The following info was found on the HomePage of the National Stroke Association's website (www.stroke.org) :

Patent Foramen Ovale (PFO) and Stroke

"Have you or someone you know had a stroke or TIA (transient ischemic attack or mini-stroke) "out of the blue" with no obvious risk factors? Did doctors check to see if the stroke or TIA may have been caused by a "hole" in the heart called a patent foramen ovale (PFO)?"

"About one in five Americans has a PFO. Many don't know it until a medical condition like a stroke or TIA occurs. PFOs often have no symptoms but they may increase your risk for stroke and TIA. Many PFO-related stroke are called cryptogenic, meaning they have no apparent cause."

Please visit the NSA website to see additional information this topic and other topics related to stroke.