Subepicardial infarction, myocardial impression, and ventricular penetration by sutureless electrode and leads.

Postmortem examination two weeks following implantation of a demand pacemaker with sutureless electrodes demonstrated that (1) the loops of intrapericardial electrode leads indented the myocardium and produced a circumscribed area of subepicardial necrosis, and (2) one of the electrode coils protruded into the right ventricular cavity. The use of extrapericardial electrode leads and left ventricular implantation sites should avoid these problems.