Background. Myocardial fibrosis occurs in the subepicardial myocardium of the left ventricular posterior wall in patients with Duchenne Muscular Dystrophy (DMD). The aim of this study was to clarify how these regional myocardial lesions might influence the focal cardiac movement using two-dimensional speckle tracking echocardiography and to investigate whether this new method is useful for the early detection of cardiac involvement in DMD patients.
Methods and Results. Twelve DMD patients with a normal fractional shortening (FS) of the left ventricle and twelve healthy age-matched control subjects were enrolled in this study. The segmental radial strain of the left ventricle was recorded using the two-dimensional tissue tracking echocardiography, and the systolic maximal strain was measured. Thereafter, the peak systolic maximal strain was separately measured in the inner-half and outer-half of the left ventricular posterior wall. In DMD patients, the systolic maximal radial strain of the septum, posterior, and inferior walls were significantly lower than those in normal subjects. In particular, the systolic maximal radial strain of the posterior wall in the DMD patients was the most significantly decreased (P<0.0001). Six of the DMD patients had postsystolic shortening in the inner-half, and four of the DMD patients had systolic thinning in the outer-half of the posterior wall.
Conclusions. Even if the FS is normal, the left ventricular posterior wall of DMD patients often showed an abnormal strain pattern. A segmental myocardial strain analysis might be useful for the early detection of cardiac involvement in DMD patients.