title: A broken heart: right-to-left shunt in the setting of normal cardiac pressures.
abstract: A patent foramen ovale (PFO) is a common structural cardiac variant occurring in approximately 30% of the general population. Patients are usually asymptomatic because the defect is flap-like and does not permit significant left-to-right shunting. However, pathological conditions that result in cardiac rotation or higher than normal right atrial pressures can reverse the normal left atrial to right atrial pressure gradient and cause a right-to-left shunt through a PFO. If the right-to-left shunt is persistent, systemic hypoxemia or paradoxical emboli may result. The present report describes a case of refractory hypoxemia in a critically ill patient with a PFO who had a right-to-left shunt with normal right-sided cardiac pressures.
authors.affiliation: Division of Cardiology, Faculty of Medicine, University of Western Ontario, London Health Sciences Centre University Hospital.
authors.forename: Natalie
authors.initials: N
authors.lastname: Gomperts
authors.forename: Robert
authors.initials: R
authors.lastname: Fowler
authors.forename: Eric
authors.initials: E
authors.lastname: Horlick
authors.forename: Peter
authors.initials: P
authors.lastname: McLaughlin
mesh_terms: D004452:Echocardiography; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D008875:Middle Aged; D017725:Ventricular Pressure