Association of Risk Factors and Cardiac Outcomes in Patients With Primary Prevention of Sudden Cardiac Death: HINODE Study Sub Analysis.

Introduction: Primary analysis of the HINODE study revealed that mortality and ventricular tachyarrhythmia event rates for patients with primary prevention of sudden cardiac death in Japan were comparable to those of Western patients. Sub-analysis aimed to evaluate event rates in relation to accumulated risk factors (RFs) (left ventricular ejection fraction ≤ 35%, New York Heart Association class III/IV, left bundle branch block/wide QRS, renal dysfunction, diabetes, atrial fibrillation, myocardial infarction, age > 70 years, and smoking).

Methods and results: Implantable cardioverter defibrillator (ICD) (N = 102) and cardiac resynchronization therapy-defibrillator (CRT-D) (N = 69) enrollees were evaluated for first appropriately treated ventricular tachycardia or fibrillation (VT/VF), recurrent heart failure (HF) hospitalizations, and all-cause mortality. Event rates were compared for patients with lower-risk (2-3 RFs) and higher-risk (4-5 RFs) using time to event analyses. The ICD-cohort contained 50 (49%) lower-risk and 52 (51%) higher-risk patients, and the CRT-D-cohort 21 (30%) lower-risk and 48 (70%) higher-risk patients. Over 24 months, no significant difference was observed in the VT/VF event rate among the higher-risk group compared to the lower-risk group for either device cohort (ICD: 17% vs. 10%, p = 0.61; CRT-D: 6% vs. 5%, p = 0.79). Similarly, no significant difference was observed in the rate of all-cause mortality, although higher-risk patients trended towards more mortality (ICD: 15% vs. 7%, p = 0.15; CRT-D: 13% vs. 5%, p = 0.33) For the ICD cohort, the risk of HF hospitalization was 2.24 (95% CI: 1.24-4.03) times greater in the higher-risk group compared to the lower-risk group and among those hospitalized for HF, the length of stay was significantly longer for the higher-risk group (median 27 days per year vs. 10 days per year, p = 0.013). No significant difference in the rate of HF hospitalizations was detected for the CRT-D cohort.

Conclusion: The implantation of ICD should be considered despite the number of RFs to prevent sudden cardiac death. Proper CRT-D implantation may reduce the number of RFs over time and shorten the duration of HF-hospitalization.