Integrated backscatter in Becker muscular dystrophy patients with functionally normal heart: myocardial ultrasound tissue characterization study.

摘要

Becker muscular dystrophy (BMD) is an allelic X-linked recessive disorder characterized by an in frame deletion encompassing one or more exons of the dystrophin gene, with a large phenotypic spectrum, ranging between severe childhood-onset muscular disease to asymptomatic cases. Cardiac involvement (leading to cardiomyopathy and heart failure) is frequent, age-dependent, and unpredictable. Since there is no direct relationship between severity of skeletal and cardiac involvement,-cardiomyopathy frequently develops in patients with normal skeletal muscle function.Recently, we showed that ultrasound tissue characterization (UTC) of myocardium is able to detect widespread signs of cardiac involvement even in Duchenne muscular dystrophy (DMD) childrenwith normal electrocardiographs (ECGs) and left ventricular systolic function. This surprising observation lead to the hypothesis that UTC may be a useful tool in assessing early myocardial involvement in patients with other genetic diseases causing structuralchanges of myocardium. To further explore this hypothesis, we performed UTC analysis in a group of 34 BMD patients with no cardiac symptoms (ages 4 to 33 years, mean 17 +- 10 years), all with normal ECGs, left ventricular diastolic and systolic function, and segmental wall motion at baseline two-dimensional echocardiography, and in 34 healthy age-matched control subjects. The diagnosis of BMD was confirmed by muscular biopsy in all cases. None of the patients was under pharmacological treatment.