The way physicians measure one of the most important cardiovascular risk factors in children may not be the most accurate, leading to less than optimal treatment and outcomes.
Heavier weight of the heart’s left ventricle is a known risk factor for heart attack or stroke. Left ventricular mass typically has been measured by echocardiograph, and risk depends on deviation from what’s considered "normal.” Researchers at Cincinnati Children’s Hospital Medical Center believe that the complex relationship between heart growth and body growth in children has led to an inaccurate baseline.
The study is published in the June issue of the Journal of the American Society of Echocardiography.
"The pediatric community has been measuring left ventricular mass (LVM) in myriad ways,” says Tom Kimball, MD, a cardiologist at Cincinnati Children’s and the study’s main author. "Without an accurate measure relative to a patient’s size, it’s impossible to determine what’s normal.”
The goal of indexing methods -- measuring LVM compared to a patient’s size – is to account for differing body sizes without discounting the adverse effects of being overweight or obese on the heart.
Kimball and his colleagues studied echocardiograms of 2,273 infants and children up to 18 years old. They knew the best indexing measure was a child’s lean body mass, which is difficult to determine. They discovered that a mathematical formula based on a patient’s height alone may be the best method, because it approximates lean body mass and takes into account growth occurring in children without discounting the bad effects of being overweight on the left ventricle.
They established normal values for LVM across the pediatric age range. These values can be used to determine if a child’s LVM is high and whether the child is at increased risk of future heart attack or stroke.
"It’s essential that cardiologists have an accurate assessment of their patients’ left ventricular mass status to help them make informed decisions,” says Kimball, professor of pediatrics at the University of Cincinnati College of Medicine. "We plan to make age-based percentiles part of national education efforts to help physicians attain this goal.”