<prompt> 35 year old male with history of 4 weeks of immobilization for fracture femur developed sudden onset of chest pain and hemoptysis. ECG shows s1 Q3 T3 pattern. Diagnosis?Acute myocardial infarctCOPDPulmonary embolismCor pulmonale  <response>: Ref. Grainger and Allisons Diagnostic Radiology. Page. 50 Pulmonary embolism PE usually arises from a venous thrombosis in the pelvis or legsRisk factors include any cause of immobility or hyper coagulability .Clinical features include :pleuritic chest pain ,sudden onset of breathlessness most common,hemoptysis ,dizziness ,syncope .ECG findings include sinus tachycardia most common , S1Q3T3 Most characteristic 