Abstract 9184: Reduction in Mortality among Patients with Left Bundle Branch Block Treated with Cardiac Resynchronization Therapy: Results from the MADIT-CRT Trial
MADIT-CRT demonstrated a reduction in a composite endpoint, first occurrence of worsening heart failure or death, in mildly symptomatic patients with advanced left ventricular dysfunction receiving cardiac resynchronization therapy combined with an ICD (CRT-D) relative to similar patients receiving only an ICD in an average 2.4 year follow-up. Mortality in the short-term follow-up was not different between treatment groups. With additional follow-up, averaging 3.6 years since device implant, 191 deaths occurred among the 1820 enrollees. Among all study patients and among the 536 patients with baseline conduction defects other than left bundle branch block (LBBB), death rates were still not different in subjects receiving CRT-D or ICD. Among the 70% of patients with left bundle branch block (LBBB; n=1281) at baseline, extended follow-up revealed a statistically significant reduction in death (p=0.047) in patients receiving CRT-D relative to those receiving ICD alone (see Kaplan-Meier graph). The Forest plot shows the consistency of reduction in mortality with CRT-D therapy in almost all LBBB subgroups, especially in females. In conclusion, extended follow-up in MADIT-CRT showed that CRT-D reduced mortality in mildly symptomatic patients with LBBB, sinus rhythm, EF ≤30%, and QRS≥130 msec. This life-saving benefit of CRT-D was evident in almost all LBBB subgroups, but it was not seen in any of the subgroups of patients without LBBB.
- © 2011 by American Heart Association, Inc.