Optimizing Patient Selection for Cardiac Resynchronization Therapy With or Without Defibrillator in a Multicenter Study of Japanese Patients　- Assessment of the MADIT-ICD Benefit Score.

Background: Although the MADIT-ICD benefit score (MBS) helps select suitable implantable cardioverter defibrillator (ICD) candidates, optimal indicators for cardiac resynchronization therapy (CRT) remain uncertain. Evaluating the applicability of the MBS in Japanese CRT patients is imperative.
Methods and Results: This multicenter study assessed the cumulative incidence of ventricular tachycardia/fibrillation (VT/VF) and non-arrhythmic mortality (AM) in CRT patients grouped according to potential benefit (lowest, highest, and intermediate). Among 400 primary prevention patients (mean age 65 years, 76% male), VT/VF occurred in 4 (7%), 68 (24%), and 14 (23%) patients in the lowest-, intermediate-, and highest-benefit groups, respectively (P=0.027), over a median follow-up of 34 months. Non-arrhythmic death was observed in 15 (25%), 91 (33%), and 9 (15%) patients in the lowest-, intermediate-, and highest-benefit groups, respectively (P=0.025). Multivariate analysis identified VT/VF score ≥7 (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.09-4.19; P=0.027) as a significant VT/VF predictor. The presence of left bundle branch block (HR 0.51; 95% CI 0.29-0.92; P=0.025) was associated with a reduced risk of VT/VF events. Non-AM score ≥3 (HR 1.70; 95% CI 1.01-2.88; P=0.047), systolic blood pressure <100 mmHg (HR 1.84; 95% CI 1.25-2.70; P=0.002), and estimated glomerular filtration rate <30 mL/min/1.73 m ² (HR 1.98; 95% CI 1.23-3.20; P=0.005) were significant predictors of non-arrhythmic death.
Conclusions: The MBS can identify suitable candidates for CRT-D among Japanese individuals.