We present the case of a patient with pericardial tamponade caused by a rare complication of atherosclerosis. An eightyyear- old male suffered a witnessed cardiac arrest due to pulseless electrical activity (PEA). Transthoracic echocardiography showed a pericardial effusion of 1.5 to 2 cm. Emergency subcostal pericardiocentesis drained approximately 15 ml of sanquinolent fluid. Subsequent CT scan of the thorax showed a penetrating atherosclerotic ulcer (PAU) of the proximal ascending aorta with signs of active bleeding into the pericardium and right pleural cavity. The patient was diagnosed with a pericardial tamponade and haematothorax due to a perforated PAU of the ascending aorta, resulting in PEA. Although a PAU of the descending aorta and distal aortic arch can be treated by endovascular repair (EVAR), open thoracic surgery remains the treatment of choice for lesions located in the ascending aorta or proximal mid-aortic arch. © 2010, Nederlandse Vereniging voor Intensive Care.