Purpose or Case Report: Duchenne muscular dystrophy (DMD) is a myopathy with a natural history of progressive cardiomyopathy and vasogenic edema, fatty infiltration, and myocardial fibrosis. We recently identified a group of patients with DMD who presented with acute onset of chest pain (ACP), troponin leak (TL), and new late gadolinium enhancement (LGE), similar in presentation to acute viral myocarditis (AM). It is unclear if these patients have suffered an episode of AM or if this is a different disease process. Given the presumed acute myocardial necrosis in both processes, we hypothesize that native T1 and T2 values would be elevated in AM and DMD patients with ACP compared to asymptomatic DMD patients.
Methods & Materials: This was a retrospective study of three groups: Group 1: DMD, LV ejection fraction (LVEF) > 55%, and no LGE; Group 2: DMD presenting with ACP, TL, and new LGE; Group 3: clinical diagnosis of AM. All patients from January 2016 to June 2018 with native T1 and T2 mapping performed during a clinically indicated cardiac MRI study were included. T1 and T2 mapping was performed at a single mid-ventricular short axis slice. The slice was divided into a septal, anterior, and inferior region. All images were post-processed by a single observer.
Results: LVEF was lower in the Group 3 (p <0.05) compared to Group 1, with no difference between Group 2 and 3 (p = 0.99). Native T1 values were elevated in Group 2 (p < 0.01) and Group 3 (p = 0.02) compared to Group 1 with no difference between Group 2 and 3 (p = 0.41). However when comparing T2 values for Group 1 and Group 2, this did not reach statistical significance (p=0.72) despite their similar age. T2 values for Group 3 were statistically higher for all segments when compared to Group 1 (p < 0.01) and approached statistical significance when compared to Group 2 (p = 0.07). Regional differences were identified in the native T1 maps, particularly in the inferior segment.
Conclusions: Patients with DMD who present with ACP, TL, and new LGE have increased T1 values compared to asymptomatic DMD patients, and similar to patients with AM. Increased signal is particularly noted in the inferior and anterior segments. However their T2 values are similar to the asymptomatic DMD patients and lower than AM patients. Although the presentation and clinical course of the DMD patients with ACP and TL has many similarities to AM, the T2 values suggest a lack of significant myocardial edema. This may represent a unique and unusual disease process in the natural history of DMD.