Severe hypoxemia due to shunting through a patent foramen ovale: a correctable complication of right ventricular infarction.

A patient with recent inferior myocardial infarction with right ventricular involvement developed severe hypoxemia unresponsive to 100% oxygen. Contrast two-dimensional echocardiography revealed right to left shunting through an aneurysmal fossa ovalis with a patent foramen ovale. This was confirmed by cardiac catheterization. Surgical closure of the defect was probably life-saving. This case report illustrates that right to left shunting through a foramen ovale should be considered in the differential diagnosis of hypoxemia in patients presenting with inferior myocardial infarction.