Infiltrative Eosinophilic Myocarditis Diagnosed and Localized by Cardiac Magnetic Resonance Imaging
A 58-year-old man with a history of asthma was admitted for pneumonia and peripheral neuropathy. On admission, the patient was found to have a white blood cell count of 15.9 K/uL, with an increased eosinophil count of 2002/uL and pulmonary infiltrates seen on chest x-ray. His hospital course was complicated by hypoxia and an elevation of troponin I, which prompted a further cardiac work-up. A 2-dimensional echocardiogram revealed severe biventricular failure; however, coronary angiography was normal. Cardiac magnetic resonance imaging at 1.5T was performed using steady-state free precession imaging for function, first-pass myocardial perfusion with gadolinium-diethylenetriaminepentaacetic acid, and delayed hyperenhancement viability imaging using inversion recovery gradient echo imaging. The functional imaging confirmed the presence of a dilated global left-sided cardiomyopathic process and first-pass perfusion was normal. The delayed inversion recovery 4-chamber view is displayed in Figure 1 (inversion time=200 ms 10 minutes after IV 0.2 mmol/Kg gadolinium-diethylenetriaminepentaacetic acid). This reveals hyperenhancement of primarily the septum in a patchy and unusual distribution. Myocardial biopsy (Figure 2) shows the interstitial edema and myocyte destruction, with occasional mononuclear cells and an epithelioid response (arrowheads) to eosinophils (arrows) confirming the diagnosis of eosinophilic myocarditis. Cardiac magnetic resonance may be of value in guiding cardiac biopsy site, as interstitial infiltration may be focal.