Abstract 11912: Risk Stratification of Life Threatening Ventricular Tachyarrhythmias in Patients With Non-Ischemic Cardiomyopathy

Abstract

Background: The implantable cardioverter defibrillator is effective in reducing mortality among patients with heart failure (HF) due to ischemic heart disease. More recent clinical trial data have called into question the benefit of an ICD in patients with HF due to non-ischemic cardiomyopathy (NICM). Objective: The purpose of this study was to identify a risk stratification score among patients with NICM receiving a primary prevention ICD. Methods: The study population comprised 1842 patients with NICM who were enrolled in the MADIT and RAID trials. We used Fine and Gray analysis to develop a model for the occurrence of ventricular tachycardia/fibrillation (VT/VF), while accounting for the competing risk of death. Patients were grouped into 3 strata based on their risk score. Results: Five factors associated with increased risk of VT/VF were identified: ICD vs cardiac resynchronization therapy with a defibrillator (CRT-D), prior history of non-sustained VT, male gender, ejection fraction ≤ 25%, and Black Race. A score was generated based on this model and the patients were stratified into three risk groups. The four-year cumulative incidences of VT/VF in the low-, intermediate-, and high-risk groups were 19%, 37%, 52%, respectively (p<0.001 for the overall difference; Figure). Internal validation using a bootstrapping yielded a median c-statistic of 0.69 (95% CI 0.66-0.74). Conclusions: Our findings suggest that patients with NICM can be risk stratified for VT/VF using a combination of clinical and echocardiographic findings.