Effectiveness of Implantable Cardioverter Defibrillator in Patients With Non-Ischemic Heart Failure With Systolic Dysfunction

Background: The prospective observational Nippon Storm Study aggregated clinical data from Japanese patients receiving implant-able cardioverter-defibrillator (ICD) therapy. This study investigated the usefulness of prophylactic ICD therapy in patients with non-ischemic heart failure (NIHF) enrolled in the study. Methods and Results: We analyzed 540 NIHF patients with systolic dysfunction (left ventricular ejection fraction <50%). Propensity score matching was used to select patient subgroups for comparison; 126 patients were analyzed in each of the primary (PP) and secondary (SP) prophylaxis groups. The incidence of appropriate ICD therapy during follow-up in the PP and SP groups was 21.4% and 31.7%, respectively (P=0.044). The incidence of electrical storm (ES) was higher in SP than PP patients (P=0.024). Cox pro-portional hazard analysis revealed that increased serum creatinine in SP patients (hazard ratio [HR] 1.18; 95% confidence interval [CI] 1.02-1.33; P=0.013) and anemia in PP patients (HR 0.92; 95% CI 0.86-0.98; P=0.008) increased the likelihood of appropriate ICD therapy, whereas long-lasting atrial fibrillation in PP patients (HR, 0.64 [95% CI, 0.45-0.91], P=0.013) decreased that likelihood. Conclusions: In propensity score-matched Japanese NIHF patients, the incidence of appropriate ICD therapy and ES was signifi-cantly higher in SP than PP patients. Impaired renal function in SP patients and anemia in PP patients increased the likelihood of appropriate ICD therapy, whereas long-lasting atrial fibrillation reduced that likelihood in PP patients.