An analysis was performed on 270 open heart patients having post-operative respiratory care in the respiratory intensive care unit of Seoul National University Hospital during 1987. The analysis was done according to disease prevalence, sex, age, pump time, duration of mechanical ventilation and mortality rate. 1) The number of cases of acquired heart disease was more than that of congenital heart disease. 2) The most prevalent disease was ventricular septal defect combined with other diseases. 3) The mean age of the total patients was 36.5. The oldest age group was patients who received CABG and the youngest had a ventricular septal defect combined with other diseases. 4) The mean pump time was 93,4 minutes and it was longer in the patients with acquired heart disease than the patients with congenital heart disease. 5) The mean duration of mechanical ventilation was 68.5 hours and it was longer in the patients with acquired heart disease than those with congenital heart disease by about two times. 6) The overall mortality rate was 3.0% which was higher rate than that of the 3rd and 4th reports, and it was a higher in the patients with acquired heart disease than with congenital heart disease. The most prevalent cause of death was low cardiac output syndrome. 7) The length of mechanical ventilation time and death rate were closely related with pump time.