Recently, a woman with Turner's syndrome and severe mitral insufficiency was operated upon in our department. After releasing the cross clamp, she went into overt biventricular failure and required ECMO support. A myocardial protection problem during x-clamp was ruled out. She underwent coronary angiography immediately postoperatively demonstrating severe spasm of all major coronary arteries reversible to intracoronary nitroglycerin. At present, coronary vasospasm seems to have caused this pump failure.