Long-term cardiac reverse remodeling after cardiac resynchronization therapy

Abstract

Introduction: The benefit of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) have been observed in the first year. However, there are few data on long-term follow-up and the effect of changes of LVEF on mortality. This study aimed to assess the LV remodeling after CRT implantation and the probable effect of changes in LVEF with repeated measures on mortality over time in a real-world registry.

Methods: Among our cohort of 328 consecutive CRT patients, mixed model effect analysis have been made to describe the temporal evolution of LVEF and LVESV changes over time up with several explanatory variables. Besides, the effect of LVEF along time on the probability of mortality was evaluated using joint modeling for longitudinal and survival data.

Results: The study population included 328 patients (253 men; 70.2 ± 9.5 years) in 4.2 (2.9) years follow-up. There was an increase in LVEF of 11% and a reduction in LVESV of 42 mL during the first year. These changes are more important during the first year, but slight changes remain during the follow-up. The largest reduction in LVESV occurred in patients with left bundle branch block (LBBB) and the smallest reduction in patients with NYHA IV. The smallest increase in LVEF was an ischemic etiology, longer QRS, and LV electrode in a nonlateral vein. Besides, the results showed that the LVEF profiles taken during follow-up after CRT were associated with changes in the risk of death.

Conclusion: Reverse remodeling of the left ventricle is observed especially during the first year, but it seems to be maintained later after CRT implantation in a contemporary cohort of patients. Longitudinal measurements could give us additional information at predicting the individual mortality risk after adjusting by age and sex compared to a single LVEF measurement after CRT.

Keywords: cardiac resynchronization therapy; heart failure; long‐term follow‐up; ventricular remodeling.

FIGURE 1

Evolution of changes in left ventricular ejection fraction (LVEF) and left ventricular end‐systolic volume (LVESV) during follow‐up

FIGURE 2

Effects of LVEF and LVESV changes on mortality risk. Interpretation: Taking the value of 5 on the X axis as the reference value for the change in LVEF, the logarithm of the relative risk of mortality for the change in LVEF is shown. For example, a 30‐point improvement in LVEF decreases the log RR by −1, which means that the relative risk of death is 2.72 times lower than a 5‐point improvement in LVEF. For the LVESV value, the reference value is 15. For LVESV reductions of 30, they will present a reduction in the relative risk of mortality 2.72 times greater than changes in LVESV of 15 (the number e, used as the base for a logarithm, is approximately equal to 2.72)

FIGURE 3

Evolution of the change of LVEF (A) and LVESV (B) adjusted for confounding variables over time (LVEF: P < .001 with 2.42 degrees of freedom; LVESV: P < .001 with 2.45 degrees of freedom)