A patent foramen ovale or PFO is a defect in the wall between the two upper chambers of the heart. Most people with PFO go their whole lives without any symptoms.In fact, PFO is usually discovered only when patients undergo tests for other heart conditions. The larger the hole, the more likely symptoms are. PFOs, on the other hand, are normal before birth but may fail to close after birth. A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. Symptoms of PFO​​ Most people with a patent foramen ovale don't have symptoms. Your heartbeat feels very fast, skips beats, or flutters. This hole may let blood flow between the atria. PFO often has no symptoms.