Right hemidiaphragmatic elevation with a right-to-left interatrial shunt through a patent foramen ovale: a case report and literature review.

A right-to-left shunt (RLS) is an uncommon complication of a patent foramen ovale (PFO) that may cause hypoxemia from venous admixture and ischemic complications from paradoxic embolization. This report presents the third described patient whose RLS through a PFO and profound hypoxemia developed in association with right hemidiaphragm dysfunction (but without a pressure gradient driving the right-to-left flow). In addition to extending the available experience with this unusual clinical event, we report on the successful closure of the PFO by a catheter-deployed double-umbrella device, after the positioning of which the patient's oxygenation normalized.