Abstract 16962: Maladaptive Atrial Remodeling in Muscular Dystrophy

Abstract

Background: Muscular dystrophies (MD) are genetic disorders that cause progressive peripheral skeletal myopathies. The majority of MD patients will develop atrial and ventricular arrhythmias and/or an associated cardiomyopathy with a high degree of morbidity and mortality. However, it remains unknown the degree of atrial remodeling that may also occur in MD patients. We hypothesize maladaptive atrial remodeling occurs in MD patients. Methods: Utilizing the UT Southwestern Cardiomyopathy Clinic, MD [total: 79 patients (34 females, 45 males)] and non-ischemic cardiomyopathy (NICM) [total: 81 patients (29 females, 52 males)] patients were identified who underwent a cardiac MRI (cMRI) between 2011 and 2015. A matched, healthy control cohort from the Dallas Heart Study (DHS) [total: 101 patients (40 females, 61 males)] were identified. Most MD patients had Duchenne/Becker MD, Limb-Girdle MD or myotonic MD. Two blinded, independent readers made volumetric measurements from cMRIs to assess right atrial (RA) and left atrial (LA) dimensions with low inter-reader variability. A third independent investigator analyzed the RA and LA data with aggregate data presented in the Table. The statistical significance of the data (p<0.05) was assessed by performing an unpaired two-tailed Student’s t-test and a one-way analysis of variance (ANOVA) between groups with a Bonferroni’s post-test analysis. Results: Analysis of the cMRI data revealed significant differences in both the structure and function of the RA and the LA between MD and NICM patients. In addition, the data revealed significant differences in the LA but not the RA emptying fraction in MD patients as compared to the DHS patients. Conclusion: Collectively, the data suggests MD patients develop significant maladaptive remodeling of the LA but not the RA, predisposing these patients to atrial arrhythmias. Investigation into differences in atrial remodeling as a function of gender and the type of MD need to be explored.