Rise in ICD Shock Impedance: Lead Fracture or Death?

Connected to the cloud at time of death: a case report

BACKGROUND

Our case report provides the first clinical evaluation of autopsy practices for a patient death that occurs on the cloud. We question how autopsy practices may require adaptation for a death that presents via the 'Internet of Things', examining how existing guidelines capture data related to death which is no longer confined to the patient's body.

CASE PRESENTATION

The patient was a British man in his 50s, who came to the attention of the medical team via an alert on the cloud-based platform that monitored his implanted cardioverter defibrillator (ICD). The patient had a background of congenital heart disease, with previous ventricular fibrillation cardiac arrest, for which the ICD had been implanted two years earlier. Retrospective analysis of the cloud data demonstrated a gradually decreasing nocturnal heart rate over the previous three months, falling to a final transmission of 24 beats per minute (bpm). In the patient post-mortem the ICD was treated as medical waste, structural tissue changes precluded the effective evaluation of device hardware, potential issues related to device software were not investigated and the cause of death was assigned to underlying heart failure. The documentation from the attending law enforcement officials did not consider possible digital causes of harm and relevant technology was not collected from the scene of death.

CONCLUSION

Through this patient case we explore novel challenges associated with digital deaths including; (1) device hardware issues (difficult extraction processes, impact of pathological tissue changes), (2) software and data limitations (impact of negative body temperatures and mortuary radio-imaging on devices, lack of retrospective cloud data analysis), (3) guideline limitations (missing digital components in autopsy instruction and death certification), and (4) changes to clinical management (emotional impact of communicating deaths occurring over the internet to members of family). We consider the implications of our findings for public health services, the security and intelligence community, and patients and their families. In sharing this report we seek to raise awareness of digital medical cases, to draw attention to how the nature of dying is changing through technology, and to motivate the development of digitally appropriate clinical practice.

Forensic perspectives on postmortem CIED interrogation: A systematic review and meta-analysis

BACKGROUND

Cardiac implantable electronic devices (CIED) are a heterogeneous group of medical devices with increasingly sophisticated diagnostic capabilities, which could be exploited in forensic investigations. However, current guidelines are lacking clear recommendations on the topic. The first aim of this systematic review is to provide an updated assessment of the role of postmortem CIED interrogation, and to give practical recommendations, which can be used in daily practice. Secondly, the authors aim to determine the rates of postmortem CIED interrogation and autopsy investigations, the type of final rhythm detected close to death (with a focus on the significance of documented arrhythmias), as well as the role of postmortem CIED interrogation in the determination of final cause/time of death, and any potentially fatal device malfunctions.

METHODS

A systematic search in MEDLINE and Scopus aiming to identify reports concerning postmortem human CIED interrogation was performed, including a systematic screening of reference lists. Case reports, letters to the editors, commentaries, review articles or guidelines were excluded, along with studies related to cardiac devices other than CIED. All data were pooled and analyzed using fixed-effects meta-analysis models, and the I2 statistic was used to assess heterogeneity.

RESULTS

A total of 25 articles were included in the systematic review, enrolling 3194 decedent CIED carriers. Ten studies (40%) had a 100% autopsy rate, whereas in further 6 studies autopsy findings were variably reported; CIED interrogation was available from 22 studies (88%), and it was never performed prior to autopsy. The overall rate of successful postmortem CIED interrogation was 89%, with high heterogeneity among studies, mainly due to device deactivation/battery discharge. Twenty-four percent of CIED carriers experienced sudden cardiac death (SCD), whereas non-sudden cardiac and non-cardiac death (NSCD, NCD) were reported in 37% and 30% of decedents, respectively. Ventricular tachyarrhythmias were recorded in 34% of overall successfully interrogated CIED, and in 62% of decedents who experienced a SCD; of all ventricular tachyarrhythmias recorded, 40% was found in NSCD or NCD. A clear interpretation of the etiological role of recorded arrhythmias in the causation of death required integration with autopsy findings. Overall, potentially fatal device malfunctions were detected in 12% of cases.

CONCLUSIONS

Postmortem CIED interrogation is a valuable tool for the determination of the cause of death, and may complement autopsy. Forensic pathologists need to know the potential utility, pitfalls, and limitations of this diagnostic examination to make this tool as much reliable as possible.

Detecting deceased patients on cardiac device remote monitoring: A case series and management guide for cardiac device services

BACKGROUND

Remote monitoring (RM) of implantable cardiac devices provides substantial and complex information, presenting new challenges such as detection of a patient's death.

OBJECTIVE

This study aims to describe RM transmissions indicating death and propose a management strategy for services.

METHODS

The study included consecutive ambulatory outpatients whose deaths were detected via RM. Clinical and device data were collected from electronic records, and ethical approval was obtained from the service's institutional review board.

RESULTS

Over a 9-year period (2014-2023), 28 patients were detected. The deceased patients had implantable cardioverter-defibrillators, pacemakers, and implantable loop recorders. In 54% of the cases, the patient's death had already been recognized. Alert transmissions indicating death were commonly related to ventricular arrhythmia events, but also due to lead measurements, and implantable loop recorder battery status. Several diagnostic features may indicate a patient's death. The most reliable was the presenting electrogram, demonstrating base rate pacing with no capture. Device diagnostics, lead parameters, and arrhythmia recordings may indicate death; however, not all cases present with recordings and diagnosis may not be conclusive. A majority (82%) had ventricular arrhythmia at the time of death. In cases where defibrillator shocks were delivered, the arrhythmia reinitiated shortly after successful cardioversion. Delayed therapy was observed, and some patients did not receive defibrillator shocks because of discriminators or because the arrhythmia rate fell below the shock zone.

CONCLUSION

Detecting a patient death via RM presents unique challenges and considerations for services. Standard operational policies and legal consultation should be established to address the implications.

