Unearthing the Evidence: Post-Mortem Interrogation of Cardiac Implantable Electronic Devices

Background: The diagnostic yield of post-mortem interrogation of cardiac implantable electronic devices (CIEDs) including pacemakers, defibrillators and implantable loop recorders has not been well described.
Methods: We reviewed all post-mortem CIED interrogations performed by the Victorian Institute of Forensic Medicine between 2005-2020 for investigation of sudden or unexplained death.
Results: 260 patients (69.8% male, median age 73.2 years [IQR 63.2-82.3]) underwent post-mortem CIED interrogation (202 pacemakers, 56 defibrillators and 2 loop recorders). CIEDs were implanted for a median of 2.0 [IQR 0.75-5] years, with 19 devices requiring replacement (and 4 end of life). Post-mortem interrogation was successful in 256 (98.5%) cases. Potential CIED malfunction was identified in 20 (7.7%) cases: untreated ventricular arrhythmias (n=12), battery depletion (n=6), and lead failure (n=2). CIED interrogation directly informed cause of death in 130 (50.0%) cases, with fatal ventricular arrhythmias identified in 121 patients (46.5%). 71 (27.3%) patients had abnormalities recorded by their device in the 30 days preceding death: non-sustained ventricular tachycardia (n=26), rapid atrial fibrillation (n=17), longevity concerns (n=23), intrathoracic impedance alarms (n=3), lead issues (n=1) or therapy delivered (n=1). In 6 cases where the patient was found deceased after a prolonged time, CIED interrogation accurately determined time of death. In one case, CIED interrogation was the primary method of patient identification.
Conclusion: Post-mortem CIED interrogation frequently contributes important information regarding critical device malfunction, pre-mortem abnormalities, cause and time of death or patient identity. Device interrogation should be considered for select patients with CIEDs undergoing autopsy.