Dr. Angela Sharkey of Washington University School of Medicine in St. Louis and Dr. Steven M. Lorch of the 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 Centers for Disease Control and Prevention guidelines for body mass index for age -- or 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. To analyze the hearts of the obese children and those at risk, Sharkey and Lorch used a new tissue Doppler imaging technique called vector velocity imaging.

"As a child's BMIA increases, we see alterations in both the relaxation and contraction phase of the heartbeat," Sharkey said in a statement. "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."

The findings were published in the Journal of Cardiometabolic Syndrome.