ABSTRACT
Topical cardiac hypothermia has unequivocal preservation effects during ischemia, but it has some disadvantages. Topical cooling, especially with ice slush, can injure the phrenic nerve, disturb the equal distribution of the cardioplegic solution due to coronary artery spasm and damage the epicardium. It is easy to prevent cooling injury without topical hypothermia, but the myocardial oxygen demands are increased. In order to supply the myocardium with oxygen for the increased oxygen demands during ischemia, isolated rat hearts were immersed in perfluorochemicals (PFC) which have excellent transportation of oxygen. The effects of immersion in PFC during mild hypothermic ischemia (at 20°C without cardioplegia and at 30°C cardioplegic arrest) on the cardiac function on reperfusion were evaluated. Under 20°C hypothermic ischemia without cardioplegia, cardiac beating was maintained for 20±4 minutes in the hearts were immersed in PFC, and for 10±2 minutes in the hearts that were not immersed in any solution. In the recovery of cardiac function (LVDP and LV<sub>max</sub> d<i>p</i>/d<i>t</i>) after mild hypothermic (30°C) cardioplegic arrest, the hearts immersed in PFC showed better results than hearts that were not immersed.