Postmortem interrogation of cardiac implantable electronic devices - results from a large prospective registry

Background Postmortem interrogation of cardiac implantable electronic devices (CIEDs) can provide valuable insights into device function, battery status, and terminal rhythm prior to death. Despite its clinical and forensic relevance, large-scale systematic analyses remain scarce, and postmortem CIED interrogation is still not routinely implemented in most centers. Aims This prospective registry aimed to assess the feasibility of postmortem CIED interrogation and investigate the incidence of CIED defects and arrhythmia-related causes and the time of death. Methods Between 2016 and 2025, all CIEDs explanted during medicolegal autopsy at the Institute of Legal Medicine, were interrogated in the Department of Electrophysiology and systematically analyzed regarding battery condition, functional integrity and Holter data. Results A total of 285 CIEDs were analyzed. The majority were pacemakers (dual chamber: n=138, 48%; single-chamber: n=64, 22%; CRT-P: n=3, 1.1%; leadless pacer: n= 3, 1%), followed by implantable cardiac defibrillators (ICDs; single-chamber: n=31, 11%; CRT-D: n=29, 10%; dual-chamber: n=10, 3.5%; subcutaneous ICD: n=1, 0.4%). Implantable loop recorders (ILRs) were interrogated in 6 (2%) cases. Patients were found dead at an average age of 77 (± 13) years and 93 (33%) were female. The median time from last device interrogation to death was 103 days [IQR 35–180]. At time of death, 273 devices (96%) showed normal battery status. In cases displaying ERI (n=10, 3.5%) or EOS (n=3, 1%) prior to death, battery depletion did not cause relevant device dysfunction in any case. Overall, 267 devices (94%) showed a normal device function during time of death, in 17 (6%) cases, signs of device malfunctions could be observed . In one case, premortem device integrity could not be determined. A device dysfunction possibly leading to death was found in 6 cases (2%). Holter data were retrievable in 261 devices (92%), showing premortem events in 171 cases (66%). In 50 cases (28%) a sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) was identified, timely related to patient death, while in 6 cases (3%), a bradycardic event was identified. Overall, in 61 cases (21%), postmortem interrogation enabled an estimation or determination of the time of death. Conclusion With 285 cases, this represents the largest systematically analyzed postmortem CIED registry worldwide. Postmortem device interrogation is generally feasible and Holter readouts are possible in most interrogations. Overall, CIED dysfunction is rare and even in cases showing ERI or EOS premortem, battery depletion did not cause meaningful device dysfunction. Interrogations can frequently provide meaningful insights into terminal rhythm and time of death. This highlights its clinical and forensic relevance and underscores the need to establish local structures to routinely perform postmortem CIED interrogations.