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January 1, 2001
Divers with Heart Defect at Risk for More Brain Lesions
By REUTERS
Filed at 5:32 p.m. ET
NEW YORK (Reuters Health) - Scuba divers with a small opening between the upper heart chambers, which normally closes shortly after birth, may be over four times as likely as other divers to experience decompression illness, according to new study results. They may also have twice as many areas of injury to the brain, suggesting decreased blood flow to the brain.
The study, which was conducted jointly by scientists at the Swiss Cardiovascular Center and University Hospital both in Bern, Switzerland, appears in the January 2nd issue of Annals of Internal Medicine.
The researchers, led by Dr. Markus Schwerzmann, used magnetic resonance imaging (MRI) to look for brain lesions in a group of 52 experienced scuba divers, who had completed 200 scuba dives and had no obvious health problems, and 52 healthy nondivers.
The study subjects also underwent ultrasound examination to detect a common heart defect known as a patent foramen ovale. Ordinarily, if this type of heart opening is small it would not pose a threat to health, and the affected individual could go through life unaware of its presence.
According to the authors, the heart defect was found in 13 of the divers and 9 of the nondivers.
They report that divers with patent foramen ovale were at 4.5 times as likely to have experienced episodes of the potentially life-threatening condition known as decompression syndrome, compared to divers with normal hearts.
The authors also detected twice as many lesions in the brains of divers with patent foramen ovale compared with divers who did not have the defect.
Given these findings, they emphasize that ``diving itself, more than diving in the presence of a patent foramen ovale, is associated with the presence of...brain lesions compared with persons who do not dive.''
Previous studies have shown that divers had more brain lesions than non-divers. Many experts attribute this to the effects of gas embolism--large bubbles of nitrogen gas that can form in the veins under pressure, commonly known as ``the bends.'' Other studies have shown that experienced deep-sea divers often develop poor brain functioning after several years.
SOURCE: Annals of Internal Medicine 2001;134:21-24.
http://www.online.reuters.com/>Copyright 2001 Reuters Ltd.
