When a young or professional athlete suffers a cardiac event on the field or court, news media highlight the paradoxical tragedy: a young, apparently healthy person struck by an unexpected, often fatal condition. Manesh R. Patel, MD, chief of cardiology at Duke, co-authored a study published in Circulation, showing that sudden cardiac death was the most common medical cause of death among NCAA athletes in the 21st century.

Although evidence does not suggest that athletes are more prone to cardiovascular anomalies than the general population, increased activity may reveal congenital heart problems dramatically. Screening can detect some anomalies before they become fatal, says electrophysiologist James P. Daubert, MD, senior vice chief of cardiology at Duke. Along with cardiologist William E. Kraus, MD, Daubert serves as co-course director of Duke’s Sports Cardiology Symposium held annually in April.

Studies have shown that certain demographics and sports are more likely to suffer from serious cardiac events, including male athletes; athletes with African ancestry; and basketball, soccer, or football athletes. A partial explanation for some of the associations may relate to larger heart size. Duke University athletes are routinely screened with ECGs, and Daubert’s team is creating a registry to study the ECG findings over the past decade, with support from the Gary and Jackie Davis Family Foundation. The foundation also sponsors the Sports Cardiology Symposium, focused on preventing sudden cardiac arrest in athletes and advancing knowledge regarding cardiovascular adaptation and risk with sports.

“Screening is challenging,” Daubert acknowledges. “If we screen all athletes for rare conditions, electrocardiograms could potentially generate more false than true positives (abnormalities). Moreover, we can’t detect every abnormality. An important goal is to avoid disqualifying healthy athletes.”

For referring physicians, Daubert recommends monitoring symptoms of shortness of breath and fainting, then using an ECG to begin looking for anomalies. “In our exercise stress tests, we try to replicate the conditions that have previously caused symptoms in the athlete,” Daubert says.

“If you adjust the criteria and recognize the normal variation in athletes’ ECGs, such as a longer QT interval, slower heart rate, and other changes, you don’t unnecessarily disqualify very many athletes,” Daubert says. Not all anomalies will show on ECGs, sometimes requiring echocardiograms or cardiac MRIs to identify.

In addition to advanced imaging capabilities, Duke has broad expertise in the sports cardiology group as well as genetic counselors to select testing for rare conditions within the Adult Cardiovascular Genetic Clinic. For patients with serious risks, Duke physicians can guide medical therapy or place a device such as an implantable cardioverter-defibrillator.

An abnormal finding on ECG or other testing is not automatically disqualifying. “More and more, we’re using shared decision-making, explaining the condition and the risks. After learning of their potential risk, some athletes decide not to compete; but, in many cases, we say they can participate,” Daubert says. Close collaboration with athletic trainers is crucial. “Based on registry data, we have good evidence that, in general, at least moderate exercise for people with these conditions is safe and beneficial.”

“We see a wide variety of causes for cardiac events in athletes, including high school, college, and professionals,” Daubert says. “Early literature said that hypertrophic cardiomyopathy [HCM] was the most common cause, but more recent data shows that electrical problems are also an important contributor.” For nearly 20% of NCAA athletes with sudden cardiac death, their hearts showed no structural abnormalities, suggesting rhythm problems as a cause.

These electrical problems can include inherited conditions not previously diagnosed in the family that can cause life-threatening arrhythmias, such as long QT syndrome, Brugada syndrome, or catecholaminergic polymorphic ventricular tachycardia. HCM is one of the most common structural causes, followed by arrhythmogenic right ventricular cardiomyopathy (formerly dysplasia), anomalous coronary arteries, and myocarditis.

When cardiac events do occur, whether in athletes or the general population, accessible AEDs and CPR training remain vital interventions. Duke research has recently shown that bystanders are more likely to perform CPR with instructions from 9-1-1 operators and has helped some North Carolina counties to deliver AEDs via drone to emergency situations within the crucial five-minute window.