No single imaging, clinical, or electrophysiologic marker has achieved guideline-level validation to replace LVEF for sudden cardiac death risk stratification in nonischemic dilated cardiomyopathy.
Do multimodal risk stratification strategies improve the prediction of sudden cardiac death in patients with non-ischemic dilated cardiomyopathy compared to LVEF alone?
Current guidelines still rely on LVEF ≤35% for primary prevention ICD candidacy in NICM, but emerging tools like CMR LGE and genetic testing are increasingly recognized as valuable adjuncts for sudden cardiac death risk stratification.
Risk stratification for sudden cardiac death (SCD) in non-ischemic dilated cardiomyopathy (NICM) and a left ventricular ejection fraction (LVEF) ≤35%. remains controversial. The value of a low LVEF alone is limited, as it cannot distinguish between arrhythmic and nonarrhythmic mortality. This led to further investigation into markers of electrical instability. Prior studies have evaluated noninvasive and invasive markers, including ambient arrhythmias, signal-averaged ECG, QT dispersion, T-wave alternans, heart rate variability, and programmed ventricular stimulation. None of these markers have consistently improved the predictive accuracy for SCD beyond LVEF. Cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) has emerged as a tool for substrate characterization, with myocardial fibrosis burden and LGE patterns associated with SCD, arrhythmic events, as well as appropriate therapies in patients with implantable cardioverter-defibrillators. Quantitative LGE thresholds and integrated CMR-based models may enhance SCD risk discrimination, although methodological heterogeneity, scanner-dependent quantification, and lack of randomized trials challenge the inclusion of CMR parameters in current guidelines. Emerging tiered approaches like the ReCONSIDER framework, combining noninvasive markers, CMR tissue characterization, and electrophysiologic testing to capture the heterogeneity of NICM, may also be of value. However, at the present time, no single imaging, clinical, or electrophysiologic marker has achieved guideline-level validation as an adjunct or a replacement for LVEF. Future studies may focus on standardizing CMR acquisition and quantification, prospective validation of multimodal risk models, and assessment of dynamic, serial biomarkers to establish a more accurate approach to SCD risk stratification in NICM.
Bradel et al. (Wed,) conducted a review in Non-ischemic dilated cardiomyopathy. Multimodal risk stratification (CMR LGE, T1 mapping, genetics, electrophysiology) vs. LVEF ≤ 35% alone was evaluated. No single imaging, clinical, or electrophysiologic marker has achieved guideline-level validation to replace LVEF for sudden cardiac death risk stratification in nonischemic dilated cardiomyopathy.