Myocardial strain changes in Duchenne muscular dystrophy without overt cardiomyopathy

Patients with Duchenne muscular dystrophy (DMD) are at risk of the development of dilated cardiomyopathy and heart failure, thus making early identification of high-risk patients necessary. Myocardial strain imaging (MSI) can be used for quantitative analysis of wall motion of the left ventricle (LV). The aim of this study was to determine whether MSI could detect early changes in myocardial properties in presymptomatic DMD patients with normal LV function.

Two-dimensional echocardiographic and tissue Doppler examinations were performed in 13 DMD patients (age range, 11 to 20 years) with normal LV function and in 10 healthy controls. MSI was obtained from tissue Doppler information. In control subjects, strain values in both inner and outer layers of the myocardium were positive at the short-axis image showing the radial systolic thickening. In 10 of the 13 DMD patients, however, myocardial strain showed a negative strain value in systole in the outer layer of the posterolateral wall at the parasternal short-axis image for each cardiac cycle. In 5 of these 10 patients, the timing of the peak systolic velocity at the inferoposterior wall was delayed more than 60 ms than that at the posterolateral wall (mean 80.0+/-17.5 ms).

In some DMD patients with normal LV function, myocardial strain profiles at the posterolateral wall of the LV were different from those in healthy controls, suggesting abnormal myocardial contraction. MSI appears to detect early changes in myocardial features in DMD patients before the onset of overt cardiomyopathy.