Abstract: 20 patients with congenital and rheumatic heart disease were treated with continuousper fusion on myocardium with middle hypothermia blood cardioplegia on myocardium under extracorporealcirculation. The clinical results showed higher cardial resuscitative rate, lower low cardiac output syndromerate, hemodynamic stability and much lower mortality rate than that in intermittent cold crysta1loid cardioplegia group. The result demonstrated that continuous middle hypothermia blood cardioplegia had a bettermyocardial protection effect.