Screening Student Athletes: Controversies and Benefits

Sudden cardiac death (SCD) is caused by ventricular fibrillation (an irregular heart rhythm from the lower chambers of the heart) and is almost always fatal.  Sudden cardiac death does occur in athletes. Young athletes have an increased risk of SCD compared to their non-athlete peers. The combination of physical exercise and an underlying heart disorder in an athlete can trigger cardiac arrest. The incidence of SCD in athletes varies widely, from about 1 in 150,000 in high school athletes to 1 in 53,000 in college athletes. The rate of SCD in NCAA athletes is highest in males, black athletes and in basketball players.  Screening athletes for their risk for SCD has been shown to reduce the rate of SCD, but the best method of screening remains controversial.

The American Heart Association (AHA) recommends a 14-point history and physical examination to be used for athletes prior to participation in sports. In Europe and in other parts of the world, screening is performed using a questionnaire plus an electrocardiogram (EKG), a test that detects the electrical activity of the heart. The AHA does not recommend an EKG. In both cases if the athlete is felt to be at risk, further cardiac testing including an echocardiogram (an ultrasound of the heart) is performed.  The biggest controversy in screening is therefore whether to include an EKG or not.  This controversy centers on the ability of an EKG to accurately detect heart abnormalities known to cause SCD in athletes.  Intense athletic conditioning changes the structure of the heart and these changes may be reflected in the EKG.  An athlete’s EKG can mimic the EKG of a patient with significant heart disease. Therefore, accurate interpretation of EKGs requires extra training and lots of experience reading athletes’ EKGs.  The reader must be able to discern whether findings on an EKG are normal for the athlete or whether it points to heart disease. False positive testing occurs when a test (such as an EKG) is abnormal but the patient does not have a disease and in fact is normal.  The screening questionnaire has never been shown to accurately identify heart conditions that put an athlete at risk for SCD.  It may have a false positive rate of 30%,  which is considered quite high. The EKG false positive rate is around 11-22%. The Seattle criteria, introduced in 2012, tightened up the guidelines for reading EKGs in athletes and have decreased the false positive rate to 2.5-6%. By using the Seattle criteria an athlete’s EKG can be correctly identified and can lessen the need to do further cardiac testing. Adding the EKG to the screening process has resulted in other controversies as well, including the cost of doing the EKG (and the subsequent cost of cardiac testing for false positive EKGs), the emotional cost of an abnormal EKG (being disqualified from playing sports) and the financial cost if a scholarship or professional contract is forfeited.

Additional controversies in screening include the fact that not all heart diseases that can cause SCD can be identified (even with the addition of an EKG and echo). Having a normal screening might provide a false sense of security.  In addition, the screening generally targets young adults.  The athlete may be genetically programmed to have a disease causing SCD, but it cannot yet be detected by screening since the athlete is still growing and maturing.  Lastly, it is not known how often to do cardiac screening, whether it is a one-time event or whether it should be repeated every few years until the athlete has finished growing.

Certainly the biggest benefit to screening is the correct identification of a heart abnormality associated with SCD. In this case, the athlete is held out from competition and appropriate treatment is begun, both potentially life-saving moves. The incidence of heart disease associated with SCD in the general population is about 1 in 500 to 1 in 1000, so the vast majority of athletes undergoing screening are not identified with disease. Despite that, screening is still beneficial to the athlete. Just by participating in the screening, the athlete and the family are educated about the signs and symptoms which may precede SCD.  Heightening the awareness of SCD in the community can potentially be life-saving as well. Lastly and most surprisingly, many athletes are identified with an elevated body mass index (obesity) or an elevated blood pressure (hypertension), both measured at screening. Since the majority of these young adults would likely not see a doctor for many years, the screening can identify potential future problems for them, allowing them to make lifestyle changes early on in their lives and well before heart disease begins to manifest.