Applicability of the MADIT-CRT Score for Prediction of the Long-Term Clinical benefit of the Cardiac Resynchronization Therapy by QRS Morphology

Background – We have previously shown that a response score, including 7 baseline clinical and echocardiographic factors, can be used to predict CRT-D benefit among patients enrolled in MADIT-CRT over a median of 2.4 years. We aimed to evaluate the yield of the score for the assessment of the long-term clinical outcome among patients with left bundle branch block (LBBB) and those without LBBB.

Methods – The study comprised 1751 patients with long-term follow up (mean 4.6 ± 1.7 years). Patients were categorized into two groups: low and high responders (divided by the median response score). The primary endpoint for clinical outcome was defined as first heart failure (HF) event or death, whichever came first. The secondary endpoints were death alone or ventricular tachyarrhythmic events (VTE).

Results – In the LBBB group, multivariate analysis showed that CRT-D vs. ICD-only therapy was associated with greater reduction in the risk of HF or death among high responders (64% risk-reduction; p<0.001) compared with low responders (40% risk-reduction ;p

Conclusion – The MADIT-CRT response score can be used to identify mildly symptomatic HF patients with LBBB who will derive enhanced long term clinical benefit from cardiac resynchronization, but it has no predictive value among patients without LBBB.