Sudden death risk stratification in non-ischemic dilated cardiomyopathy using old and new tools: a clinical challenge

Introduction: Risk stratification for sudden cardiac death in non-ischemic dilated cardiomyopathy (NIDCM) remains a clinical challenge. Areas covered: Currently, left ventricular ejection fraction (LVEF), severity of heart failure symptoms according to NYHA classification, and morphology and duration of the QRS complex guide device management in these patients with implantation of a cardioverter defibrillator (ICD) and/or cardiac resynchronization therapy (CRT) devices. Recently, the results of a randomized trial stirred some controversy regarding the utility of ICD in NIDCM patients, however, a subsequent meta-analysis confirmed prior findings of the survival-prolonging benefit of device therapy. Newer risk markers, like late gadolinium enhancement in cardiac magnetic resonance imaging (CMR) detecting myocardial fibrosis, are encouraging in improving risk stratification in these patients. Furthermore, resurgence of an old tool, the electrophysiology study (EPS), and technical advances in genetics in identifying highrisk familial NIDCM, appear promising in this direction. Expert commentary: Based on old and new tools, a more individualized approach may be applied in NIDCM patients, whereby CMR, EPS and genetics may provide further guidance, particularly in patients with LVEF>35%. These issues are herein reviewed and a practical algorithm is proposed for risk stratification and device implantation in NIDCM patients with LVEF below and above 35%.