What Is a Patent Foramen Ovale (PFO)?
Why PFO Matters for Scuba Divers
During a dive, increased pressure causes more nitrogen to dissolve into the body’s tissues and blood. On ascent, this nitrogen comes out of solution and forms bubbles. Normally, these bubbles are filtered and trapped in the lungs before they can reach sensitive organs.
With a PFO in diving, some of these bubbles can cross from the right side of the heart to the left side, bypassing the lungs. From there, they can travel to the brain, spinal cord, or other organs. This can increase the risk of decompression sickness (DCS), particularly neurological DCS and, in rare cases, arterial gas embolism.
It is important to note that having a PFO does not automatically mean a diver will get decompression sickness. Many divers with a PFO never experience any problems. The risk is influenced by dive profiles, ascent behavior, and overall health.
Signs That May Suggest a PFO in Divers
Only proper medical testing can confirm a PFO, but certain patterns may lead a diving physician to suspect it:
- Unexplained or recurrent decompression sickness despite conservative dive profiles
- Neurological symptoms after diving, such as numbness, weakness, or visual disturbances
- DCS occurring after relatively shallow or non-aggressive dives
These signs do not prove the presence of a PFO, but they may justify further investigation with a cardiologist familiar with diving medicine.
How a PFO Is Diagnosed
If a diver and their doctor suspect a PFO, several diagnostic tests are available. The most common methods include:
- Bubble contrast echocardiography: An ultrasound of the heart performed while injecting microbubbles into a vein. If bubbles appear on the left side of the heart, it suggests a PFO.
- Transcranial Doppler ultrasound: Measures bubbles passing through brain vessels after bubble injection, indicating a right-to-left shunt.
- Other imaging: In some cases, cardiac MRI or CT may be used, though they are less common for routine PFO screening in divers.
These tests should be arranged and interpreted by a cardiologist or specialist with experience inPFO and diving.
Managing PFO Risk in Diving
Many divers with a PFO continue to dive safely by adjusting their behavior and dive planning. Key strategies include:
- Dive conservatively: Reduce depth and bottom time, extend safety stops, and use slower ascent rates than the minimum recommended.
- Avoid heavy exertion after diving: Strenuous activity can increase bubble movement and shunting.
- Stay well hydrated and rested: Good circulation and overall health support safer off-gassing.
- Plan longer surface intervals: Allow more time for nitrogen elimination between dives.
In some cases, especially after serious or recurrent DCS events, a cardiologist may discuss the option of PFO closure. This is usually done via a minimally invasive catheter procedure. The decision to close a PFO is highly individual and should be made together with a diving physician and cardiologist.
Diving After PFO Closure
Some divers choose to have their PFO closed and later return to diving. After closure, there is typically a period of healing and follow-up imaging to confirm that the shunt is effectively sealed. Only then will a doctor consider clearing the diver to return to the water.
Even after successful closure, most experts still recommend conservative dive profiles. Closure reduces the risk associated with right-to-left shunting, but it does not eliminate all decompression risk. Good dive practices remain essential.
Can You Dive Safely with a PFO?
The short answer is: yes, many divers with a PFO can dive safely, provided they understand the risks and adapt their diving accordingly. The key elements are:
- Awareness of your own medical status
- Consultation with a diving-aware physician
- Conservative dive planning and ascent behavior
- Prompt reporting of any unusual symptoms after diving
A PFO is just one factor in a diver’s overall risk profile. Good training, solid buoyancy control, slow ascents, and thoughtful dive planning remain the foundation of scuba diving safety.
Key Takeaways: PFO and Diving
- A Patent Foramen Ovale is common and often harmless on land.
- In diving, a PFO can allow bubbles to bypass the lungs and increase the risk of decompression sickness.
- Diagnosis requires medical testing such as bubble contrast echocardiography or transcranial Doppler.
- Risk can often be managed with conservative dive practices and, in some cases, PFO closure.
- Always seek advice from a doctor experienced in diving medicine before making decisions about diving with a PFO.