Regional Circumferential Strain is a Biomarker for Disease Severity in Duchenne Muscular Dystrophy Heart Disease: A Cross-Sectional Study

The aim of this study is to determine the contribution of strain epsilon (cc) in mid left ventricular (LV) segments to the reduction of composite LV circumferential epsilon (cc) in assess severity of duchenne muscular dystrophy (DMD) heart disease as assessed by cardiac magnetic resonance imaging (CMR). DMD patients and control subjects were stratified by age, LV ejection fraction, and late gadolinium enhancement (LGE) status. Tagged CMR images were analyzed for global ventricular function, LGE imaging, and composite and segmental epsilon (cc). The relationship between changes in segmental epsilon (cc) changes and LGE across patient groups was assessed by a statistical step-down model. LV epsilon (cc) exhibited segmental heterogeneity; in control subjects and young DMD patients, epsilon (cc) was greatest in LV lateral free wall segments. However, with increasing age and cardiac disease severity as demonstrated by decreased EF and development of myocardial strain the segmental differences diminished. In subjects with advanced heart disease as evidenced by reduced LV ejection fraction and presence of LGE, very little segmental heterogeneity was present. In control subjects and young DMD patients, epsilon (cc) was greatest in LV lateral free wall segments. Increased DMD heart disease severity was associated with reduced composite; epsilon (cc) diminished regional epsilon (cc) heterogeneity and positive LGE imaging. Taken together, these findings suggest that perturbation of segmental, heterogeneous epsilon (cc) is an early biomarker of disease severity in this cross-section of DMD patients.