Surface induced hypothermia was introduced in six cases with low cardiac output syndrome after open heart surgery to reduce oxgen consumption. The patients were consisted of two ACBG, two LV rupture after MVR, MVR with ACBG and AVR with poor LV function. Hemodynamic changes such as heart rate, mean arterial pressure, cardiac index, systemic vascular resistance, pulmonary artery wedge pressure, were measured every 3-4 hours throughout the course of hypothermia. Acid-base balance, mixed venous oxgen saturation and oxygen consumption were also monitored. Hypothermia was induced using a blanket and ice-beutels. Temperature in hypothermia was maintained at about 33°C. We are intended to increase SVO₂ up to the level of 50% and to improve anerobic condition. Hypothermia was continued for 45 hours in the shortest and 148 hours in the longest case with a mean of 78 hours. Arrythmia was not seen. Hemodynamic and acid-base balance were in significantly changed in comparison of the control values. However, SVO₂ and VO₂ changed significantly after introduction of hypothermia. They increased from 47.8±7.5% to 58.7±7.9% and reduced from 231±29.7 to 188±31.3ml O₂/min respectively. Hemodynamic condition was improved and IABP was successfully weaned in all cases. We suggest that the use of hypothermia is one of the effective modality in the management of low cardiac output syndrome after open heart surgery.

A total of 183 patients who underwent surgical repair of secundum type atrial septal defect (ASD), were divided into 5 age groups. Hemodynamic parameters, arrhythmia, and abnormality of the atrio-ventricular valve function were compared among the 5 groups. Although the pulmonary to systemic blood flow ratio was not different, the pulmonary to systemic pressure ratio was higher in the sixth decade than in the third (p<0.05) and fourth (p<0.01). Pulmonary to systemic vascular resistance ratio increased with age, although the difference was not statistically significant. The cardiothoracic ratio, atrial fibrillation and tricuspid regurgitation (TR) also increased with age. These data suggest that ASD progresses with age. There were 41 patients who showed more than grade II TR, 10 patients underwent tricuspid annuloplasty (TAP), 1 underwent tricuspid valve replacement, and the other 30 patients had no treatment of the tricuspid valve. TAP with DeVega's (6 cases) or Carpentier-ring (1) method was effective. In 30 untreated TR patients, 9 patients remained with grade II TR after closure of the defect. Because TAP is an easy and very effective procedure, TAP should have been applied to all patient with TR more severe than grade II. There were 10 patients with mitral regurgitation (MR) of more than grade II. Two patients in whom mitral valve prolapse had been detected on ultrasound cardiography (UCG) before operation underwent mitral valve plasty successfully. Although MR decreased in 6 patients after only ASD closure, two patients remained with grade II MR. We now recommend that the mitral valve should be assessed under direct vision, and intraoperative trans-esophageal echo cardiography, and also that the mitral regurgitation test as well as preoperative UCG should be performed. Because ASD is progressive with age, surgical repair should be performed before age 40.