Defibrillator capability and all-cause mortality in patients receiving cardiac resynchronization therapy for non-ischemic cardiomyopathy: a Korean nationwide cohort study

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Concerns exist about the benefit of cardiac resynchronization therapy with a defibrillator (CRT-D) compared to those without a defibrillator (CRT-P), especially in patients with non-ischemic cardiomyopathy. We evaluated the association between defibrillator capability and all-cause mortality in patients receiving cardiac resynchronization therapy (CRT) for non-ischemic cardiomyopathy. METHODS: From patients with nationally registered cardiomyopathy in the Korea National Health Insurance Service (KNHIS) database, after the exclusion of those with ischemic heart disease, 1,478 patients with newly-implanted CRT-P (n=258) or CRT-D (n=1220) were identified from 2008 to 2020. The association between defibrillator capability and all-cause mortality was assessed with propensity score (PS) weighting to correct for differences between the groups. RESULTS: Compared with patients receiving CRT-D, those receiving CRT-P included more subjects older than 75. After PS weighting, over a mean follow-up period of 52.9 months (interquartile interval: 23.5-75.8), CRT-D was associated with a lower rate of mortality (6.5 vs 9.2 per 100 person-years) compared with CRT-P. The weighted risk of all-cause death in patients with CRT-D was lower than those with CRT-P within 1 year (hazard ratio [HR]: 0.70 [95% CI, 0.53–0.91]; p = 0.009) and 5 years (HR: 0.71 [95% CI, 0.61–0.83]; p < 0.001). Results were consistent regardless of subgroups, such as age, sex, year of registration, and comorbidities. CONCLUSIONS: In Korean patients with non-ischemic cardiomyopathy, the defibrillator capability of CRT was associated with reduced 1-year and 5-year all-cause mortality. This association was consistent across all the investigated subgroups. [Figure: see text]