Enhanced risk stratification in hypertrophic cardiomyopathy through the integration of extracellular volume fraction on cardiovascular magnetic resonance

Abstract Background Myocardial scar and diffuse interstitial fibrosis can be assessed non-invasively using late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) on contrast-enhanced cardiovascular magnetic resonance (CMR). While extensive LGE is an established marker for sudden cardiac death (SCD) and heart failure (HF) in hypertrophic cardiomyopathy (HCM), the prognostic value of ECV remains unclear. Purpose This study investigated the incremental prognostic value of ECV beyond LGE in patients with HCM. Methods Consecutive HCM patients undergoing CMR in 2012–2024 were analyzed. LGE and global ECV were quantified, and their associations with the primary endpoint of HCM-related events–a composite of SCD events, HF events, and HCM-related death–were examined. Results Among 990 patients (median age 58 [IQR 49–67] years; male 68.3%), 64 (6.5%) experienced the primary endpoint over a median follow-up of 3.2 (IQR 1.3–5.8) years. LGE (median 7.1%, IQR 2.3–16.9%) and ECV (median 29.0%, IQR 26.6–32.0%) were moderately correlated (R=0.604, p