Patent Foramen Ovale

Patent foramen ovale (PFO) is part of a group of entities known as atrial septal defects and is a remnant of normal fetal anatomy. More than half of infants have PFO at 6 months of age. Although it doesn't have a major clinical effect in neonates, it may persist into adulthood. Most adult patients with a PFO are asymptomatic; however, in some adults, PFO may result in an inter-atrial, right-to-left shunting of deoxygenated blood and the potential for shunting venous thromboembolism to the arterial circulation. These changes explain the pathophysiologic determinant of several conditions associated with PFO, including cryptogenic (having no other identifiable cause) stroke, decompression sickness, migraine, platypnea-orthodeoxia syndrome, and acute limb ischemia secondary to emboli (See Patent Foramen Ovale).