Abstract 4369875: The Association Between Cardiac Resynchronization Therapy and Survival in Patients with Cardiac Amyloidosis: A Multicenter Retrospective Study.

Background: Cardiac amyloidosis (CA) patients with reduced left ventricular ejection fraction (EF) are at increased risk for mortality. The benefit of cardiac resynchronization therapy (CRT) in terms of mortality reduction has not been established in this population. Aim: To evaluate the survival benefit of CRT, either CRT-D or CRT-P, in a large cohort of patients with cardiac amyloidosis and reduced EF. Methods: We retrospectively analyzed patients with confirmed CA and reduced EF (<40%) between 2009 and 2023 across Mayo Clinic sites. Patients were stratified into three groups: no device, CRT with pacemaker function (CRT-P), and CRT with defibrillator function (CRT-D). CRT devices were indicated for low ejection fraction less than 40% and patients who had chronic heart failure with a wide QRS. Kaplan-Meier survival estimates were generated, and log-rank tests were used for comparison. A secondary analysis was conducted combining CRT-P and CRT-D versus no device (EF <40%), and a tertiary analysis compared CRT-P versus CRT-D. Results: Among 184 patients [36 AL (20%), 148 ATTR (80%)], 38 (19%) had no cardiac device and EF <40%, 20 (11%) received CRT-P, and 116 (63%) received CRT-D. The median follow-up was 3.4 years (1.7, 5.0). The probability of survival was significantly higher in the CRT group compared to the no device-EF<40 group (Log Rank p=0.013; figure B). Among patients receiving CRT, there was no significant difference in all-cause mortality between those receiving CRT-P and those receiving CRT-D (Log Rank p=0.5; figure C). Conclusion: In patients with cardiac amyloidosis and reduced EF, CRT is associated with significantly improved survival compared to no device. No mortality difference was observed between CRT-P and CRT-D. Prospective studies are warranted.