Sometimes the first symptom of a serious heart problem is sudden cardiac death (SCD). Silent heart conditions may exist, surfacing with fatal results. The tragedy is heightened when victims are young, seemingly healthy, athletes. Many U.S. school districts now require high school athletes to submit to a pre-participation physical exam before being allowed to play sports. That exam may include an electrocardiogram (ECG) to screen for heart abnormalities that could lead to SCD. But a study by the University of Houston finds that the practice may not accurately detect such abnormalities and may not be an efficient use of time or money.
"Using our statistical model, which is based on information and estimates in published reports, about 16 percent of high school athletes would have a positive ECG, but very few of those would actually have the cardiac abnormalities that could lead to SCD," said Dan O'Connor, assistant professor of health and human performance. "Total costs for the screening and subsequent medical follow-ups for those athletes could be in the millions of dollars annually across the United States."
O'Connor, who investigates the effectiveness of clinical interventions by applying biostatistical methods, used data from the National Federation of High School Associations and the U.S. Census Bureau School Enrollment in addition to a number of medical articles. He entered this information into mathematical equations to evaluate what might happen if all high school athletes received an ECG at their pre-participation exam.
"We are not suggesting that young athletes shouldn't exercise caution before beginning a sport. Certainly they should have a physical examination before playing, as recommended by a number of medical associations," he said. "However, we are encouraging athletic trainers, coaches, physicians and parents to be aware of what the ECG's results may convey - you will find a few athletes who have serious conditions, but you are going to get a lot of apparent abnormalities in normal, healthy kids."
O'Connor says there are a number of issues with ECG testing in teenagers, which include interpreting the results, differences in children's ECGs relative to adults and the rarity of serious heart conditions. O'Connor says when ECG is used for all young athletes, these issues combine to lead to a large number of "false positives," or athletes with abnormal ECGs who are actually healthy and at no risk for SCD.
"For example, for every teenage boy who actually has a cardiac abnormality and who is identified by ECG screening, about 50 boys with no abnormalities may have a positive ECG, which will often require further medical testing to rule out disease," O'Connor said. "If we add up the estimated total costs of administering the ECG and the subsequent medical tests for false positive results of the 2 to 3 million athletes entering high school each year in the U.S., it could exceed $126 million."
The "cost" of testing everyone, he said, would be evident not only in money, but in psychological stress of being falsely-labeled with a potentially fatal condition, and in the time an athlete may be removed from his/her sport in order to pursue costly follow-up exams. O'Connor says he hopes his study provides some reasonable expectations about adding ECG to pre-participation exams.
"A better strategy may be to test only those athletes who are at highest risk, such as those with a family history of heart problems or premature death, as well as other known risk factors," he said. "More study is needed of large populations of high school athletes, followed for many years, to determine the real prevalence of cardiac abnormalities, the occurrence and risk of sudden cardiac death and the accuracy of electrocardiograms in this setting."
The study is published in the June issue of Journal of Athletic Training.