Key result
First ICD or CRT-D shock is linked to ~3 years of subsequent survival.
Why the study?
This study evaluated the impact of ICDs and CRT-Ds on extending patient life expectancy following defibrillation shock.
Do ICDs and CRT-Ds extend life expectancy after a first defibrillation shock in patients with implanted devices?
Cohort (n=23,853)
Yes
Do ICDs and CRT-Ds extend life expectancy after a first defibrillation shock in patients with implanted devices?
ICD and CRT-D therapies provide substantial life extension, averaging over 3 years following a first defibrillation shock.
Indicates substantial post-shock survival in large real-world ICD cohort; extends observational data but leaves open need for prospective validation.
Background Implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) have revolutionized the management of life-threatening ventricular arrhythmias, becoming a cornerstone in the prevention of sudden cardiac death. These implanted devices use advanced arrhythmia detection algorithms to continuously identify abnormal rhythms and restore normal sinus rhythm through high-energy shocks. Purpose This study evaluated the impact of ICDs and CRT-Ds on extending patient life expectancy. Methods Patients were implanted with a variety of ICDs and CRT-Ds (Ellipse, Fortify, Entrant, Gallant, Neutrino, Quadra Assura, Unify Assura, Fortify Assura). Patients were included only if they had experienced at least one defibrillation shock since implant and had more than one post-shock transmission. For each patient, implant date, first defibrillation shock, and last transmission were recorded. Results 23,853 US-based patients who were implanted with ICDs and CRT-Ds (26% single-chamber ICD, 42% dual-chamber ICD, 32% CRT-D) and were enrolled in Merlin.net all received at least one defibrillation therapy. The times from implant to the last recorded transmission averaged 2091±210 days and 1898±978 days for ICDs and CRT-Ds, respectively. The mean times from implant to first defibrillation shock were 836±100 days for ICDs and 761±805 days for CRT-Ds. Finally, the mean times from first shock to last transmission representing life extension for this patient cohort was 1255±110 days and 1137±844 days for ICDs and CRT-Ds, respectively. Conclusion This study highlights the life-extending impact of ICD/CRT-D therapy in patients implanted with these devices. The observed life prolongment underscores the effectiveness of ICDs/CRT-Ds in preventing sudden cardiac death through timely defibrillation. These findings reinforce the critical role of ICDs/CRT-Ds in reducing mortality and improving the long-term outcomes in these cardiac patients.
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Sathialingam et al. (2026) conducted a cohort in Life-threatening ventricular arrhythmias (n=23,853). ICDs and CRT-Ds was evaluated on Time from first shock to last transmission (life extension). ICD and CRT-D therapy in patients who received at least one shock demonstrated a mean time from first shock to last transmission of 1255±110 days and 1137±844 days, respectively.
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