Left ventricular ejection fraction overcrossing 35% after one year of cardiac resynchronization therapy predicts long term survival and freedom from sudden cardiac death: single center observational experience

Background Reverse remodeling and increased LVEF after CRT correlate with survival and heart failure hospitalizations, but their relationship with the risk of SCD is unclear. We aimed to evaluate whether exceeding a threshold value of 35% for left ventricular ejection fraction (LVEF) 1 year after cardiac resynchronization therapy (CRT) predicts survival and freedom from sudden cardiac death (SCD). Methods 330 patients who survived ≥ 6 months after CRT (males 80%, age 62 ± 11 years) were grouped according to 1-year LVEF ≤ 35% (Group 1, n = 187, 57%) or > 35% (Group 2, n = 143, 43%). According to changes vs. baseline (reduction of left end-systolic volume [LVESV] ≥ 10% or increase of LVEF% > 10 units), patients were also classified as echocardiographic (Echo) non-responders (Group A, n = 152, 46%) or responders (Group B, n = 178, 54%). Results At baseline, LVESV volume was larger and LVEF was lower in Group 1 vs. Group 2 (p < 0.001). After 1 year, echocardiographic improvement was greater in Group 2 vs. Group 1 (p < 0.001 for changes in both LVESV and LVEF). Over a median follow-up of 49 months, 47 patients (14%) died, 36 in Group 1 vs. 11 in Group 2 (19% vs. 8%, p = 0.004). A significantly higher rate of freedom from all-cause mortality (p = 0.002), cardiovascular mortality (p < 0.001) and SCD (p < 0.001) was observed in Group 2. Multivariate analysis demonstrated that only 1-year LVEF > 35% was associated with freedom from SCD/VF. Conclusions LVEF > 35% after 1 year of CRT characterizes a favorable long-term outcome, with a very low risk for SCD.