IT QUACKS LIKE A DUCK, BUT IT ISNT A DUCK. S. Dubey 1 , B. Marinelli 1 ; 1 Hennepin County Medical Center, Minneapolis, MN LEARNING OBJECTIVES: 1) To recognize precordial changes on EKG as a manifestation of massive pulmonary embolism 2) To emphasize the importance of screening for major alternative diagnoses in patients who present with apparent acute coronary syndromes CASE INFORMATION: A 44-year-old man, with history of coronary stent placement in the left anterior descending artery five months previously, presented with sudden chest pain and dyspnea. Relevant past medical history included a motor vehicle accident several months ago, which resulted in multiple lower extremity procedures and infections leading to reduced ambulation. EKG on admission was significant for precordial T wave inversion, and preliminary trans thoracic echocardiogram done in the emergency department showed normal left ventricular function. Considering stent closure, a coronary angiogram was done which showed patent coronaries. At that time, the formal reading from the already done echo was obtained and showed right ventricular enlargement and reduced right ventricular function. Immediate pulmonary angiogram was done and revealed extensive thrombus in the left pulmonary arterial system. Thrombolysis was initiated with t-PA. DISCUSSION: This is an example of acute pulmonary embolus very convincingly masquerading as coronary stent closure. An important clue, namely, reduced ambulation due to recent leg injuries, lay hidden in the past medical history. Precordial T wave inversions on EKG in the setting of pulmonary embolism, has been well described in medical literature. Various theories, including true coronary insufficiency and catecholamine mediated global T wave inversions have been proposed. The presence of such T wave inversions correlates with increased severity of pulmonary embolism, and resolution over a few days correlates with improved prognosis. Treatment includes anticoagulation with or without thrombolysis. Such EKG changes warrant at least a detailed history and physical exam focusing on deep vein thrombosis and pulmonary embolism risk factors.