Longitudinal changes in cardiac function, volumes and fibrosis in a prospective cohort of female Duchenne and Becker muscular dystrophy carriers.

BACKGROUND

Female Duchenne and Becker muscular dystrophy carriers (MDC) have heterozygous dystrophin mutations with an unclear disease phenotype. While cardiomyopathy is the leading cause of death in affected males, the natural history of MDC is not known. We describe changes in ventricular volumes, function, and fibrosis by late‑gadolinium enhancement (LGE) using cardiac MRI (CMR) in a prospective cohort of MDC and non-carrier females.

METHODS

75 genetically-confirmed MDC and 22 non-carriers underwent CMR at three annual visits.

RESULTS

Follow-up included 85 (65 MDC, 20 non-carriers) and 62 (46 MDC, 16 non-carriers) subjects who underwent CMR at visits 2 and 3, respectively. Mean ejection fraction and LV volumes remained within normal limits for both cohorts and did not show evidence of different slope of change. 36/75 MDC and 1/22 non-carriers had LGE at visit 1. In those with LGE positivity at visit 1, 13/28 progressed extent of LGE within 2 years. Non-progressors and progressors had similar characteristics of age, cardiac medications and LV function and volume.

CONCLUSION

Longitudinal changes in cardiac volumes and function in MDC are similar to non-carrier controls. Subjects free of LGE at visit 1 remained free of LGE through the study period. In subjects with LGE positivity at first CMR, half progressed in LGE extent. Current CMR screening guidelines for MDC of 3-5 years appears appropriate for those without fibrosis and with normal LVEF and LV volumes. For those with fibrosis on imaging, surveillance intervals should be shorter based on findings of progression in a 2 year period.