- Decompression sickness (DCS)
“Decompression sickness is a big concern for those who scuba dive because when a diver re-surfaces, the release of nitrogen bubbles can cause a stroke if these bubbles cross the PFO,” said Asst Prof Foo.
The DCS risk in recreational divers has been reported at 3.6 cases per 10,000 dives, and a four-fold increase in risk with PFO, according to Divers Alert Network. “The overall risk of neurological DCS is low, even in the presence of a PFO,” noted the website.
- Platypnea-orthodeoxia Syndrome (POS)
PFO can also lead to a rare condition known as platypnea-orthodeoxia syndrome, said Asst Prof Foo, “where a loss of oxygen saturation in the blood is observed” when you go from an upright to lying position.
HOW IS PFO USUALLY DETECTED SINCE THERE ARE NO SYMPTOMS?
According to Dr Kuntjoro, “it is often discovered incidentally when a patient undergoes an echocardiography (an ultrasound of the heart), or CT coronary angiogram for other cardiac conditions”.
The diagnostic test to ask your doctor about, advised Asst Prof Foo, is the trans-oesophageal echocardiogram with bubble contrast. “It involves inserting a small tube with an ultrasound transducer on its tip down the throat to visualise the heart and inject tiny bubbles into the bloodstream to check for the presence of a PFO,” he said.
“A transcranial doppler is also a good screening test,” added Asst Prof Foo. “This test uses ultrasound to examine the blood flow in the brain and can help detect any bubbles that cross a PFO.”
