Speckle-Tracking Echocardiography in Children With Duchenne Muscular Dystrophy: A Prospective Multicenter Controlled Cross-Sectional Study

Background: Prognosis of Duchenne muscular dystrophy (DMD) is related to cardiac dysfunction. Speckle-tracking echocardiographic (STE) imaging is emerging as a noninvasive functional biomarker to consider in the early detection of DMD-related cardiomyopathy. However, STE analysis has not been assessed in a prospectively controlled study, especially in presymptomatic children with DMD, and no study has used STE analysis in all three displacements (longitudinal, radial, and circumferential) and for both ventricles. Methods: This prospective controlled study enrolled 108 boys, 36 of whom had DMD (mean age, 11 +/- 3.8 years) and 72 of whom were age-matched control subjects in a 1: 2 case-control design. Conventional echocardiographic variables were collected for the left and right ventricles. STE analyses were performed in the longitudinal, radial, and circumferential displacements for the left ventricle and in the free wall longitudinal displacement for the right ventricle. The effect of age on the evolution of two-dimensional strain in children with DMD was studied by adding an interaction term, DMD x age, in the models. Results: Conventional echocardiographic measures were normal in both groups. Left ventricular (LV) ejection fraction ranged from 45% to 76% (mean, 63 +/- 6%) in the DMD group and from 55% to 76% (mean, 64 +/- 5%) in the control group. Global LV strain mean measures were significantly worse in the DMD group for the longitudinal (-16.8 +/- 3.9% vs -20.6 +/- 2.6%, P < .0001), radial (22.7 +/- 11.3% vs 31.7 +/- 14%, P = .002), and circumferential (-16.5 +/- 3.8% vs -20.3 +/- 3.1%, P < .0001) displacements. The decrease of global LV longitudinal strain with age in children with DMD was 0.34% per year more marked than that in control subjects. The LV inferolateral and anterolateral segments were specifically impaired, especially in the basal area. Right ventricular function evaluated using conventional echocardiography and STE analysis was normal and not different between children with DMD and control subjects. Conclusions: The existence of altered LV strain despite normal LV function in children with DMD represents an important perspective for future pediatric drug trials in DMD-related cardiomyopathy prevention.