"Based on this study, these subtle markers can help us predict who could be at risk for heart disease and heart attacks," said Angela Sharkey, M.D., associate professor of paediatrics at Washington University School of Medicine and a paediatric cardiologist at St. Louis Children's Hospital. For the study, Sharkey and Steven M. Lorch, M.D., a former fellow at the School of Medicine now at University of Texas Health Science Center at Houston, analyzed data from 168 children ages 10 to 18 who had been referred to them for cardiac ultrasound with symptoms including heart murmur, chest pain, acid reflux or high blood cholesterol.
Based on Centres for Disease Control and Prevention guidelines for body mass index for age (BMIA), 33 patients were found to have a BMIA as obese, or the 95th percentile or above for their age; 20 had a BMIA that classified them as at risk for obesity, or between the 85th and 94th percentile; and 115 were considered normal, or below the 85th percentile.
In order to analyse the hearts of the obese kids and those at risk, the researchers used a new tissue Doppler imaging technique called vector velocity imaging which tracks the movement of the heart's muscular wall.
Any changes in the rate of motion of heart muscle were averaged within each group and compared to the normal rate of motion.
"In the patients who are obese, the rate of motion of heart muscle changed. As a child's BMIA increases, we see alterations in both the relaxation and contraction phase of the heartbeat. Many of these changes that have been seen in adults were assumed to be from long-standing obesity, but it may be that these changes start much earlier in life than we thought," Sharkey said.
Sharkey said that the findings of the study give more ammunition to physicians to use in counselling paediatric patients and their parents about the risks of obesity and the need to attain a healthy weight.
"Even in teenagers, obesity leads to decreased myocardial performance and abnormal diastolic function," she said.
The study was published in the Winter 2007 issue of the Journal of Cardiometabolic Syndrome.