A 72-yr-old man was electively admitted for cardiac revascularisation 6 weeks after an inaugural inferior infarct. His physical examination and laboratory test were unremarkable. According to his coronarography the patient was programmed for an off pump coronary artery bypass. During surgery the heart was found to be completely herniated in the left chest, passing on the posterior aspect of the phrenic nerve. Symptomatology and complications of congenital pericardial defects are reviewed.