New insights about the risks from a “hole” in the heart

About 25% of people have a common heart variant called a patent foramen ovale (PFO), a flaplike opening between the heart’s upper chambers. In people with the condition, venous blood can leak across the heart from the right atrium to the left atrium, bypassing the lungs. If that blood contains a clot, it can travel directly to the arteries that send blood throughout the body. A stroke can occur if that clot lodges in an artery supplying the brain. In people prone to blood clots, a PFO raises the risk of stroke and dementia.