Age-stratified comparison of prognosis in cardiac resynchronization therapy with or without prophylactic defibrillator for non-ischemic cardiomyopathy – a nationwide cohort study

Background and aims
Prior studies have suggested that the benefit from primary preventive defibrillator treatment for patients with non-ischemic cardiomyopathy primarily, treated with cardiac resynchronization therapy, may be age-dependent. We aimed to compare age-stratified mortality rates and mode of death in patients with non-ischemic cardiomyopathy who are treated with either primary preventive Cardiac Resynchronization Therapy-defibrillator (CRT-D) or CRT-pacemaker (CRT-P).

Methods
All patients with non-ischemic cardiomyopathy and CRT-P or primary preventive CRT-D who were implanted in Sweden during the period 2005-2020 were included. Propensity scoring was used to create a matched cohort. Primary outcome was all-cause mortality within five years.

Results
4027 patients were included, 2334 with CRT-P and 1693 with CRT-D. Crude 5-year mortality was 635 (27%) vs. 246 (15%), p 
Conclusion
In this nationwide registry-based study, patients with CRT-D have better five-year survival compared to patients with CRT-P. The interaction between age and mortality reduction not consistent, but patients with CRT-D aged