Predicting sudden cardiac death in heart failure with reduced ejection fraction.

Sudden cardiac death (SCD) accounts for up to half of all mortality in patients with heart failure with reduced ejection fraction, yet contemporary clinical practice continues to rely primarily on left ventricular ejection fraction (LVEF) despite its well-recognized limitations as a predictor of arrhythmic risk. Many patients who experience SCD have only mildly reduced or even preserved LVEF, while a substantial proportion with severely reduced LVEF never develop life-threatening arrhythmias, underscoring the need for more precise risk assessment tools. This review synthesizes current evidence on clinical features, comorbidities, biomarkers, electrocardiographic abnormalities, and advanced imaging markers that independently inform SCD risk, including high-risk indicators such as syncope, chronic kidney disease, ventricular arrhythmias, impaired global longitudinal strain, and myocardial fibrosis on cardiac MRI. We also summarize emerging multiparametric risk models that integrate these variables into clinically usable frameworks, offering more individualized risk estimates than ejection fraction alone. Finally, we outline contemporary prevention strategies that optimize guideline-directed medical therapy and targeted device therapy, while discuss the evolving role of precision-medicine approaches in guiding ICD decision-making. Collectively, these data highlight the importance of moving beyond LVEF-centric algorithms toward more nuanced, multimodal strategies to better identify high-risk patients and reduce the ongoing burden of SCD in heart failure patients.