Abstract 4361551: Long term survival of older patients who receive cardiac resynchronization therapy devices with or without defibrillation therapy

Background: Cardiac resynchronization therapy (CRT) is an established treatment for heart failure (HF) patients that can be delivered either through a pacemaker (CRT-P) or a defibrillator (CRT-D). Despite significant differences between these two devices, current published guidelines do not separate recommendations for CRT-P versus CRT-D. We had conducted a pilot randomized controlled trial (RCT) of CRT-P versus CRT-D in eligible HF patients (age ≥75 years) and we here report their long-term mortality outcomes. Methods: Older HF patients (age=81±5 years, 27% women, LVEF=25±6%) indicated for CRT who had no prior history of ventricular arrhythmias were included. Patients who agreed to participate in the study but declined randomization received their device of choice and enrolled in an observational registry (OR) (Figure 1). All patients were followed to the primary endpoint of death from any cause, through May 1 st , 2025. Results: A total of 88 patients (36 RCT and 52 OR) were followed for a median of 3.4 years, during which time 49 (56%) patients died. There were no differences in overall survival between CRT-P and CRT-D recipients (adjusted hazard ratio (HR) 0.96, p=0.89, Figure 2). A majority (68%) of patients who refused randomization chose a CRT-D device. Patients who were enrolled in the RCT had better survival than those in the OR (adjusted HR 0.39, p=0.024, Figure 2). Importantly, the cause of death was cardiac in 16, non-cardiac in 25, and unknown in 8 patients. Of the known causes of death, only two were arrhythmic in nature, both in CRT-D recipients. Conclusions: In this long-term analysis, we identified no difference in survival between older CRT-P and CRT-D recipients. Most deaths were non-cardiac in origin and only 2 were arrhythmic in nature in CRT-D recipients. Our data support the use of the smaller and less expensive CRT-P device in older patients eligible for CRT therapy who have no prior history of ventricular arrhythmia. These findings should be tested in a larger pivotal trial.