A Case Series of Biopsy-Proven Eosinophilic Myocarditis at a Tertiary Care Center

Background There is limited published literature on acute eosinophilic myocarditis (EM), a rare form of acute myocarditis, wherein eosinophils invade the myocardium with wide-ranging clinical sequalae. We aim to describe our experience in the largest contemporary case series of histologically-proven EM. Methods Two authors independently reviewed the surgical pathology and autopsy databases for acute EM (01/2009 to 12/2017). Only patients with endomyocardial biopsy/autopsy and clinical course consistent with acute EM were included. We abstracted demographic data, comorbidities, clinical diagnostics, and clinical outcomes. Results Seven patients had acute EM (Table). The average age was 53-years and five subjects were women. The most common etiology of EM was idiopathic. Five patients had peripheral eosinophilia. Three patients had elevated pulmonary capillary wedge pressure and three patients had reduced cardiac output. Six patients were treated with steroids, four of whom received IV pulse dosed steroids. Two patients required intra-aortic balloon pump support, one of whom subsequently underwent durable left ventricular assist device implantation. Two patients died during index hospitalization, one of septic shock and one of refractory ventricular tachycardia. Conclusion The etiologies, clinical presentation, and course of acute EM varied widely. Prompt diagnosis, treatment with immunosuppression, and circulatory support may reduce cardiovascular mortality in this population.