Congenital heart conditions: the 'headache' of assessing a link between PFO and migraine.

The relationship between patent foramen ovale and migraine is a hotly debated issue. Conflicting data on the association or independence of these conditions have been reported by various study groups around the world. Now, a large-scale case-control study has shown no association between the two entities; however, there were a number of methodological flaws in this study and we are unlikely to see the end of the controversy in the near future.