DIVE LOG AUSTRALASIA FEB 2025 ISSUE 410

days, always well withing decompression limits and always on nitrox if it was available. The symptoms were always resolved by the morning. I suspected I may have a PFO but was not sure how to proceed. Advice was conflicting. Specialists from outside of Australia advised not to test as closure of the PFO was very expensive and not covered by their health care insurers. And if a PFO was found then it was unlikely I could get diving insurance unless it was closed. So just limit dives and diving days instead of further investigations. At this meeting I was able to speak with an Australian Cardiologist who advised me that PFO risks increased with age and that closure in Australia would be covered by our public hospital system. He also explained that a PFO can also be associated with stroke. In view of this, I saw a local interventional cardiologist in Cairns for assessment. Diagnosis is simple and involves a transthoracic echocardiogram (TTE) under the supervision of an experienced cardiologist. Agitated contrast is injected into a vein while the heart is imaged. The bubbles can be seen entering the R side of the heart and then the bubbles are filtered out by the lungs and disappear. However, if a PFO is present, the bubbles may flow freely through the defect into the L side of the heart, as they did with Cathie. From here the bubbles can pumped up to the brain and the rest of the body without being filtered. If bubbles are not seen entering the L side of the heart, the diver is asked to Valsalva (like clearing your ears). This increases the pressure in the R side of the heart and may cause the PFO to open and shunt. This is what happened to me. My PFO was diagnosed, I had it closed with a complex but fairy non-invasive procedure, was home the following day and back diving 4 months later. Happy Days. I have had no migraines since, and every dive when I am exerting myself in current or struggling to get up the boat ladder with my gear on, I am thankful for the closure. When Cathie came to see me in January 2024 with her story of marine sting resulting in a rash on her abdomen, painful breasts and swollen arm, I immediately suspected she had a PFO. And indeed, she did and her PFO was shunting at rest without any provocation, making her at significant risk of further, not only skin bends, but significant neurological bends and stroke. The PFO closure takes place in a theatre specifically set up for cardiac interventional procedures. The closure is not actual surgery. The device is threaded up the femoral vein in a wire at the groin, up into the heart and then through the

defect in the artium wall (the PFO) from the R side to the L. It is then withdrawn after deploying part of the device on the L side of the defect and then the other part on the R side of the defect. The discs are then pulled together as the wire is withdrawn, leaving the device closing the defect. Below is a link to an animated video of the procedure. PFO closure animation After the procedure you are on two blood thinners for a month, then aspirin only for 6 months. At 3 months, another Trans Thoracic Echocardiogram (TTE) is performed to make sure that the device is in place and there is no further shunting. If this is all according to plan, then diving can be recommenced. The important thing to remember is to take antibiotics prior to dental procedures to prevent bacteria from settling on the device and causing infection. The body covers the device with epithelial cells and so it becomes just part of the atrial wall in time. As Cathie has written, it is important to recognise the symptoms and see a diving doctor if there are concerns. A PFO can result in significant spinal decompression illness, inner ear decompression illness, as well as skin bends, but more importantly it can also lead to stroke. The take home message is if you have concerns, see a diving doctor, get tested, and if you have a PFO, get it closed. It makes future diving less risky and less concerning.

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DIVE LOG Australasia #410 - February‘25

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