My husband has a PFO, which is like the little sister to an ASD. Basically, when the baby is in utero, the blood flow inside the heart's chambers is different than after the baby is born. When the baby is in utero, oxygen comes through the umbilical cord. When the baby starts to breathe on its own, the blood gets its oxygen from the lungs, blood flow changes, and the pressure in the different chambers of the heart changes. The atrial septum does not start out as a solid wall. It starts as two pieces, one growning down from the top, and one growing up from the bottom. They are open in utero but when the blood flow and pressures change after birth, the two "flaps" are pressed together and "usually" fuse over the course of the first year of life. This is why many babies have murmurs, and why they usually go away. IF the two flaps aren't big enough to meet and fuse in the middle, the resulting hole is an ASD (atrial septal defect.) If the two flaps are big enough to meet, but for some reason don't fuse, so there is the potential for an opening, or an opening during only part of the heart beat cycle, this is a PFO (patent foramen ovale.) Basically, keep an eye on it. If the hole is so big that your baby isn't getting enough oxygen, they will want to fix it right away (failure to thrive situation.) If the hole is small, it may close on its own. If it doesn't close, you will want to have it closed surgically. Almost all of the time, this is done by doing a vein cut down in the thigh and threading a device (Amplatzer makes one, but there are several different kinds) through a catheter up into the heart, positioning the device over the hole, and deploying it into place. This is one of the most common pediatric cardiac surgeries, all the major childrens hospitals will have someone who has performed many of these procedures. Tissue grows over the device and it becomes buried within the heart wall over a relatively short time. Open heart surgery would only be considered if there were some unusual extenuating circumstance (multiple defects, size of defect, location of hole making placement of closure device extremely difficult.) I think if you had this procedure your child would be kept for overnight observation and sent home the next day. My husband has not had his repaired, but only because the protocol for PFOs is somewhat different than for ASDs. Since his opening is only open part of the time, and autopsy studies have shown that approximately 25% of the population has an undiagnosed PFO that did not interfere with a normal life, he takes an aspirin a day (prevent clots -- heart openings put you at a higher risk of stroke) and sees a cardiologist yearly for a checkup. If the asd/pfo is not repaired, a cardiologist can make sure that the heart is not working too hard in one area to compensate. If the heart muscle starts to enlarge in an asymmetrical fashion that would indicate that the opening was interfering with heart function. Well...this should get you started on your research! Best of luck.