Left Atrial Reservoir Strain for Predicting Progression to End-Stage in Hypertrophic Cardiomyopathy

AIMS: End-stage hypertrophic cardiomyopathy (HCM), defined as a left ventricular (LV) ejection fraction (LVEF) < 50%, is associated with poor prognosis; however, predictors of progression remain unclear. We aimed to identify prognostic factors for progression to end-stage HCM. METHODS AND RESULTS: We analyzed 925 patients with HCM between 2007 and 2023 who underwent ≥1 year of follow-up echocardiography. The primary outcome was progression to end-stage HCM, defined as an LVEF <50% without reversible causes. A CMR subcohort included 491 patients with baseline CMR. During a median follow-up of 6.5 years (IQR: 3.3-10.7), 35 patients (3.8%) progressed to end-stage HCM (10-year cumulative incidence: 4.4%, 95% CI: 2.5-6.2%). LVEF, LV apical aneurysm, and LARS were independent predictors of progression to end-stage HCM (per 1% decrease in LARS: adjusted HR 1.10, 95% CI 1.04-1.17, p < 0.001), and impaired LARS (<16.9%) was associated with a higher risk. In the CMR subcohort, LARS remained an independent predictor after adjusting for late gadolinium enhancement (LGE%) (adjusted HR 1.11, 95% CI 1.02-1.20, p = 0.011). Adding LARS to a model including LVEF, LV apical aneurysm, and LA size yielded significant incremental prognostic value (global χ2 27.1 to 40.1; p < 0.001). Similar incremental value was observed in models including LGE% in the CMR subcohort. After progression to end-stage HCM, prognosis was poor, with 2-year cardiovascular event-free survival rate of 71.0%. CONCLUSIONS: Progression to end-stage HCM is infrequent but associated with poor prognosis. Impaired LARS independently predicts disease progression beyond conventional markers, supporting its role in risk stratification.