Acute myocarditis with thrombus near left ventricular outflow tract.

A young woman presented with fulminant heart failure. Transthoracic echocardiography revealed severe left ventricular dysfunction with a mass adjacent to the basal anterior wall, near the left ventricular outflow tract (LVOT). The cause of the acute heart failure and mass was unclear. Transesophageal echocardiography, with contrast, and cardiac magnetic resonance imaging findings were consistent with thrombus near the LVOT. Cardiac biopsy suggested giant cell myocarditis. The patient was treated with anticoagulation, steroids, and heart failure medications with resolution of the thrombus. This case was remarkable for the location of thrombus at the base of the ventricle.