田中 秀和

Hidekazu TANAKA

神戸大学大学院循環器内科学分野

Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine

キーワード :

Duchenne muscular dystrophy（DMD）is an X-linked recessive disease affecting approximately 1 in 3,500 live-born male children worldwide. DMD is caused by mutations in the dystrophin gene that result in marked reduction or absence of the sarcolemnal protein dystrophin. Death of DMD patients is usually due to cardiac or respiratory failure, and distinctive pathologic findings for these patients have been noted. The incidence of cardiac complications in DMD patients increases with age, affecting 30％of patients by the age of 14 years, 50％by the age of 18，and all older patients. Overt symptoms due to heart failure resulting from severe limitations of daily activities occur in about 30％of cases. Since subclinical left ventricular（LV）myocardial dysfunction may develop and progress early in life, the early detection of this abnormality in DMD patients when their LV ejection fraction（LVEF）remains preserved is important because medical treatment can be administered earlier, and is therefore vital for prevention of the development of myocardial fibrosis. Fibrotic changes, however, do not always occur homogeneously in the heart and cardiac fibrosis in DMD patients begins in the outer half of the myocardium, especially in the LV posterior wall. Moreover, early detection of subclinical LV dysfunction in DMD patients with preserved LVEF can be challenging. We previously reported in a study of 82 DMD patients with preserved LVEF that the transmural myocardial strain profile（TMSP）with a notch at rest functioned as a robust predictor of the presence of LV posterior wall motion abnormality detected at 1-year follow-up1. In addition, we recently showed that combining the passive leg-lifting maneuver with assessment of TMSP was more effective for predicting new development of LV posterior wall motion abnormality for 95 DMD patients with preserved LVEF 2.
This lecture reviews the utility of echocardiographic assessment in DMD patients, and its potential clinical applications for detecting subclinical LV dysfunction.
References
1 Yamamoto T, Tanaka H et al. Am J Cardiol. 2013;111:902-907.
2 Yamamoto T, Tanaka H et al. J Cardiol. 2015;66:212-7.