Reduced inotropic reserve is predictive of further degradation in left ventricular ejection fraction in patients with Duchenne muscular dystrophy

Abstract

AimsDuchenne muscular dystrophy (DMD), an inherited X-linked muscular disease, is associated with dilated cardiomyopathy that is responsible for death in 40% of patients. Our objective was to determine whether inotropic reserve is predictive of LV trend over time. Methods and resultsA total of 69 DMD patients (age 12.2 ± 2.3 years) were investigated. At baseline, LVEF and the presence of inotropic reserve (defined as an increase in LVEF >10% during dobutamine infusion) were investigated using radionuclide ventriculography. During follow-up (FU), LVEF was remeasured after a mean 29 ± 19 months delay. In the whole population, mean LVEF was 58 ± 8% at baseline and declined to 54 ± 11% during FU (P = 0.004). At baseline, 21 patients (30.4%) had LVEF <55% and 38 had no LV inotropic reserve. LVEF declined in the 38 patients (55.1%) without LV inotropic reserve (58 ± 8% to 52 ± 10%, P = 0.001), and not in the other patients (58 ± 8% to 57 ± 11%, P = 0.516) (P = 0.042 for trends in LVEF between groups after adjustment for age, FU duration, and baseline LVEF). Fewer patients with vs. without inotropropic reserve at baseline show a depressed LVEF <55% during follow-up (35.5% vs. 63.2%, respectively, P = 0.030). Similar findings were observed in the subgroups of patients with LVEF >45%

Is It Possible for Children in Duchenne Muscular Dystrophy to Preserve Cardiac Function with Medical Assistance?

“…Death occurs in early adulthood secondary to respiratory or cardiac failure [16]. Cardiac involvement begins as minor electrocardiographic abnormalities and evolves toward cardiomyopathy with dilatation of the cardiac chambers and depressed LV EF due to widespread fibrosis; it accounts for up to 40% of deaths [17]. Cardiac management has been challenging because the New York Heart Association classification of heart failure relies on reduced exercise tolerance, a feature that in DMD arises from skeletal muscle and cardiac disease combined.…”

“…Goudot et al reported that DMD patients without the presence of inotropic reserve (defined as an increase in LV EF >10% during dobutamine infusion) showed more significant decline of LV EF than DMD patients with the presence of inotropic reserve (p = 0.031 for difference in trend between groups). Moreover, they also reported an assessment of inotropic reserve may offer a sensitive approach for progression of cardiovascular disease in DMD children patients [17]. Based on inotropic reserve, to investigate the effect of inotropics on cardiac function in DMD cardiomyopathy, would be helpful to provide a better guideline for the treatment of DMD children.…”