[Intraoperative ST-T changes resembling myocardial ischemia due to accidental myocardial cooling]

During the mitral valve replacement on a 48-year-old male with mitral valve stenosis, ST-T changes (ST elevation and T inversion) suddenly appeared just before the start of cardiopulmonary bypass. Myocardial ischemia was suspected before we noticed the cardioplegic solution (about 10 degrees C) had been dripping on the surface of the right ventricle by mistake for about five minutes. After pouring warm saline over the myocardial surface, the EKG returned to normal within ten minutes. In this case, there appeared the elevation of the J point which is characteristic of profound hypothermia and is easily mistaken as myocardial ischemia because of ST segment elevation. It is very important to observe even a trivial intraoperative action which is not directly related with the operative procedure.