A case report of an unusual cause of increased impedance after generator exchange

Background

Remote monitoring has emerged as a complement to in-person care for patient with cardiac implantable electronic devices (CIEDs). It provides the care team with information about device integrity, programming issues, or other medical data (i.e. arrhythmias) and since 2015 has been recognized as a part of standard management by the Heart and Rhythm Society for all patients with CIEDs. However, while it can provide invaluable information to providers, the volume of generated data can increase the risk of oversight. We present a novel case of apparent device malfunction that on closer scrutiny was obvious, but provides a lesson in the mechanisms by which data can be artifactual.

Case summary

A 62-year-old male presented after his cardiac resynchronization therapy-defibrillator (CRT-D) alerted him that his device was at an elective replacement interval (ERI). He underwent an uncomplicated generator exchange; however, 2 weeks later, a remote alert showed that his device was at ERI and all impedances were above the upper limit. Device interrogation the following day demonstrated that the new device was functioning appropriately and his home monitor had in fact paired with his old generator. He obtained a new home monitor, and subsequent remote transmissions have demonstrated that his device is functioning appropriately.

Discussion

This case demonstrates the importance of careful review of details from home-monitoring data. While concerning for device malfunction, there could be alternative causes when alerts are generated by remote monitoring. To our knowledge, this is the first report of this mechanism of alert via a home-monitoring device and should be considered when reviewing unusual remote download data.

Determination of time of death by blinded post-mortem interrogation of cardiac implantable electrical devices

Postmortal interrogation of cardiac implantable electrical devices (CIED) may contribute to the determination of time of death in forensic medicine. Recent studies aimed to improve estimation of time of death by combining findings from autopsy, CIED interrogation and patients´ medical history. CIED from deceased undergoing forensic autopsy were included, if time of death remained unclear after forensic assessment. CIED explanted from deceased with known time of death were analysed as a control cohort. CIED were sent to our device interrogation lab and underwent analysis blinded for autopsy findings, medical history and police reports. The accuracy of time of death determination and the accuracy of time of death in the control cohort served as primary outcome. A total of 87 CIED were analysed. The determination of time of death was possible in 54 CIED (62%, CI 52–72%). The accuracy of the estimated time of death was 92.3% in the control cohort. Certain CIED type and manufacturers were associated with more successful determination. Blinded postmortal analysis enables a valid determination of the time of death in the majority of CIED. Analysis of explanted CIED in a cardiological core lab is feasible and should be implemented in forensic medicine.

Postmortem Interrogation of Cardiac Implantable Electronic Devices: A 15-Year Experience

OBJECTIVES

This study sought to define the feasibility and utility of postmortem cardiac implantable electronic device (CIED) interrogation.

BACKGROUND

The diagnostic yield of routine postmortem interrogation of CIEDs including pacemakers, defibrillators, and implantable loop recorders has not been established.

METHODS

The study reviewed all CIED interrogations in deceased individuals undergoing medicolegal investigation of sudden or unexplained death by the Victorian Institute of Forensic Medicine between 2005 and 2020.

RESULTS

A total of 260 patients (68.8% male, median age 72.8 years [interquartile range: 62.7-82.2 years]) underwent CIED interrogation (202 pacemakers, 56 defibrillators, and 2 loop recorders) for investigation of sudden (n = 162) or unexplained (n = 98) death. CIEDs were implanted for median of 2.0 years (interquartile range: 0.7-5.0 years), with 19 devices at elective replacement indicator and 5 at end of life. Interrogation was successful in 256 (98.5%) cases. Potential CIED malfunction was identified in 20 (7.7%) cases, including untreated ventricular arrhythmias (n = 13) and lead failures (n = 3, 2 resulting in untreated ventricular arrhythmia). Interrogation directly informed cause of death in 131 (50.4%) cases. A total of 72 (27.7%) patients had abnormalities recorded in 30 days preceding death: nonsustained ventricular tachycardia (n = 26), rapid atrial fibrillation (n = 17), elective replacement indicator or end-of-life status (n = 22), intrathoracic impedance alarms (n = 3), lead issues (n = 3), or therapy delivered (n = 1). In 6 cases in which the patient was found deceased after a prolonged period, interrogation determined time of death. In 1 case, CIED interrogation was the primary means of patient identification.

CONCLUSIONS

Postmortem CIED interrogation frequently contributes important information regarding critical device malfunction, premortem abnormalities, mechanism, and time of death or patient identity. Device interrogation should be considered for select patients with CIEDs undergoing autopsy.

Postmortem ICD interrogation in mode of death classification

BACKGROUND

The definition of sudden death due to arrhythmia relies on the time interval between onset of symptoms and death. However, not all sudden deaths are due to arrhythmia. In patients with an implantable cardioverter defibrillator (ICD), postmortem device interrogation may help better distinguish the mode of death compared to a time-based definition alone.

OBJECTIVE

This study aims to assess the proportion of "sudden" cardiac deaths in patients with an ICD that have confirmed arrhythmia.

METHODS

We conducted a literature search for studies using postmortem ICD interrogation and a time-based classification of the mode of death. A modified QUADAS-2 checklist was used to assess risk of bias in individual studies. Outcome data were pooled where sufficient data were available.

RESULTS

Our search identified 22 studies undertaken between 1982 and 2015 with 23,600 participants. The pooled results (excluding studies with high risk of bias) suggest that ventricular arrhythmias are present at the time of death in 76% of "sudden" deaths (95% confidence interval [CI] 67-85; range 42-88).

CONCLUSION

Postmortem ICD interrogation identifies 24% of "sudden" deaths to be nonarrhythmic. Postmortem device interrogation should be considered in all cases of unexplained sudden cardiac death.