The diagnosis of superior vena cava syndrome is always challenging, even more so when it happens intraoperatively. A novel transgastric-transesophageal projection allows for the visualisation of caval flow acceleration, critical in leading to rapid diagnosis and quick reaction in the operative setting. We present the case of a patient who underwent successful mitral valve reconstruction and left atrial appendage closure via median sternotomy on cardiopulmonary bypass and intraoperatively developed iatrogenic superior vena cava syndrome. This novel transgastric-transesophageal echocardiographic projection proved crucial in identifying it and immediate intraoperative management.