The authors report the case of an acquired left ventricle-right atrial communication after open chest trauma. The initial clinical presentation was a haemothorax and haemopericardium responding well to emergency surgical drainage. Secondarily, a systolic murmur suggesting a ventricular septal defect and signs of right heart failure were observed. Colour Doppler echocardiography led to the diagnosis of a left ventricle-right atrial communication associated with tricuspid regurgitation with dilatation of the right heart chambers and pulmonary hypertension. At surgery, a defect in the membranous interventricular septum was confirmed with rupture of the septal tricuspid leaflet causing tricuspid regurgitation. The surgeon closed the defect with a patch and performed a De Vega tricuspid valvuloplasty. The postoperative outcome was uneventful.