People with migraine are more likely to have a patent foramen ovale (PFO)—which is an opening or hole between the two small chambers in the heart-than those who do not have migraine. Conversely, patients with stroke and PFO are more likely to have migraine, especially the form of migraine called migraine with aura. This association led a group of researchers to look back at records of 162 patients who underwent closure of the PFO to prevent recurrent stroke or warning of stroke. They published their results in the February 2005 issue of the Journal of American College of Cardiology. Of the patients studied, 35 percent had migraine regularly; more than half of these had aura. After the surgery, over half of these patients no longer had migraine. Of the remaining group, 14 percent reported a significant reduction and 80 percent had fewer migraines. The researchers concluded that closure of PFO reduces the frequency of migraine attacks.

Another study reported in February 2005 issue of the Journal of American College of Cardiology covered a similar topic. This study looked at patients who either had PFO and a stroke or an atrial septal defect (ASD), which is also an opening between the two upper chambers of the heart. It causes blood to go from one upper chamber to another in addition to going the normal way from the upper to the lower chamber. Generally, a large ASD causes significant blood to go into the right upper (atrium) and the right lower (ventricle) heart chambers leading to enlargement of these chambers. About 42 percent of these patients suffer from migraine. Again, the researchers looked at whether closing the shunt would result in fewer migraines. The study looked at 89 patients after treatment. Of them, migraine disappeared completely in 75 percent of the group after three months. Of the remaining group, 40 percent had significant improvement.