Patent foramen ovale (PTO) is an opening between the two upper chambers of the heart. Its size varies, and while most are small, not all are. In some folks its large enough to cause exercise intolerance, difficulty breathing & recurrent respiratory infections.
As regards estimates of prevalence, commonly cited figures are more like 20-30% than 30-40%.
Repair by cauterization with a probe inserted through the femoral artery often is no longer considered the technique of choice. If the PFO is of the appropriate location & size, a tube can be advanced up the femoral artery and one of several types of little double umbrella-like devices inserted. These cover each side of the hole and close it. Over time, heart tissue grows over the implant, becoming part of the heart. However, some PFOs require surgical closure, either with sutures alone or a tissue patch.
BTW, you asked about it healing spontaneously. To the best of admittedly limited knowledge, if it has not closed by adulthood, it is not going to close by itself.
Here is a brief & simple piece that you might find informative. It's an edited version from my "Ask RSD" column in the Apr '00 issue of "Rodale's Scuba Diving" magazine:
"1. What is patent foramen ovale (PFO)?
PFO is an abnormal opening between the right and left upper chambers of the heart.
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 the 3rd month of life, this does not always occur; about 25%-30% of people have 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, causing a decrease in the amount of oxygen reaching the body. This may limit exercise tolerance, although generally is a problem only when the opening is quite large. The majority of otherwise healthy persons with PFO, many with only small openings, are entirely unaware they have the condition. It typically requires no treatment in the adult.
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, nitrogen bubbles that can form in the venous bloodstream during decompression may 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 vertigo or paralysis.
Studies have shown that a high percentage of divers who had otherwise unexplained incidents of DCI, especially Type II DCS, turned out to have PFO. In addition, the risk of severe decompression sickness appears to be about three to five times greater in those with PFO as compared to the general diving population, although the relationship is much weaker for only small openings.
Research has also found that high frequency divers have an increased likelihood of large and/or multiple brain lesions in those with PFO, particularly if the opening is large. This is not surprising, as bubbles passing into the brain can obstruct blood vessels.
PFO is often diagnosed by routine echocardiography, a simple procedure where sound is passed through the chest wall to the heart and its echo measured. If abnormalities are detected or suspected, this may be followed up with a more complicated echocardiogram where the sound transducer is passed down the esophagus to the region of the heart.
Despite the finding of increased risk of DCI in divers with PFO, the risk is still quite low. Most dive medicine experts do not recommend echocardiogram as a routine procedure in healthy divers. However, a history of unexpected DCS, especially Type II, or multiple episodes of any type, is reasons to further evaluate for the possibility of this cardiac defect."
You also mention having a heart murmur. This is not necessarily something else entirely from the general type of cardiac abnormality seen in PFO, but it does not arise from "very tiny" openings. A more severe form of this sort of abnormality is called atrial septal defect, and it does include heart murmur. However, this is a more serious condition with other signs & symptoms, such as fainting & a bluish or purplish tinge to the skin and mucous membranes noted at an early age.
Is there some possibility that you have a heart condition in addition to or other than PFO? Also, under what set of circumstances was your heart defect diagnosed?
Finally, you inquire if any organizations would allow you to train given knowledge of your status. Regardless of any disclaimer/waiver that you may be willing to sign, in the face of such a disorder any reputable agency will require written clearance from a physician.
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.
Best regards.
DocVikingo
they said that sometimes these can heal up, just wondered if anyone else has a hole in the heart and dives?
