A 41-year-old woman presented with left main (LM) spontaneous coronary artery dissection (SCAD) resulting in refractory biventricular heart failure. After left and right ventricular assist device (LVAD and RVAD) placement, she remained profoundly hypoxic. Transesophageal echocardiography (TEE) demonstrated significant shunting through a patent foramen ovale (PFO). Percutaneous PFO closure was performed with a 30 mm Amplatzer Cribiform Occluder. The hypoxia resolved immediately, and the patient was subsequently weaned from RVAD, ventilator, and inotropic support. PFO closure may be necessary to prevent right-to-left shunting when left heart pressures are reduced by an LVAD.