Left Ventricular Reverse Remodeling in Cardiac Resynchronization Therapy and Long-Term Outcomes

Abstract Objectives The aim of this study was to evaluate the association between improvement in left ventricular end-systolic volume (LVESV) with cardiac resynchronization therapy (CRT) and mortality and whether this relationship was modified by the presence of a left bundle branch block (LBBB) electrocardiographic pattern. Background Left ventricular reverse remodeling in patients receiving CRT has been shown to predict outcomes. However, the extent to which reverse remodeling contributes to long-term survival is not well understood. Methods Changes in LVESV were assessed in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) patients receiving CRT with a defibrillator (CRT-D) and echocardiograms available at 1 year (n = 752), stratified by LBBB, relative to long-term all-cause mortality, compared with those with implantable cardioverter-defibrillators (ICDs) only (n = 684). Results In patients with LBBB, a reduction in LVESV of >35% (median) translated into significantly lower risk for long-term mortality (hazard ratio [HR]: 0.34; p  27.6%). CRT-D patients without LBBB with the least reverse remodeling (quartile 1) had a more than 3-fold increased risk for death compared with those with ICDs only (HR: 3.11; p  Conclusions In patients with LBBB, CRT-D-induced reduction in LVESV at 1 year is associated with long-term survival benefit. Despite left ventricular reverse remodeling with CRT-D, there is no survival benefit and potential harm in patients without LBBB.