Abstract 14965: Cardiac MRI Derived T1 Times in Cardiomyopathy Associated with Duchenne Muscular Dystrophy are Abnormal
Introduction: Patients with Duchenne muscular dystrophy (DMD) have variable severity and age of onset of cardiomyopathy (CM). The ability to predict early CM could alter therapeutic approaches and improve morbidity and mortality. Cardiac MRI (cMRI) T1 times are an early marker of cardiac fibrosis and have not been applied to DMD CM evaluation. We hypothesized that T1 times in patients with DMD would be abnormal when compared with controls and may predict progression to CM.
Methods: A total of 24 cMRIs from 20 patients with DMD were compared with 9 cMRIs from control patients without cardiovascular disease. The look-locker sequence, obtained 10 minutes after gadolinium injection, was used to create T1 maps using MRMap, an open source software program. Multiple T1 times were obtained from each of 6 myocardial segments then averaged. Mean T1 times were compared between DMD and controls using linear regression with T1 times as a function of group, controlling for age.
Results: Mean age in years was 15.6 (range 8-23) in DMD patients and 16.9 (range 15-19) in controls. 4 patients with DMD were ambulatory; 12 patients had LVEF < 55%; 2 patients had dilated left ventricular end diastolic volumes. After adjustment for age, DMD patients had significantly lower mean T1 times compared with controls (-78.6ms, 95% CI [-134.1, -23], p=0.01) (Fig1A). Although T1 times tended to decrease with advancing age, age effects were not significant (-6.5ms for every year increase in age, 95% CI [-13.4, 0.35], p=0.06) (Fig 1B). DMD patients with abnormal late gadolinium enhancement (LGE) had significantly lower T1 times when compared to patients without abnormal LGE (-87.5ms, 95% CI [-138.8, -36.2], p=0.002).
Conclusions: Cardiac MRI derived T1 times in DMD are abnormal when compared with controls. Further study is warranted to determine if T1 times can identify DMD patients with early onset CM, predicting high risk CM phenotype. Usefulness of T1 times to monitor effect of CM therapy remains unknown.
- © 2012 by American Heart Association, Inc.