defect: follow-up over 17 years.

The case of a woman with an asymptomatic transvenous left ventricular endocardial pacemaker lead is presented. The chest X ray and the electrocardiogram suggested pacemaker catheter malposition. By two-dimensional echocardiography, the pacemaker lead was shown to cross from the left atrium through the mitral valve and implant in the left ventricular endocardium. The underlying sinus venosus defect and the passage of the electrode through this interatrial communication were directly visualized by transesophageal echocardiography. No thrombotic material attached to the lead was detected corresponding to the patient's uneventful course for surprisingly more than 17 years without evidence of past or present neurological deficiencies or of peripheral embolic phenomena. Thus, no operative correction was performed. Warfarin sodium therapy, however, was initiated.