Does long-term survival after ICD implantation differ according to the underlying cardiomyopathy etiology compared to the expected survival of the general population?
Long-term survival after ICD implantation varies significantly by underlying cardiomyopathy etiology, suggesting that risk stratification and patient selection should incorporate etiology rather than relying solely on LVEF.
BACKGROUND: Implantable cardioverter-defibrillators (ICDs) reduce sudden cardiac death in selected populations. However, their long-term prognosis may differ according to the underlying cardiomyopathy. We aimed to evaluate long-term survival after ICD implantation according to cardiomyopathy etiology and to contextualize outcomes relative to the expected survival of the general population. METHODS: This retrospective cohort included 1091 consecutive adults who underwent ICD implantation at the regional referral center in Asturias, Spain, between 2015 and 2024. Patients were classified as ischemic cardiomyopathy (ICM, n = 588), non-ischemic dilated cardiomyopathy (NI-DCM, n = 332), or other arrhythmogenic cardiac conditions (ACC, n = 171), including hypertrophic cardiomyopathy (HCM). Observed survival was estimated using Kaplan-Meier methods. Expected survival was derived from national life tables matched by age, sex, calendar year, and region. Relative survival and excess mortality were calculated using the Ederer II method at 4, 8, and 12 years. Multivariable Cox regression analysis was performed to adjust for major clinical confounders. RESULTS: The cohort was predominantly male (82.1%), with a mean age of 63.1 ± 13.1 years and mean LVEF of 37.9 ± 19.3%. ICD implantation was performed for primary prevention in 75.6% of patients. ICM was the most frequent substrate (53.9%), followed by NI-DCM (30.4%) and ACC (15.7%). ICM patients showed the poorest prognosis, with excess mortality compared with the general population. NI-DCM demonstrated intermediate outcomes, whereas ACC showed survival trajectories closely approximating expected population survival. CONCLUSIONS: Long-term survival after ICD implantation differed according to cardiomyopathy etiology. These findings support an etiology-informed approach to risk stratification, patient selection, and long-term management beyond a purely LVEF-based strategy.
Lorca et al. (Fri,) studied this question.