The Pursuit of Improved Arrhythmic Risk Stratification in Nonischemic Cardiomyopathy: Are We Getting Any Closer?

Sudden cardiac death (SCD) caused by ventricular tachyarrhythmias is a significant contributor to mortality in patients with nonischemic cardiomyopathy (NICM). Although implantable cardioverter-defibrillators (ICDs) represent an effective treatment against hemodynamically significant ventricular arrhythmias (VAs), the targeting and application of ICD in NICM patients remains controversial. Current tools for the identification of patients likely to benefit from ICDs, mainly based on left ventricular ejection fraction (LVEF), are blunt so that most patients receiving such devices never use them. Indeed, current practice may result in overtreatment of patients with low arrhythmic risk, despite having an LVEF of <35%, and undertreatment of others at very high risk of SCD, such as those with genetically determined forms of malignant NICM, despite the presence of mildly reduced or near-normal LVEF.