Clinical Inferences of Cardiovascular Implantable Electronic Device Analysis at Autopsy

Background Cardiovascular implantable electronic device (CIED) removal and interrogation are recommended at autopsy in suspected cases of sudden cardiac death, but data on the role of nonselective post-mortem CIED (pacemaker or defibrillator) analysis in this setting are lacking. Objectives This study undertook an institutional registry analysis to determine the utility of systematic routine CIED removal, interrogation, and analysis at autopsy. Methods From May 19, 2009, to May 18, 2015, autopsy subjects with a CIED at a Johns Hopkins University medical institution (Baltimore, Maryland) underwent CIED removal and interrogation by an electrophysiologist for clinical alerts. The CIED was then submitted for technical analysis by the manufacturer. The CIED interrogation, the manufacturer's technical analysis, and the final autopsy report were all cataloged in the Johns Hopkins Post-mortem CIED Registry. Results A total of 2,025 autopsies were performed; 84 subjects had CIEDs removed and analyzed. These devices included 37 pacemakers and 47 defibrillators. Overall, 43 subjects had died suddenly, and 41 had not died suddenly. Significant clinical alerts (sustained tachyarrhythmias or an elevated fluid index value) were seen in 62.8% cases of sudden deaths. In the nonsudden death cohort, 19.5% displayed a significant clinical alert. Significant association of CIED alerts were noted when comparing sudden deaths versus nonsudden deaths (p < 0.001), defibrillators versus pacemakers (p < 0.005), and cardiac versus noncardiac causes of death (p < 0.001). Manufacturer analyses revealed a case of premature pacemaker battery depletion, as well as a hard reset in a defibrillator as a result of cold exposure. Conclusions Post-mortem CIED analysis was clinically useful in assisting with determination of the timing, mechanism, and cause of death in the majority of sudden deaths and in almost 20% of nonsudden deaths. The authors advocate CIED removal with analysis as an important diagnostic tool in all autopsies and to assist manufacturers in identifying potentially fatal device failures.