A massive proportion of the most common types of decompression illness among divers are a direct result of patent foramen ovale (PFO) or hole in the heart, Dr Stephen Glen revealed at the ScotSAC diving officers' conference.

The link between the presence of a PFO and a predisposition for decompression illness in divers is widely known*. Now an analysis of recent research has provided some startling statistics about the proportion of different decompression illnesses which are caused by PFOs.



One in four people has a PFO, but there are no proposals to routinely screen divers for the condition.

"We [the NHS] don't have the resources to do that," explained Dr Glen "and it is by no means inevitable that the presence of a PFO in a diver's heart will lead to a bend."

There are many different types and sizes of PFO; as the majority will cause no noticeable adverse symptoms there is no reason why a person with the condition would be aware of it. One illness which has been directly linked to the presence of a large PFO is migraine with 'aura' - a visual disturbance such as a shimmering blind spot or geometric patterns. A person with this condition should not consider diving without seeking expert medical advice, and if a diver develops a migraine with aura the situation should be treated as an emergency.
"If you have a post-dive aura you almost certainly have a large PFO and should consider it the equivalent of a bend," advises Dr Peter Wilmshurst who has carried out substantive research into the migraine-PFO-DCI link.


* Bubbles formed in the bloodstream during a dive are routinely filtered out in the lungs after blood returns to the right hand side of the heart. A hole in the heart wall which allows blood to pass through to the left hand side of the heart can, potentially, also allow the passage of bubbles. Bubbles in the arterial blood are more likely to become lodged in body tissues, including the brain and spine, and can result in decompression illness. Fuller explanation here

REFERENCES - DECOMPRESSION ILLNESS & PFO
Wilmshurst, Bryson et al:
Lancet 1989 (Vol 2, pages 1302-6)
Clinical Science 2000 (Vol 99, pages 65-75)
Clinical Science 2001 (Vol 100, pages 539-420)

REFERENCES - DECOMPRESSION ILLNESS, MIGRAINE WITH AURA & PFO
Wilmshurst, Bryson et al:
Lancet 2000 (Vol 356, pages 1648-51)
Clinical Science 2001 (Vol 100, pages 215-220)



Related pages
Can I be tested for a hole in the heart?
Most divers with bends diving within no dcompression limits
Decompression illness information, Hyperbaric Medicine Unit, Aberdeen



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