DCI and Hole in the Heart

[alchemist117]

Does anyone know if much/any research has been done on links between DCI and hole in the heart syndrome? My sister is a congenital cardiac defect consultant and has had cases of people only being diagnosed with a hole in the heart after suffering a DCI incident.

 

[amascuba]

Hole in the Heart as in PFO? (Patent Foreman Ovale)

PFO, Patent Foramen Ovale in Adults - congenital heart disease

If you are talking about a PFO then there is quiet a bit of information out about this and the effects it can have on diving. The basic run down is that dissolved gases have the potential of traveling from the right side of the heart to the left side of the heart without being filtered by the lungs. So as the diver ascends the dissolved gases turn into bubbles creating symptoms of Decompression Sickness or Embolism.

http://www.diversalertnetwork.org/medical/articles/download/PFOart.pdf

DAN Divers Alert Network : Patent Foramen Ovale

DAN Divers Alert Network : Patent Foramen Ovale - Is It Important to Divers?

DAN Divers Alert Network : Patent Foramen Ovale (PFO)

Also, search this forum. There is quiet a bit of information about this on these forums.

Most people don't get tested for this unless there is a reason for it or it's requested by the patient.

 

[alchemist117]

I did mean PFO. Your info was the type of thing I was looking for.

 

[Dr. Doug Ebersole]

I'm a cardiologist who closes PFOs on a regular basis. Yes, PFO increases your risk of DCI -- and the feeling is that having a PFO probably doubles your risk. However, because the ABSOLUTE risk of any single diver suffering DCI is so small, by multiplying a very small number by two is still a very small number. For this reason, it is not recommended that divers routinely be screened for PFO. That having been said, if a diver suffers an "undeserved hit", it is reasonable to look for a PFO and, if one is found, close it.

 

[boomx5]

I'm a cardiologist who closes PFOs on a regular basis. Yes, PFO increases your risk of DCI -- and the feeling is that having a PFO probably doubles your risk. However, because the ABSOLUTE risk of any single diver suffering DCI is so small, by multiplying a very small number by two is still a very small number. For this reason, it is not recommended that divers routinely be screened for PFO. That having been said, if a diver suffers an "undeserved hit", it is reasonable to look for a PFO and, if one is found, close it.

Though there is a lot of info out there about PFO's, it would be nice if you could explain the proceedure of closing a PFO first hand. What kind of test do you recommend and is there anything on the horizon that is not as invasive as a TEE, but will be as effective as having a TEE done. Also, what is the success rate of having PFO closed, and is there any other reason besides diving (stroke maybe?) that would nessesitate a closure.

Thanks,

 

[mislav]

Can someone explain to me how does PFO increase the risk of DCI? What's the mechanism behind it?

 

[amascuba]

Can someone explain to me how does PFO increase the risk of DCI? What's the mechanism behind it?

Babies in the womb have a flap in the heart called a Patant Foraman Ovale (PFO) that allows blood to travel straight from the right atrium to the left atrium (I believe that is the path that it takes. I'm not a doctor, so maybe somebody can correct me if I mis-spoke), which bypasses the pulmonary artery for filtering gases by the lungs. After all, babies aren't able to breath on their own and don't need this filtering. When the baby is born the PFO is supposed to close up so that blood can travel the full course of the heart and begin filtering gases by the lungs, but in some people this fails to happen.

So as a divers body absorbs gases during a dive and the gases are dissolved in tissues and the blood these dissolved gases have the potential of bypassing the bodies natural filtering system and continue traveling through the body. As the diver ascends the dissolved gases grow into bubbles creating a DCS or embolism incident.

Here is a link to Al Star's blog about his PFO closure.
DIR Blog » Blog Archive » PFO Closure

I once saw some footage of some bodies PFO test and was actually able to see the PFO open and a rush of bubbles bypass the pulmonary artery. It was pretty freaky looking. I might have the link on a computer at home. I'll see if I can find it.

 

[Dr. Doug Ebersole]

Amascuba:

That was a very nice explanation of the situation of a PFO. Like mentioned above, the foramen ovale is supposed to seal after birth but in about 25% of people it doesn't. That means it is still "patent" (ie the term patent foramen ovale) which means the trap door is still functioning. Also as mentioned the lungs filter small bubbles that we all get while diving. However, if a bubble goes through the PFO it is directly into the systemic circulation where it can lodge in the brain (stroke), spinal cord (paralysis), heart (heart attack), etc.

While we divers are concerned about DCS, the main problem with PFO in the community is not an "undeserved hit" but an "undeserved stroke". The lungs also filter small clots that form in the leg and pelvic veins and break loose into the circulation. Like the analogy of the bubbles, a clot that crosses through the PFO can also result in bad outcomes. Most PFO closures are done for prior stroke with a much smaller number done for divers with DCS.

Previously, closing a PFO required open heart surgery. Now, however, it is done through a percutaneous procedure similar to a routine heart cath. A cahteter is placed into the femoral vein in the groin and advanced into the heart and across the PFO. A "clam shell"-like device is then deployed with one "disk" of the clam-shell on the left atrial side and the other on the right atrial side. This closes the PFO and your body then heals the area over. Most patients can go home the same day or the next day and are treated with a combination of Aspirin and Plavix for several months. The success rate of the procedure should be greater than 95% (nothing in medicine is 100%) and the complication rate is very low.

Hope this helps. A plug for a couple of magazines: There will be articles in the next issues of Advanced Diver Magazine (ADM Online) and Underwater Journal (Underwater Journal) that I helped write and wrote, respectively, that have drawings and actual cath and ultrasound images of the procedure.

Doug

 

[mislav]

Thanks guys. James, if you find that link, I'd be interested in seeing it.

 

[amascuba]

http://www.sdm.scot.nhs.uk/media/pfo2.mpg

Here is an ultrasound of a PFO opening up and bubbles rushing into the left atrium.