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.

ABSTRACT

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.