Optimizing patient selection for cardiac resynchronization therapy in a multicenter study of Japanese patients: assessment of the MADIT-ICD benefit group
Authors: Sato H , Noda T , Yamamoto N , Ueda N , Nakano M , Ito T , Chiba T , Hasebe Y , Kamakura T , Ishibashi K , Kusano K , Yasuda S 
Published: October 2024

Abstract

Background
The MADIT-ICD benefit group, derived from ventricular tachycardia (VT)/ventricular fibrillation (VF) scores and non-arrhythmic mortality scores (Table 1), facilitates the appropriate selection of candidates for implantable cardioverter-defibrillator (ICD) therapy. While the 2021 European Society of Cardiology Guidelines have discussed the advantages and considerations of adding a defibrillator in patients undergoing cardiac resynchronization therapy (CRT), the optimal selection of CRT with or without a defibrillator remains unclear, particularly in Asian populations. This is especially relevant for primary prevention using ICD, which is characterized by fewer cases of ischemic etiology compared to Western countries.

Purpose
This study aimed to evaluate the utility of the MADIT-ICD benefit group in Japanese CRT patients and identify key indicators for determining the necessity of CRT with or without a defibrillator.

Methods
We conducted a retrospective, multicenter evaluation of 505 consecutive Japanese CRT patients enrolled between 2012 and 2020. Among these patients, 76% were male, with a mean age of 65 years and a mean body mass index of 22.5 kg/m2. Ischemic etiology was present in 25% of patients, with 20% undergoing secondary prevention. The study assessed the cumulative incidences of VT/VF and non-arrhythmic mortality based on the MADIT-ICD benefit group (lowest, intermediate, and highest). Predictors for each outcome were explored, and the MADIT-ICD benefit group was validated in the Japanese cohort.

Results
Of the 400 included patients, 60 (15%) were categorized into the lowest MADIT-ICD benefit group, 279 (70%) into the intermediate group, and 61 (15%) into the highest group. Over a median follow-up period of 34 months, VT/VF occurred in 4 (13%), 68 (24%), and 14 (23%) patients in the lowest, intermediate, and highest benefit groups, respectively (Gray’s test, P = 0.027, Figure 1A). Non-arrhythmic death occurred in 15 (25%), 91 (33%), and 9 (15%) patients in the lowest, intermediate, and highest benefit groups, respectively (Log-rank test, P = 0.025, Figure 1B). Multivariable analysis identified MADIT-ICD VT/VF score (hazard ratio [HR] 1.23; 95% confidence interval [CI] 1.12-1.35; P &lt; 0.001) and left bundle branch block (LBBB) (HR 0.48; 95% CI 0.27-0.86; P = 0.014) as significant predictors for VT/VF, while MADIT-ICD non-arrhythmic mortality score (HR 1.16; 95% CI 1.07-1.27; P &lt; 0.001), serum creatinine (Cr) (HR 1.28; 95% CI 1.13-1.45; P &lt; 0.001), and mineral corticoid receptor antagonist (MRA) use (HR 1.84; 95% CI 1.21-2.79; P = 0.004) were significant predictors for non-arrhythmic death (Table 2).

Conclusion
The MADIT-ICD benefit group, in conjunction with left bundle branch block and renal function, may serve as valuable predictors for determining the necessity of cardioverter-defibrillator therapy in Japanese CRT patients.Table 1 and Figure 1