Patent foramen ovale with right to left shunt as a cause of hypoxia.

Patent foramen ovale with right to left shunt as a cause of hypoxia without Eisenmengers physiology or with only moderately pulmonary artery pressures is an uncommon presentation. Initial diagnosis via transesophageal echocardiography requires detection of a shunt with either color Doppler or agitated saline contrast with or without Valsalva maneuver. This rare but diagnosable case presented was simply corrected with placement of a CardioSEAL device. Causes of right to left shunt without elevated pulmonary artery pressures are discussed.