Long-term outcome with cardiac resynchronization therapy in mild heart failure patients with left bundle branch block from US and Europe MADIT-CRT.

Abstract

Early intervention with cardiac resynchronization therapy with defibrillator (CRT-D) in mild heart failure (HF) patients with a left bundle branch block (LBBB) ECG pattern was associated with a significant reduction in mortality in the long-term MADIT-CRT trial. Whether patients in MADIT-CRT enrolled from centers in the USA and in Europe have different long-term clinical response to CRT-D remains unknown. We compared the baseline clinical characteristics and clinical and echocardiographic long-term clinical response to CRT-D between MADIT-CRT patients with LBBB who were enrolled in USA (n=871) and European centers (n=392). Although European patients had more advanced heart disease than US patients, CRT-D was associated with similar 60% (p<0.001) reductions in the risk of HF in US and European patients when compared to ICD-only therapy after adjustment for relevant baseline clinical covariates. US patients had significant long-term mortality reduction (38%, p=0.02) while among European patients the survival benefit associated with CRT-D was not statistically significant (HR 0.73, p=0.18); subgroup analyses revealed a significantly greater CRT-D benefit among women who were enrolled in the USA, whereas no significant gender difference in the clinical benefit of CRT-D was observed in the European cohort. Reverse remodeling at 1year was associated with significantly better clinical outcomes in both groups. Despite differences in baseline disease severity, European and US patients with LBBB experienced a similar clinical and echocardiographic response to cardiac resynchronization therapy during long-term follow-up. http://clinicaltrials.gov/ct2/show/NCT00180271 .