Altered Atrial Remodeling in the Muscular Dystrophies

INTRODUCTION: Muscular dystrophies (MD) are genetic disorders that cause progressive peripheral skeletal myopathies. The specific mutations lead to a cycle of muscle degeneration and regeneration in MD patients, ultimately producing progressive skeletal muscle wasting. Many of the MD patients also develop associated cardiomyopathies and in 2018 is the leading cause of death. Our group has demonstrated that MD patients have very small left ventricular (LV) masses as well as depressed LVEF. This data suggest that the mode of maladaptive cardiac remodeling may be different in MD vs NICM patients. However, it remains unknown the degree of atrial remodeling that occurs in MD patients. Therefore, the central hypothesis of this study is that atrial remodeling in MD patients is altered in comparison to non-ischemic cardiomyopathy patients. METHODS: Utilizing the UTSouthwestern Cardiomyopathy Clinic, MD and NICM patients were identified. Data was extracted from cardiac MRIs to measure left atrial (LA) volumes and function. The variables used were the LA end systolic volume (LA-ESV), LA end diastolic volume (LA-EDV), and LA ejection fraction (LAEF). These measures were normalized to the body surface area (BSA). We collected data on 78 MD patients (33 MD females, 45 MD males) and 80 NICM patients (28 NICM females, 52 NICM males). Utilizing unpaired two-sided T-test, LA data was analyzed between the matched MD and NICM patients. RESULTS: The MD and NICM patient cohorts showed significant differences in the LA structure and function. CONCLUSION: Collectively, the data suggests alternative mode of maladaptive cardiac remodeling in MD vs NICM patients. Thus, further investigation into the mechanism that leads to MD-associated cardiomyopathy may ultimately identify novel therapeutic targets for the amelioration of this disease entity.