Heart Defects Can Delay Baby's Brain Development

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The team also found a decrease of 10 percent in the ratio of N-acetylaspartate (NAA) to choline, and an increase of 28 percent in the ratio of lactate to choline. These are surrogate measures for metabolic brain development, explained study co-researcher Dr. Patrick McQuillen. McQuillen practices Pediatric Critical Care Medicine and Pediatrics in San Francisco, California.

Previous studies have shown that lower levels of NAA and higher levels of lactate were associated with an increased risk of neurodevelopmental impairment in infancy and childhood.

The researchers also found an increase of 4 percent in what's knows as diffusivity, a measure of brain tissue structure. According to Miller, as a brain develops more complex tissues, there are usually more barriers to water diffusing through tissues, which means that diffusivity decreases with maturity.

Finally, babies with heart defects also displayed a decrease of 12 percent in white-matter fractional anisotropy, meaning the brain's white matter was less mature.

"White matter injury, the characteristic pattern of injury in the premature newborn, was surprisingly common in the newborns with heart disease that we studied," said study lead author Dr. Steven Miller, assistant professor of pediatrics at the University of British Columbia.

White matter does have some capacity to heal itself following injury, a process known as remyelination, which may involve injured cells repairing themselves or new cells being produced, the researchers said.

"It is very important to note that babies with heart disease have the potential for ongoing brain development and even recovery if there is injury," said McQuillen.

Better imaging technologies are helping identify babies with heart defects in utero, which means parents can plan for the birth at a facility that provides care and surgery to these infants. Many times, congenital heart defects are diagnosed soon after birth, said McQuillen. However, some infants still go home and become very ill before their condition is recognized, he added.