Cardiac Resynchronization Therapy Associated With Improved Survival in Advanced Transthyretin Cardiac Amyloidosis Despite Higher Disease Severity.

Transthyretin cardiac amyloidosis (ATTR-CM) frequently affects native conduction, necessitating permanent pacemaker (PPM), implantable cardioverter-defibrillator, or cardiac resynchronization therapy (CRT) implantation. This study characterizes right ventricular pacing (RVP) burden in ATTR-CM patients and evaluates its impact on left ventricular ejection fraction (LVEF), heart failure (HF) rehospitalization, and survival. Retrospective chart review of ATTR-CM patients requiring device implantation (4/2012 to 9/2022). Patients were categorized by pacing burden: low RVP (pacing burden <40%, N = 31), high RVP (≥40%, N = 38), and CRT (N = 36). Fine-Gray models were used for survival analysis; incidence rate ratios (IRRs) evaluated HF rehospitalization. Models were adjusted for age, race, gender, National Amyloidosis Center (NAC) staging, initial LVEF, and atrial fibrillation. A total of 105 patients with mean age 80 ± 8 years, 75% male, 67% Caucasian, were followed up for median 3.1 (interquartile range: 1.3 to 4.9) years. NAC Stage II/III were more prevalent in high RVP (65%) and CRT (80%) versus low RVP (55%). High RVP showed significantly increased HF rehospitalization versus low RVP (IRR 5.76, p < 0.001). CRT had higher rehospitalization than low RVP (IRR 3.35, p < 0.001) but similar to high RVP (IRR 1.72, p = 0.106). High RVP demonstrated worse survival versus low RVP (hazard ratio [HR] 6.24, p < 0.001). CRT showed better survival than high RVP (HR 3.03, p = 0.005) with no difference versus low RVP. Independent mortality predictors included NAC Stage III (HR 4.81, p < 0.001), atrial fibrillation (HR 2.01, p = 0.028), and lower initial LVEF (HR 1.03, p = 0.006). High RVP burden is associated with increased HF rehospitalization and mortality in ATTR-CM. CRT implanted upfront demonstrated superior survival compared to high RVP, suggesting a benefit for ATTR-CM patients with high pacing needs and NAC Stage II/III, warranting further investigation.