Inadvertent transarterial pacemaker insertion: an unusual complication.

We describe an unusual complication of pacemaker treatment in a patient who died after a replacement operation. In a difficult situation in which a functioning pacemaker was highly desirable and in which most of the available veins had already been used, the pacemaker electrode was inserted, by mistake, through a small artery. This was not detected by fluoroscopy during surgery. The postoperative X-ray examination seemed to indicate that the electrode tip was located in the coronary sinus, but the subsequent autopsy revealed it to be located in the left ventricle.