We report the case of a 44-year-old man with dilated cardiomyocardiopathy, pulmonary hypertension and high pulmonary resistance who underwent orthotopic heart transplant. Following transplantation severe hypoxia was observed after weaning of cardiopulmonary bypass secondary to a patent foramen oval in the donor heart. This situation does not usually lead to problems in the donor, however taking into account the special hemodynamic conditions of the transplanted patient, with high pressure in the right side, an opening occurred producing a significant right-left shunt causing severe receptor hypoxia. Successful closure of the patent foramen oval was performed.