A 27-year-old man was admitted to the emergency department with fever and thoracic pain. In the previous 6 months, the patient lost a substantial amount of weight (12 kg). His family history was negative for cardiac disease. Electrocardiography revealed sinus rhythm, and diffuse T-wave inversion. Two-dimensional echocardiography was performed (Fig 1) and revealed normal left systolic function (ejection fraction, 60%). Laboratory tests showed elevated levels of high-sensitivity cardiac troponin (1.07 ng/mL; normal value, <0.015 ng/mL), high levels of C-reactive protein (16 mg/dL; normal range, 0-5 mg/dL), and leukocytosis with an eosinophilia level of 8710/μL (normal level, <400/μL). Parasitic and infectious diseases (Toxocara canis, strongyloides, filariasis, cysticercosis, fasciola, trichinella, echinococcosis) were excluded based on blood and fecal test results. Corticosteroid therapy was started, and the patient was dismissed. A few days later, he was readmitted to the emergency department with a headache and suddenly blurred vision. Neurologic and ophthalmologic findings were normal, and MRI of the brain was performed (Fig 2). Cardiac MRI (Fig 3) was performed 2 days later and revealed the following quantitative results: (a) left ventricular end-diastolic volume (LVDV) of 165 mL (LVDV/body surface area [BSA], 89 mL/m2; normal range, 64-100 mL/m2), left ventricular end-systolic volume (LVSV) of 80 mL (LVSV/BSA, 43 mL/m2; normal range, 17-39 mL/m2); stroke volume (SV) of 85 mL (SV/BSA, 46 mL/m2; normal range, 43-67 mL/m2); and ejection fraction of 52% and (b) right ventricular end-diastolic volume (RVDV) of 163 mL (RVDV/BSA, 88 mL/m2; normal range, 63-111 mL/m2), right ventricular end-systolic volume (RVSV) of 81 mL (RVSV/BSA, 44 mL/m2; normal range, 32-92 mL/m2); stroke volume (SV) of 82 mL (SV/BSA, 44 mL/m2; normal range, 39-71 mL/m2); and ejection fraction of 50%.