Though acute pulmonary thromboembolism is usually managed medically with the use of thrombolytics or anticoagulants, an emergent life-saving surgery would be required. In a case of acute pulmonary thromboembolism with acute severe right heart failure and deferment of it could result in fatal outcomes in a short time. In addition, the mortality is raised considerably if it is combined with right heart thrombi. Despite paradoxical thromboembolism via patent foramen ovale was reported, few report might be presented, in which showed the thrombus in right atrium has traversed atrial septal defect into left atrium and left ventricle like this case as the evidence of paradoxical thromboembolism. We report a case of acute pulmonary thromboembolism with acute right heart failure arising from deep vein thrombosis, developed immediately after low anterior resection for colon cancer in a 63-year-old male, who was managed successfully by emergent thromboembolectomy with cardiopulmonary bypass.