Cardiac Magnetic Resonance Imaging for Myocarditis
Effective Use in Medical Decision Making
A 19-year-old man presented with new onset fatigue and dyspnea. The results of the physical examination were unremarkable. ECG was unremarkable for any ischemic changes. Echocardiography demonstrated severe global hypokinesis with an ejection fraction of 15% to 25%. Laboratory workup was remarkable for a troponin I level of 1.56, brain natriuretic peptide of 2249, white blood cell count of 32 000, C-reactive protein of 13, and creatine kinase of 156. Cardiac catheterization demonstrated no significant coronary artery disease, a pulmonary capillary wedge pressure of 3 mm Hg, and cardiac index of 2.7. Right ventricular biopsies were negative for myocarditis. Suspecting myocarditis, we performed cardiac magnetic resonance imaging (MRI), which demonstrated severe global left ventricular dysfunction (Figure, A and B, and Movie I) with focal delayed enhancement in the distal lateral wall suggestive of myocarditis (Figure, C and D). A left ventricular septal biopsy confirmed the diagnosis (Figure, I and J). We initiated immunosuppressive therapy consisting of intravenous steroids and cyclosporine. Two weeks later, repeat cardiac MRI revealed a normalized left ventricular function with an ejection fraction of 55% (Figure, G and H, and Movie II) and resolution of the lateral wall delayed enhancement (Figure, E and F, arrows). Our experience suggests that cardiac MRI can noninvasively detect myocarditis and that it may be particularly useful in deciding to proceed to left ventricular biopsy when right ventricular biopsies are negative and a high clinical suspicion for myocarditis remains.
Sources of Funding
Dr McConnell has received a research grant from GE Healthcare, Inc. Dr Yang received a grant from Stanford University and support from GE Medical Systems for magnetic resonance system research.
The online-only Data Supplement, which contains 2 movies, can be found at http://circ.ahajournals.org/cgi/content/full/113/22/e842/DC1.