Older children with surgically repaired hypoplastic left heart syndrome have poorer exercise tolerance than their younger counterparts, researchers report in the April issue of the Journal of Pediatrics.

"Older children with surgically repaired hypoplastic left heart syndrome have poorer exercise tolerance than their younger counterparts, researchers report in the April issue of the Journal of Pediatrics.

"An exercise program starting in early childhood," lead investigator Dr. Pamela C. Jenkins of Dartmouth Medical School, Hanover, New Hampshire, told Reuters Health, "may help delay any age-related decline in physical abilities."

Dr. Jenkins and colleagues studied 42 children with a mean age of 12.9 years. Twenty who had had heart transplantation and 14 who had undergone staged surgery completed metabolic assessment. The results were compared with norms for age and sex.

Children ages eight to 12 years achieved 70 per cent of predicted maximal oxygen uptake compared with 60 per cent for children ages 13 to 17 years. These findings did not differ significantly between transplant and staged surgery groups.

There was also a trend towards higher predicted peak heart rate in younger patients (83 per cent versus 75 per cent). Electrocardiographic changes were more common in older children.

In treadmill testing, transplant patients did better in predicted heart rate (82 per cent) than did those with staged surgery (66 per cent).

"Although babies with hypoplastic left heart syndrome who received a heart transplant had better exercise tolerance as teenagers than did babies who received staged surgery," Dr. Jenkins continued, "the implications of this finding are limited by the low availability of donor hearts."

"We also found," she added, "that exercise ability is a major component of how healthy parents perceive their child with hypoplastic left heart syndrome to be. So improving exercise performance may be the most powerful way to improve quality of life for these children and their families."

In an accompanying editorial, Dr. Reginald L. Washington of the University of Colorado School of Medicine, Denver, agrees, but also points out that certain children may have restrictions that limit the ability to increase heart rate during exercise. There may be pulmonary and other problems that limit the impact of physical rehabilitation."