Background: The prospective observational Nippon Storm Study aggregated clinical data from Japanese patients receiving implantable 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 proportional 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 significantly 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.
Keywords: Electrical storm; Implantable cardioverter-defibrillator; Non-ischemic heart failure; Propensity score matching; Prophylactic implantable cardioverter defibrillator (ICD) therapy.