The aetiology of cardiac dysfunction caused by sarcoid granulomatous inflammation may be difficult to clarify, and the potential of imaging methods is limited. We report on a patient who presented with acute biventricular decompensation. Pulmonary sarcoidosis was confirmed after hospitalization. Four weeks after the initiation of corticosteroid treatment, scintigraphy with indium-111-labelled antimyosin antibody Fab fragments (AMAB) revealed distinct activity accumulation in major parts of the left ventricular wall (heart-lung ratio: 1.6) 72 h following injection. There may be a role for AMAB scintigraphy in the early detection of cardiac sarcoidosis.