Duchenne Muscular Dystrophy (DMD) is caused by the absence of dystrophin in cardiac and skeletal muscle. Myocardial involvement has been traditionally diagnosed by conventional echocardiography. Our objective was to evaluate the role of Tissue Doppler (TD) in the preclinical diagnosis of myocardial involvement in DMD.
We report 15 patients, mean age 11 years (4-17 years) with DMD. All patients were studied with echocardiography with TD. Eight children had decreased functional capacity, 5 palpitations, 5 weight loss, and 4 presented with dyspnea. EKG was abnormal in 14/15 (93%). Holter showed ventricular extrasystoles in 3 patients. Conventional echocardiography showed decreased LV function in 4/15 patients (27%). LV enlargement was seen in 3 patients. LV shortening fraction was decreased in 4 patients, who had a mean SF of 23% (17-28%). Conventional Doppler showed an E/A relation <1 and enlargement of the left atrium in 1 patient, trivial mitral insufficiency in 3 and mild pulmonary hypertension in 2 patients. 11/15 patients (73%) had abnormal TD analysis in the lateral portion of the mitral ring: e´ 7 to 21 cm/s (8 patients under the normal limit for age); a´ 4 to 13 cm/s (3 patients over the normal range) and s´ 5 to 13 cm/s (4 patients under the normal range).
Conclusion: TD evaluation is more sensitive (73 vs. 27%, p<0.05) than conventional echocardiography in detecting early ventricular dysfunction in patients with DMD allowing early therapeutic intervention. TD should be part of the routine evaluation in DMD patients.