A 60-year-old woman with biopsy-proven cardiac sarcoidosis status post implantable cardioverter defibrillator placement presented with periodic dizziness and dyspnea on exertion. Myocardial perfusion scan demonstrated a moderate sized, fixed perfusion defect along the mid to proximal anteroseptal wall of the left ventricle, with better perfusion on stress images. FDG-PET/CT demonstrated corresponding focal FDG avidity of the mid to proximal anteroseptal wall, suggestive of active cardiac sarcoidosis. Because of severe side effects, mycophenolate mofetil was discontinued, and the patient received low-dose steroid therapy. At 7-month follow-up FDG PET/CT, there was increased FDG avidity in the same regions, indicating worsening cardiac sarcoidosis.