Cardiac herniation through mediastinotomy incision

A 43-year-old man was admitted to the emergency department after a cardiac arrest of unknown etiology. The patient's medical history was unremarkable except for surgery to remove a mediastinal lipoma two years earlier. In the intensive care unit, he was observed to have a mass bulging from the left chest wall. Echocardiography showed cardiac herniation through the chest wall, which was confirmed by thoracic computed tomographic scan.