Autopsy findings with permanent pervenous pacemakers.

Abstract

Of 130 patients who received permanent pervenous pacemakers in the last 2 years at the Massachusetts General Hospital, 21 have died; complete postmortem data are available on seven who died 5 days to 18 months after insertion of the pacemaker. No deaths were related to pacemaker malfunction. No patient received routine anticoagulant therapy. The intracardiac portions of all pacemaker electrodes were 30 to 80% endothelialized. In three cases tiny, organized mural thrombi formed on these sheaths, but none appeared to give rise to pulmonary emboli. All pacemaker electrode tips were wedged firmly beneath the trabecular system of the right ventricular apex and elicited varying degrees of local fibrous tissue reaction. Further focal fibrotic attachments occurred in the right atrium and superior vena cava. Although in four cases the electrodes adhered to the chordae tendineae, the long-term presence of an electrode did not appear to compromise tricuspid valve function. Late removal of an electrode may be hazardous because of its firm attachments to the endocardium and tricuspid valve.