Terminal ventricular arrhythmias in patients with CIEDs

Introduction

Cardiac implantable electronic devices (CIEDs) are widely used in contemporary clinical practice. These patients are regularly followed, and arrhythmias occurring during their lifetime are continuously recorded and assessed during routine device interrogations. However, limited data are available on arrhythmic events occurring immediately prior to death in this patient population.

Aim

To evaluate the incidence and characteristics of malignant ventricular arrhythmias occurring immediately before death in patients with CIEDs who died outside a healthcare facility.

Patients and Methods:

A total of 296 patients with CIEDs (94 with implantable cardioverter-defibrillators [ICDs] and 202 with pacemakers; mean age 75 ± 12 years; 72% male) who died outside a healthcare facility and underwent autopsy at forensic medicine departments were included in the analysis. Data were collected from eight departments of forensic medicine. For each patient, reports from emergency medical services and/or coroners, autopsy protocols, and device interrogations were evaluated.

Results

Malignant ventricular tachycardia was documented in 124 patients (42%). It occurred more frequently in patients with ICDs than in those with pacemakers (53% vs. 39%; p = 0.03). A malignant ventricular arrhythmia was considered the likely primary cause of death in 74% of patients and a secondary event (resulting from another acute cardiac or non-cardiac condition) in 23%. In 3%, the causal relationship could not be determined.

In the subgroup of ICD patients who experienced a malignant ventricular arrhythmia prior to death (n = 50), 50% converted to pulseless electrical activity or asystole, while in the remaining 50%, ICD therapy failed to achieve definitive arrhythmia termination.

Conclusion

Malignant ventricular arrhythmias occurred in up to half of all patients prior to death. Among those who experienced such arrhythmias, the arrhythmia was the likely primary cause of sudden death in a substantial proportion of individuals with CIEDs. In cases where ICD therapy failed to achieve definitive termination of the malignant ventricular arrhythmia, it can be assumed that these events predominantly occurred in patients with end-stage myocardial failure and profoundly reduced cardiac reserve, rather than as a consequence of device malfunction.