Prognostic Impact of LGE Granularity Using CMR in End‑Stage Hypertrophic Cardiomyopathy

End-stage hypertrophic cardiomyopathy (HCM) is a distinct and advanced form of HCM, defined by a left ventricular ejection fraction <50% and associated with a markedly poor prognosis. Evidence on the prognostic relevance of late gadolinium enhancement (LGE) and its key features in end-stage HCM remains limited. The aim of our study was to evaluate the prognostic value of the LGE granularity model, including its location, extent, and pattern in patients with end-stage HCM.

All patients referred for cardiovascular magnetic resonance assessment of HCM at 3 French tertiary university hospitals between 2008 and 2024 were retrospectively screened, and all patients with a left ventricular ejection fraction <50% were included. The LGE granularity model was defined as a model combining LGE extent (unique versus multiple involvement), location (septal versus other), and pattern (subepicardial versus midwall). The primary end point was all-cause mortality.

Among 2873 patients with HCM, 691 (24%) with end-stage HCM were included (52±7 years, 54% male). After a median follow-up of 9 years (interquartile range, 6-11), 226 patients died (33%). LGE was observed in 259 (37%) patients and was associated with mortality, even after adjustment for classical prognostic factors (hazard ratio, 1.52 [95% CI, 1.07-2.18]; P=0.02). Each LGE granularity component was independently associated with mortality after adjustment: LGE extent (hazard ratio, 2.85 [95% CI, 1.03-7.85]; P=0.02), septal location (hazard ratio, 1.73 [95% CI, 1.10-2.73]; P<0.001), and midwall pattern (hazard ratio, 4.15 [95% CI, 1.79-9.61]; P<0.001).

In this large multicenter cohort of patients with end-stage HCM, the LGE granularity model integrating LGE extent, location, and pattern provided strong and independent prognostic value.