Evaluation of Early Left Ventricular Dysfunction in Patients with Duchenne Muscular Dystrophy Using Two-Dimensional Speckle Tracking Echocardiography and Tissue Doppler Imaging.

ABSTRACT

Although progressive cardiac dysfunction is the leading cause of death in patients with Duchenne muscular dystrophy (DMD), their cardiac function measured by conventional echocardiography has been generally interpreted as normal at a young age. We aimed to determine whether two-dimensional speckle tracking echocardiography (STE) or tissue Doppler imaging (TDI) could be used for early identification and detection of cardiac dysfunction in young patients with DMD. Thirteen pediatric patients (mean age, 9.69 ± 2.2 years) with DMD and 26 age-matched healthy children (mean age, 9.65 ± 2.2 years) were included in the study. All patients were examined via conventional echocardiography, TDI, and STE. Standard echocardiographic measurements of left ventricular (LV) systolic and diastolic function were obtained. Myocardial velocities including peak-systolic and early- and late-diastolic myocardial velocities were calculated in longitudinal direction in the interventricular septum, using TDI. Speckle tracking analyses were performed by acquiring apical four-, three-, and two-chamber views with the highest possible frame rates. Conventional parameters were similar between the two groups, but heart rates were higher in patients with DMD than in controls. The results of LV diastolic function evaluated using TDI showed that annular peak velocity during early diastole (e'; 10.9 ± 1.7 vs. 14.6 ± 1.7 cm/s), e'/a' ratio (2.0 ± 0.5 vs. 3.0 ± 0.5), E/e' ratio (9.4 ± 1.4 vs. 7.3 ± 0.8), and myocardial performance index (0.46 ± 0.05 vs. 0.36 ± 0.06) of the mitral septal annulus among patients with DMD differed significantly from those of healthy children. A significant decrease in global longitudinal systolic strain was found in patients with DMD (- 16.6 ± 3.7 vs. - 21.2 ± 2.1), with a marked decrease in the LV basal inferolateral and basal inferior walls. In young patients with DMD who have global normal systolic function, reductions in systolic deformation parameters as well as reduced early diastolic myocardial velocities can be detected particularly in the basal inferolateral LV walls. The prognostic significance of these findings warrants further longitudinal follow-up.