Refractory hypoxemia as a complication of right ventricular infarction is rare. A 74-year-old man developed persistent hypoxemia due to right-to-left interatrial shunting through a patent foramen ovale during the acute phase of right ventricular infarction. Short-term percutaneous transvenous closure of the patent foramen ovale with a large balloon occlusion catheter was life-saving.