Detection of Progressive Cardiac Dysfunction by Serial Evaluation of Circumferential Strain in Patients With Duchenne Muscular Dystrophy

The present study evaluated progressive cardiac dysfunction using serial circumferential strain (ε_cc) measurements in patients with Duchenne muscular dystrophy (DMD). DMD is characterized by progressive cardiac dysfunction and myocardial fibrosis late in the disease process. We hypothesized that serial ε_cc changes could be detected in individual patients with DMD during a time when the left ventricular ejection fraction (EF) changes are insignificant. Cardiac magnetic resonance imaging data from patients with DMD were evaluated. The left ventricular EF was calculated from steady-state free precession cine images and the composite ε_cc measurement from tagged cine images. The serial ε_cc and EF values for each patient were analyzed using the Wilcoxon sign rank test. Data from 51 patients with DMD (2 studies per patient, mean age at the initial study 11.8 ± 3.5 years, range 7.4 to 25.4) were analyzed, with a mean interval between cardiac magnetic resonance studies of 15.6 ± 6.0 months (range 6.2 to 28.1). In the interval between studies, the ε_cc had decreased in all patients with DMD. The average decrease was 1.8 ± 1.3 (p <0.001). However, the EF had decreased in 33 of the 51 patients and had increased in 18 of the 51 patients. On average, the EF decreased by 2.9 ± 8.57% (p = NS). In conclusion, in patients with DMD, ε_cc abnormalities indicate progression within a relatively short period when the EF changes were not significant. Serial ε_cc measurements might provide reliable monitoring of the progression of DMD-associated cardiac dysfunction before overt heart failure develops, because it is more sensitive than the EF.