Prognostic Improvement of Acute Necrotizing Eosinophilic Myocarditis (ANEM) Through a Rapid Pathological Diagnosis and Appropriate Therapy.

We present the case of a patient with acute necrotizing eosinophilic myocarditis (ANEM) who rapidly recovered after receiving high-dose corticosteroid therapy. A previously healthy 29-year-old woman presented to our hospital with abdominal pain, nausea, and fever that had lasted for two days. Her clinical condition progressively declined and she ultimately presented with cardiogenic shock due to fulminant heart failure and atrioventricular dissociation due to sinus bradycardia, which required inotropic and ventilatory support. Endomyocardial biopsy results were consistent with ANEM. High-dose corticosteroids were promptly initiated, and her cardiac function rapidly improved, with almost complete cardiac recovery one week later. She survived with completely normalized left ventricular systolic and diastolic function after high-dose corticosteroid therapy. The prompt and definite pathological diagnosis based on endomyocardial biopsy in the acute phase might have been instrumental in improving the outcome.