Abstract 14687: Altered Left Ventricular Hemodynamic Forces as an Early Indicator of Disease Progression in Duchenne Muscular Dystrophy

Introduction: Duchenne muscular dystrophy (DMD) patients develop progressive cardiomyopathy. Cardiac magnetic resonance (CMR) imaging can identify global/regional dysfunction and myocardial fibrosis, although left ventricular (LV) biomechanics are not conventionally assessed. Thus, we investigated hemodynamic force (HDF), a novel measurement of the intraventricular pressure gradient, as potential biomarker for myocardial dysfunction in DMD.

Methods: Prospective, multi-center study of DMD patients and age-matched controls. Feature-tracking (Qstrain, Medis) performed on short/long-axis cine to capture LV wall motion. Novel diffeomorphic mapping used to generate kinematic models and calculate HDF components (apical-basal, lateral-septal, anterior-posterior) throughout the cardiac cycle ( Figure 1A ). HDF was correlated to conventional CMR parameters.

Results: Thirty-six DMD and 10 controls included with LV ejection fraction (LVEF) 51±6% vs 56±6% (p = 0.037). DMD patients with normal LVEF had altered HDF across multiple points in each axis compared to controls ( Figure 1B ). Twenty-one DMD patients (58%) with LVEF < 55% had lower apical-basal (p = < 0.001), lateral-septal (p = 0.001), and anterior-posterior (p = 0.005) root mean square (RMS) HDF compared to DMD with normal LVEF (Figure 1C) . All components of HDF correlated with LV volumetric/strain parameters ( Table 1 ).

Conclusions: Cine-derived HDF are altered in DMD patients. Decreased systolic HDF and delay to peak diastolic HDF may be an early indicator of myocardial dysfunction compared to conventional CMR testing. Future studies will investigate HDF as a biomarker of disease progression.