The authors report a case of localised compression of the right atrium due to a loculated intrapericardial haematoma after open heart surgery. The patient suddenly developed signs of superior vena caval obstruction during the third postoperative week. The diagnosis was made by 2D echocardiography and superior vena cavography. The authors review the literature and discuss the main clinical features of localised cardiac tamponade, underlying the value of 2D echocardiography in the postoperative management of cardiac surgical patients.