Hi Externet,
Let's open on a positive note--PFO is not necessarily an absolute contraindication to recreational scuba. In fact, with repair it rarely is.
The following discussion of PFO and its implications for scuba, which is considerably more extensive than the information on DAN's website or with which they will otherwise provide you, may be educational. It's an updated and expanded piece based on an item appearing in my "Ask RSD" column in "Rodale's Scuba Diving":
"Scuba and Patent Foramen Ovale (PFO)
PFO, a type of atrial septal defect, is an abnormal opening between the right and left upper chambers of the heart (Basic Heart Anatomy---->
http://texasheart.org/HIC/Anatomy/anatomy2.cfm).
It is normal for blood to flow through a small opening between these two chambers during fetal development when the lungs are inoperative and blood is oxygenated by the mother. At the moment of birth, however, changes in chamber pressures cause this membranous opening to close, shunting blood to the now functioning lungs.
While usually permanently sealed by very early in life, closure does not always occur; about one in every four persons has an incomplete closure of varying size. Without complete closure, blood can flow from the right to the left side of the heart without passing through the lungs.
Large and persistent PFO and other right-to-left shunts are associated with poor exercise tolerance, migraine headache (particularly migraine with aura) and the sudden loss of blood circulation to areas of the brain (ischemic stroke).
Because the left side of the heart is the "high pressure side," the majority of otherwise healthy persons with PFO, many with only small openings, are unaware they have the condition. However, given a shift in the normal pressure gradient between these two chambers of the heart, blood can flow in the wrong direction.
Of significance to divers with PFO is the increase in right chamber pressure which occurs with common equalization techniques like the Valsalva maneuver. Under this condition, inert gas bubbles that form in the venous bloodstream during decompression can pass directly into the arteries without the filtering action of the lungs.
Divers with PFO can develop decompression illness (DCI) manifestations ranging from relatively harmless skin rashes to serious neurological problems such as unconsciousness and paralysis.
Moreover, bubbles passing into the brain can obstruct blood vessels, resulting in lesions of various size. Studies of high frequency divers have documented an increased likelihood of large and/or multiple brain lesions, and shown that a high percentage of divers who had otherwise unexplained incidents of DCI turned out to have PFO. In addition, the risk of severe DCI appears to be about three to five times greater in those with PFO as compared to the general diving population; the relationship is much weaker for mild cases.
Despite research findings of increased risk of DCI in the presence PFO, the overall risk in the general population of divers still is very low. Most dive medicine experts do not recommend an echocardiogram as a routine procedure in healthy recreational divers. However, evaluation for PFO should seriously be considered given otherwise unexplained incidents of DCI, especially neurological DCI. A recent study showed an increase in the prevalence and size of PFO in divers followed over a 7 year span, suggesting a possible increasing risk for decompression sickness in certain divers over time.
At present, the gold standard for detecting the presence and nature of a PFO is transesophageal echocardiography (TEE) with bubble contrast (but see #1 below for non-invasive alternative techniques). This procedure allows bubbles passing from the right to the left to side of the heart to be observed. Even a relatively small number of bubbles is a matter of concern. The basic procedure is described here----> Echocardiography
http://en.wikipedia.org/wiki/Echocardiography.
If repair is indicated, the procedure selected depends upon a number of factors including the size of the opening. There are several approaches, including suturing of the defect or placing a tissue patch over it, although preferred where possible is the non-surgical placement of a blocking device such as the Amplatzer Septal Occluder described here----> Amplatzer
http://www.fda.gov/cdrh/mda/docs/p000039.html. The placement of such occluding devices has a high rate of success and low rate of complications.
At some point following the repair TEE with bubble contrast likely will be repeated. With these findings and other information regarding fitness to dive, the diver and his physician can decide on the best course of action. Given an uncomplicated and successful closure in an otherwise healthy and fit individual, return to diving typically can be expected within 6-12 weeks. ©Doc Vikingo 2005"
#1 Should All Divers be Screened for PFO? ---->
http://tenfootstop.blogspot.com/2006/07/should-all-divers-be-screened-for-pfo.html
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice with you or any other individual and should not be construed as such.
Helpful?
Regards,
DocVikingo
