In this case report we present two patients with unusual manifestations of eosinophilic endomyocarditis: A 69-year-old patient with a history of heart failure and ventricular fibrillation and a 16-year-old woman with ventricular fibrillation and an ECG indicating acute myocardial infarction had both normal blood eosinophil counts at the onset of symptoms. The absence of hypereosinophilia, therefore, does not exclude the presence of eosinophilic organ infiltration. Endomyocardial biopsy may be the only diagnostic procedure to identify necrotic eosinophilic endomyocarditis in patients with unexplained heart failure or ventricular fibrillation.