Idiopathic hypereosinophilic syndrome presenting as severe Loeffler's endocarditis.

Loeffler ’s endocarditis, also known as Loeffler ’s endomyocardial disease, was first described by Wilhelm Loeffler in a patient with progressive heart failure due to eosinophilic infiltration of the endomyocardium, which was found to be secondary to peripheral eosinophilia1. It appears to be a subset of hypereosinophilic syndrome (HES), in which the heart is predominantly involved, characterized by fibrous thickening of the endocardium of one or both ventricles leading to apical obliteration and restrictive pathophysiology resulting in multiple cardiovascular complications.