A 22 year old naval serviceman presented with a six day history of retrosternal chest pain and ST segment elevation on the ECG. The chest pain was not typically ischaemic, nor did the patient have risk factors for coronary disease. The admission ECG (panel A) showed sinus bradycardia, right axis deviation, incomplete right bundle branch block, clockwise rotation, and ST segment elevation in the inferolateral leads. Clinical examination was unremarkable and bedside echocardiography revealed normal left ventricular size and function. A decision was therefore made not to proceed to coronary angiography and the patient was admitted to the ward.

Initial laboratory investigations revealed no evidence of an inflammatory process and markers of myocardial necrosis were negative. The opinion of a radiologist was sought as the plain chest radiograph showed leftward displacement of the cardiac silhouette with a rim of lucency between the inferior border of the heart and the left hemidiaphragm (panel B), raising the suspicion of congenital absence of the pericardium. This diagnosis was subsequently confirmed by ECG gated computed tomographic (CT) scan of the heart with intravenous contrast (panel C), that demonstrated complete absence of the pericardium around the heart with the coronary arteries lying freely within the epicardial fat. Coronary artery patency was confirmed at angiography.

Complete congenital absence of the pericardium is rare but well described in the literature. However, ST segment elevation has not been reported previously. It should thus be considered in young patients presenting with chest pain. The chest radiograph is suggestive but confirmation usually requires CT or magnetic resonance imaging.