Prognostic value of longitudinal ventricular strain changes in a contemporary cohort of muscular dystrophy

Introduction Cardiomyopathy is a leading cause of morbidity and mortality in patients with muscular dystrophies (MD), yet conventional echocardiographic indices may incompletely capture disease progression and treatment response. Myocardial strain imaging offers a sensitive assessment of cardiac function, but the prognostic significance of longitudinal strain changes in contemporary MD populations remains insufficiently characterized. We evaluated the association between longitudinal changes in myocardial strain and clinical outcomes in a contemporary MD cohort with guideline directed medical treatment (GDMT) for HF. Methods Adults with genetically confirmed MD and systolic dysfunction (LVEF < 50%) were retrospectively included at two European expert centers. To reflect contemporary management, the observation period extended from September 2021 through June 2024. Comprehensive echocardiography, including tissue Doppler and left ventricular (LV), right ventricular (RV), and left atrial (LA) strain, was performed at baseline and follow-up. ROC analysis was performed to identify optimal strain change thresholds for risk stratification. Associations between strain changes and the primary outcome (composite of HF hospitalization and cardiovascular death) were explored using Cox regression analysis. Results A total of 40 patients (median age 32 years, median LVEF 37.5%, 68% NYHA class II; 73% Duchenne MD) were included. At baseline, 83% received RASi, 63% beta-blockers, 38% MRA, and 13% SGLT2 inhibitors, with prescription rates increasing during follow-up. Patients treated with all 4 classes of GDMT exhibited lower LVEF at baseline (30% vs. 40%, p=0.007), consistent with treatment intensification in patients with more advanced dysfunction. In multivariable linear regression, therapy optimization was independently associated with improvement in LV strain (Standardized Beta = -0.33; [95%CI: -4.0/-0.1]; p=0.040), whereas no significant associations were observed for RV, LA strain, or LVEF. ROC curves analysis identified a ΔLV strain of −1.4% and a ΔRV strain of −2.3% (Youden index) as the optimal thresholds for risk stratification. Over a median follow-up of 19 (IQR 13-23) months, patients exhibiting ventricular strain changes at or below the ROC-derived thresholds (reflecting improvement or stabilization) had significantly lower risk of the primary outcome (LV-strain: HR 0.13 [95%CI: 0.03-0.53], p=0.004; RV-strain: HR 0.17 [95%CI: 0.04–0.80], p=0.024), while ΔLVEF and ΔRV-tissue Doppler (S’ wave) were not predictive of outcome. These associations persisted after adjustment for baseline ventricular function and NT-proBNP. Conclusion In this contemporary MD cohort with systolic dysfunction, longitudinal changes in ventricular strain were associated with clinical events independently of conventional severity indices.