Heart Defects Can Delay Baby's Brain Development

By Madeline Vann
HealthDay Reporter
Thursday, November 8, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, Nov. 7 (HealthDay News) -- Brain development is delayed in babies born with certain heart defects, new research shows.

The slowdown in brain development is similar to the delay found in premature infants, the researchers added.

Babies who require heart surgery have long been known to experience developmental delays, but whether the delays were due to the surgery or other factors has been in debate.

Now, a study published in the Nov. 8 issue of the New England Journal of Medicine shows that these brain abnormalities exist before the surgery.

"This is one of the first studies to say they have a true difference [in brain development] before they have surgery," says pediatric cardiologist Vidu Garg, assistant professor of pediatrics and molecular biology at the University of Texas Southwestern Medical Center and a pediatric cardiologist at Children's Medical Center, Dallas.

"It's been known that kids don't do well after open heart surgery. The relationship between congenital heart defects and brain development has not been known but has been hypothesized," said Garg, who was not involved in the study.

According to the U.S. National Institutes of Health, congenital heart defects cause more deaths among newborns than any other birth defects. Slightly less than one percent of American babies, or about 35,000 annually, have a congenital heart defect, according to the American Heart Association.

In the study, a team from the University of California, San Francisco, and at the University of British Columbia, Vancouver, examined 41 infants born with congenital heart disease. Twenty-nine had transposition of the great arteries and 12 had single-ventricle physiology. The researchers used magnetic resonance imaging (MRI) to analyze measures of brain development in each infant, including diffusivity and white-matter tracts.

White matter is the tissue through which nerve cells in the brain and nervous system communicate. Although the babies in the study had the same amount of white matter as babies without heart defects, the white matter was less mature and therefore at greater risk of injury, due to stressors like reduced blood oxygen levels. White-matter injury was observed in 13 of the 41 infants.