Death caused by cervical spine trauma due to a car accident, secondary to ventricular arrhythmia recorded by an implantable cardioverter-defibrillator

The incidence rate of syncope is 0.62% person-years,¹ while that of implantable cardioverter-defibrillator (ICD) shock–associated syncope is 7%.² In a study by Trappe et al,² 6% of ICD-implanted patients had been involved in car accidents; however, none of these accidents were attributable to ICD therapy. In the AVID (Antiarrhythmics Versus Implantable Defibrillators) trial,³ 8% of patients with an ICD received a shock while driving, but therapy delivery did not lead to an accident in any of the cases. Current recommendations for patients with an ICD suggest up to 3 months of restriction from driving post implantation / appropriate therapy for nonprofessional drivers and a permanent restriction in the case of professional ones.^4,5

We present a case of a 77-year-old man previously treated for arterial hypertension, chronic coronary syndrome (2 angioplasties of the left anterior descending artery in 2016 and 2019), and persistent atrial fibrillation. He had an ejection fraction of 18% and was in New York Heart Association (NYHA) class II when a single-chamber ICD for primary prevention was implanted on February 2, 2016 (detection zones shown in Figure 1A). On March 12, 2018, he had 2 episodes of ventricular fibrillation (VF), both of which were successfully treated by the ICD. In March 2019, a planned angioplasty of the left anterior descending artery was performed. The patient had an ejection fraction of 27% during the postoperative follow-up, although his NYHA class had worsened to class III.

On December 29, 2020, the patient was involved in a fatal rear-end collision. According to the rear driver, the patient’s vehicle stopped abruptly on the road, causing the collision. Based on the autopsy, the cause of death was extensive cervical and thoracic spine trauma.

Artefacts generated by transportation of the corpse after the accident consumed most of the ICD memory space; therefore, intracardiac electrograms (IEGMs) were saved for only 3 out of 8 high ventricular rate episodes that occurred on the day of the accident (Figure 1B). According to the retrieved data, the patient initially experienced slow ventricular tachycardia (VT) with an average rate of 176 bpm (Figure 1C), which was recorded in the monitoring zone at 11:36 AM. After 4 minutes, the rhythm degenerated to VF, which probably caused the sudden loss of consciousness, leading to an abrupt halt of the vehicle. Later, at 11:51 AM, the ICD recorded 3 episodes of nonsustained and high-rate rhythm ranging from 286 to 330 bpm. The next available IEGM was recorded at 12:24 PM (Figure 1D) and exhibited low-voltage VF. It was initially recorded in the monitoring zone but was interpreted as VT after a few seconds (because some ventricular episodes were below the sensing threshold), prompting the delivery of therapy by the ICD.

After the ICD intervention, a recurrence of VT (Figure 1E) and subsequent adequate ICD shocks could be observed (during cardiopulmonary resuscitation). The last available IEGM was recorded at 12:32 PM and presented VT with a wider QRS complex with changing morphology (Figure 1F).

The most probable course of events was that the unconscious driver suffered a fatal spinal cord injury; however, the opposite sequence (postmortem spine trauma) cannot be completely ruled out.

Although patients implanted with an ICD may be allowed to drive, they must be aware of the possibility of losing consciousness at any time during driving, which may not only impact their health and quality of life but also have legal and health consequences for other road users. Therefore, it is paramount that this subset of patients are vigilant about any chest discomfort, breathing irregularities, or fatigue that happen when driving.