Myocardial strain imaging for early detection of cardiac involvement in patients with Duchenne's progressive muscular dystrophy

Objective: In patients with Duchenne's progressive muscular dystrophy (DMD), myocardial fibrosis begins from the epicardial half of the left ventricular posterior wall. Myocardial strain imaging by tissue Doppler echocardiography is a new method for assessing regional myocardial function. We hypothesized that this method might be useful for the early detection of subclinical myocardial involvement in DMD patients. Methods: Myocardial radial strain of the left ventricle was measured in 25 DMD patients (age: 14.8 +/- 3.1 years) with a normal left ventricular shortening fraction and 25 age-matched healthy controls. Results: Peak systolic radial strain of the posterior wall in a short-axis view of the left ventricle was significantly lower in DMD patients compared to control subjects (P < 0.0001). In the interventricular septum, peak systolic radial strain was not significantly different between the two groups. Receiver operating characteristic curve analysis differentiated DMD patients from control patients with 92% sensitivity and 92% specificity, when the cutoff value for systolic peak strain of the posterior wall was 61%. When radial strain was measured separately for the inner and outer halves of the posterior wall, a systolic negative strain was more frequently observed in the outer half than in the inner half of the posterior wall (6/25 vs. 0/25, P < 0.05). Conclusions: Myocardial strain imaging in DMD patients was characterized by decreased peak systolic strain of the posterior wall despite normal standard echocardiographic findings. Strain measurement might be useful for early detection of subtle regional myocardial dysfunction.