Cardiac Device Interrogation After Death 'Richly Informative'

Megan Brooks

December 29, 2021

Interrogating the cardiac implantable electronic device (CIED) after death can yield important information about critical device malfunction, premortem abnormalities, and the mechanism and timing of death, a new study suggests.

Postmortem CIED interrogation is "richly informative" in assisting both cardiac and forensic investigations and "should be considered for select patients with CIEDs undergoing autopsy," say Elizabeth Paratz, MBBS, Department of Cardiology, Baker Heart and Diabetes Institute, Prahran, Victoria, Australia and colleagues.

Their study results were published online December 22 in JACC: Clinical Electrophysiology

Cause of Death Revealed in Half of Cases

They reviewed CIED interrogations in 260 deceased individuals undergoing medicolegal investigation of sudden death (162 patients) or unexplained death (98 patients) by the Victorian Institute of Forensic Medicine between 2005 and 2020.

Roughly two thirds were male (68.8%) and their median age was 72.8 years; 202 patients had pacemakers, 56 had defibrillators, and 2 had loop recorders. The cause of death was cardiac in 79.6% of cases.

Postmortem CIED interrogation was successful in 98.5% cases and directly informed cause of death in 131 cases (50.4%), with fatal ventricular arrhythmias identified in 121 patients.

CIED interrogation assisted in determining the cause of death in 63.6% of cases of sudden death and 28.6% of nonsudden death cases.

In 20 cases (7.7%), CIED interrogation uncovered potential device malfunction. Issues included failure to appropriately treat ventricular arrhythmias in 13 cases, lead issues in 3 cases including 2 cases resulting in failure to treat ventricular arrhythmias, as well as battery depletion in 6 cases.

In 72 patients (27.7%), the device recorded abnormalities in the 30 days before their death. These abnormalities included nonsustained ventricular tachycardia in 26 cases, rapid atrial fibrillation in 17, elective replacement indicator or end-of-life status in 22, intrathoracic impedance alarms or lead issues in 3 each and therapy delivered in 1 instance.

"In several cases, the absence of an arrhythmia carried medicolegal implications: for example, in 8 fatal motor vehicle accident cases, only 1 patient had a ventricular arrhythmia documented on their CIED," Paratz and colleagues report.

And in 6 cases in which the patient was found dead after a prolonged period, CIED interrogation determined time of death. And in one case, CIED interrogation was the primary means of identifying the patient.

Still, postmortem CIED interrogation remains uncommon, the study team notes.

They point to a 2007 survey of Chicago morticians that found roughly 370 CIEDs were explanted per year prior to cremation, but only 4% of morticians had ever returned a CIED to the manufacturer for analysis.

"Encouraging postmortem interrogation of CIEDs may assist in postmarketing surveillance for critical faults, as well as in providing an electrophysiological appraisal of terminal rhythms and device responses in a variety of physiological scenarios," the researchers say.

The study had no commercial funding. Paratz is supported by a National Health and Medical Research Council (NHMRC) / National Heart Foundation (NHF) co-funded Postgraduate Scholarship, Royal Australasian College of Physicians JJ Billings Scholarship, and PSA Insurance Cardiovascular Scholarship. The authors have disclosed no relevant financial relationships.

JACC: Clinical Electrophysiology. Published online December 22, 2021. Abstract

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