Pearl of diving medicine: Common heart ailment linked to deadly decompression sickness


BREAKTHROUGH medical research by a Tasmanian ­hyperbaric expert linking heart defects in divers to ­decompression illness is set to increase marine industry ­safety across the world.

Royal Hobart Hospital’s diving medicine expert David Smart, whose team’s contin­uing work with Tasmania’s $500 million aquaculture ­industry has helped the state achieve world’s best practice for diver safety, co-­authored a position statement on cardio screening tests for underwater workers that will soon become official policy worldwide.

“In 2013, one of our topical subjects was holes in the heart and how they relate to diving,” said Dr Smart, who is also an associate professor with the University of Tasmania School of Medicine.”

“It might sound strange but about a quarter of the adult population has a small hole between the left and right sides of their heart, which is a vestige of our time in the womb.

“This hole usually closes off pretty quickly after birth but in a percentage of us a little flap valve is left that sometimes opens and sometimes doesn’t.


“Day-to-day this is not very relevant but in divers it can cause ser­ious decompression sickness because it can cause gas ­bubbles in the blood to be transferred to the brain.”

Dr Smart, who won the 2014 Oceaneering Award for excellence in commercial ­diving from the Undersea and Hyperbaric Medical Society, said although routine screening for heart holes, or PFOs, was not justifiable, high-risk groups including divers with a history of ­cerebral or inner-ear decompression illness, migraine with aura or a family history of PFO, should consider medical testing.

Where heart holes were present, a reduction in gas load by limiting depth and repetitive dives might be appropriate, and divers with diagnosed PFOs might also consider ­having their holes surgically closed.

Dr Smart said divers should not take any action without first consulting a qualified diving medicine doctor.

“After I was invited to Montreal to present what had by then become a national position paper, the Undersea and Hyperbaric Medical Society took on most of its recommendations for it to become a world document,” he said. “It’s pretty satisfying for something that started locally to become international guidelines.”








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