A female mongrel dog with 14 days of ageand a weight of 600g presented severe pulmonary edema with a congestive heart failure. She was periodically examined by ECG, PCG, X-ray, and UCG studies, and at one year and three months old diagnosed as the R-L shunt PDA accompanied by the severe pulmonary hypertension. This was confirmed by autopsy after she died at two years and two months of age.