Effect of deflazacort on cardiac and sternocleidomastoid muscles in Duchenne muscular dystrophy: a magnetic resonance imaging study.

OBJECTIVE: To evaluate the involvement of cardiac and sternocleidomastoid muscles by magnetic resonance imaging (MRI) measurement of T2 relaxation time and the left ventricular systolic function in patients with Duchenne muscular dystrophy (DMD) on treatment with deflazacort and compare them with DMD patients without treatment.
SUBJECTS: Seventeen patients with DMD (aged 17-22 years) on treatment with deflazacort for at least 7 years and 17 boys with DMD of younger age (12-15 years) without steroid treatment. All patients were free of cardiac or respiratory symptoms and had normal ECG and Holter monitor examination.
METHODS: T2 relaxation time of the myocardium (H), left (SCM-L) and right sternocleidomastoid (SCM-R) muscles and left ventricular systolic function were evaluated by magnetic resonance imaging (MRI) in two groups of DMD patients. Myocardial and sternocleidomastoid muscles T2 relaxation time was calculated using 16 TEs (10-85 msec) and TR at least 2000 ms and T2 maps were created.
RESULTS: DMD on deflazacort had higher T2 relaxation time values of the heart and of both sternocleidomastoid muscles (T2H median (range): 47 (41-48) vs. 33 (31-37)ms, p<0.001, T2 SCM-L median (range): 35 (30-37) vs. 23 (20-26)ms, p<0.001, T2 SCM-R median (range): 35 (32-37) vs. 23 (20-27)ms, p<0.001) and left ventricular systolic function (LVEDV median (range): 95 (75-120) vs. 90 (80-105)ml, p=0.03, LVESV median (range): 45 (38-55) vs. 47 (41-51)ml, p=0.81(NS), LVEF median (range): 53% (51-57) vs. 48% (42-51), p<0.001) compared to DMD without treatment.
CONCLUSIONS: DMD patients on deflazacort are characterized by better preservation of the T2 relaxation time of myocardium and sternocleidomastoid muscles and better LV systolic function. The duration of this beneficial effect needs to be studied prospectively.