Eosinophilia associated with dobutamine allergy causes eosinophilic endomyocarditis confirmed by serial endomyocardial biopsies

We report a case of eosinophilic endomyocarditis caused by eosinophilia due to dobutamine allergy and successfully treated by a short-term and medium-dose steroid administration. Serial endomyocardial biopsies were useful for early diagnosis and evaluation of the effect of the treatment. Eosinophilic endomyocarditis due to dobutamine allergy is a rare entity; however, because of the high utilization rate of dobutamine in patients with low output heart failure, it is important to recognize that additional deterioration of cardiac function caused by eosinophilic endomyocarditis makes prognosis poor and early intervention is necessary.