Abstract 19421: Cardiovascular Magnetic Resonance Imaging and Spectroscopy Detects Myocardial Fibrosis and Lipidosis in Patients with Dystrophinopathies, Even in the Presence of Normal Left Ventricular Ejection Fraction
Background: Dystrophinopathies (Becker-BMD and Duchenne muscular dystrophies-DMD) are X-linked abnormalities of dystrophin associated with a high rate of cardiomyopathy.
Hypothesis: Therefore this prospective CMR study assessed cardiac function, strain, fibrosis, myocardial energetics and myocardial lipids in patients with inherited dystrophinopathy and normal left ventricular function.
Methods and Results: Patients with BMD or DMD (n=14) (age 39±12yrs) and normal left ventricular ejection fraction (LVEF 65±4%), and 14 matched volunteers (age 39±15yrs; LVEF 69±5%) were scanned at 3T. 31P MRS (n=13/14) and 1H MRS (n=6/14) were performed, interrogating the mid-ventricular septum. 1H spectra results were compared to 22 healthy volunteers (Figure 1). The cardiac PCr/ATP ratio in dystrophinopathy patients was significantly lower than the age matched controls (Figure 2, Dystrophinopathy 1.51±0.21 vs. normals 2.07±0.28; p<0.0001). Circumferential strain was impaired in patients with dystrophinopathy (13.3±3.4) compared to healthy volunteers (18.6±1.9). In dystrophinopathy, areas of late gadolinium enhancement (fibrosis) were 16±9 % of total LV mass. 1H spectra (n=6/14) revealed striking myocardial lipidosis (Figure 2, Dystrophinopathy 1.8±0.5% vs. Normals 0.5±0.2%, P<0.001, lipid % = 100xlipid/water amplitude).
Conclusion: Dystrophinopathy induces myocardial fibrosis, impaired strain and abnormal energetics even in the presence of normal left ventricular function. Myocardial lipidosis suggests impaired fat utilisation and also implicates lipotoxicity as a potential disease mechanism.
- © 2010 by American Heart Association, Inc.