Q4_Fall_2016_AlertDiver

he Patent Foramen Ovale and Fitness

to Dive Consensus Workshop was held

June 17, 2015, in Montreal, Canada.

The Undersea and Hyperbaric Medical

Society (UHMS) and DAN® invited

experts to review the current state of

knowledge about diagnosis of patent foramen ovale (PFO),

evaluation and mitigation of individual risk, and how

PFOs affect divers’ safety. DAN published the proceedings

of the workshop, including the consensus statement,

which are available online at

A PFO is a passage in the wall between the right and

left atria of the heart that can be found in about 25

percent of adults. Its size and the degree of blood flow

through it vary. In a small percentage of people, a PFO

allows for a continuous passage of blood from the right

atrium to the left atrium — a spontaneous right-to-left

shunt (RLS). In some people, the RLS occurs when

pressure in the right atrium exceeds pressure in the left

atrium. This may happen after relieving a temporary

obstruction to blood flow to the heart such as with a

Valsalva maneuver or straining while lifting, sniffing,

coughing or defecating. Spontaneous or provoked RLS

may be seen in 10-15 percent of adults.

A PFO with RLS has long been suspected for

paradoxical embolism, wherein particles carried

PATENT FORAMEN OVALE

AND FITNESS TO DIVE

By Petar J. Denoble, M.D.,

A surgeon prepares to place

an occluder in the heart

of a patient with a patent

foramen ovale (PFO).

BSIP/OTO/CHU BORDEAUX/SCIENCE PHOTO LIBRARY