Atrial septal defect
From Ganfyd
| Left | Right |
| 6-10 | 0-3 |
A defect in the normal septum between the left and right atria. In normal hearts, there is no direct flow of blood between the two atria. In ASD, blood usually flows from left to right through the defect. Large ASDs are cardiologically symptomatic and repair is associated with overall clinical benefit.
A form of ASD is very common in the normal population, with a prevalance of patent foramen ovale of 30% of the population presenting for any cardiac surgery[1]. This creates immense problems in interpreting the evidence base with cardiologically asymptomatic ASD as many studies of associations (such as with stroke, paroxysmal embolism) and interventions were done before high quality transoesophageal echocardiography became routinely avaliable.
Systemic circulation embolism and migraine are related to the presence of an ASD or patent foramen ovale. Closure of the defect will stop such embolism and has reduced migraine in those whose migraine was associated with cerebral embolism. Migraine has also been precipated on closure of an ASD and this has responded to clopidogrel [2] [3].
This issue requires further evaluation but there are reports that with severe migraine with aura associated with a patent foramen ovale the net effect of closure is favourable. The preliminary results of one randomised controlled trial suggests about a 20% reduction in net migraine burden.
