New Recommendations Show How to Use Genetic Testing to Prevent Sudden Cardiac Death

New recommendations on how to use genetic testing to prevent sudden cardiac death in athletes and enable safe exercise have been published in the European Journal of Preventive Cardiology..

“Genetic testing for potentially lethal variants is more accessible than ever before, and this document focuses on which athletes should be tested and when,” Michael Papadakis of St George’s, University of London, said in a statement. “Sportspeople should be counselled on the potential outcomes prior to genetic testing, since it could mean exclusion or restricted play.”

In most cases, clinical evaluation will dictate the need for preventive therapy, such as a defibrillator, and advice on exercising and participation in competitive sports.

Recommendations on treatment and returning to sports depends on how severe the disease is clinically, even if a genetic abnormality is found, Papadakis said.

“Is it causing symptoms such as fainting? Is the heart excessively weak or thick? Can we see many irregularities of the heart rhythm [arrhythmias], and do they get worse during exercise? If the answer is ‘yes’ to any of these questions, then play is likely to be curtailed in some way,” Papadakis said.

An example could be an inherited condition hypertrophic cardiomyopathy (HMC), which causes the heart muscles to be abnormally thick and can cause sudden cardiac death in athletes. Papadakis noted that athletes who have HCM should undergo comprehensive clinical evaluations to assess their risk of sudden cardiac death, so that they can be offered an exercise prescription.

Asymptomatic athletes who are at low risk can potentially participate in competitive sports after a discussion with their physicians, while those at higher risk may be restricted to moderate intensity exercise, he said.

An exercise prescription should be as specific as possible to outline how long and often and what exercises at what intensity or sport is safe to the individual.

However, genetic testing can help physicians advise management. In long QT syndrome (LQTS), which is an inherited electrical fault of the heart, identification of different genetic subtypes of LQTS can help inform the risk of arrhythmias, identify potential triggers, and help plan exercise advice and target medical therapies.

“For instance, sudden immersion in cold water is more likely to cause life-threatening arrhythmias in LQT type 1 rather than types 2 or 3, so one should be more cautious with swimmers who have the type 1 genetic subtype than runners,” Papadakis said.

The only situation where genetic testing alone may result in exclusion from play is if a heart muscle condition, arrhythmogenic cardiomyopathy (ARVC), is present.

Even if an athlete has no clinical evidence of the disease but has the gene for the condition, the individual should abstain from competitive and high-intensity sports, Papadakis said

Studies show that individuals with this gene who exercise at a high level tend to develop the disease earlier in life and tend to develop more severe disease, which can cause a life-threatening arrhythmia during a sport, he said.

Pre-test genetic counselling should also be performed to discuss the implications for athletes and their family.

“The athlete needs to know that if the test is positive that may signal the end of his or her career, even if there is no clinical evidence of disease,” Papadakis said.

“On the other hand, if genetic testing is refused the condition may get worse,” he said. “Post-test counselling is critical given the potential psychosocial, financial, and mental health implications, particularly if the athlete is excluded from play.”

For children, genetic counseling in an expert pediatric center with assistance from a child mental health specialist could be needed, Papadakis said.

For children with a clinical diagnosis of an inherited condition, genetic testing could confirm the diagnosis and could, in some cases, help predict the risk of sudden death during sports. For example, having the gene for an electrical fault of the heart, called catecholaminergic polymorphic ventricular tachycardia, could lead to advice for preventive therapies, such as beta blockers and dictate decisions about exercises.

Reference

Up to 80% of athletes who die suddenly had no symptoms or family history of heart disease. EurekAlert. News release. June 16, 2022. Accessed June 22, 2022. https://www.eurekalert.org/news-releases/955940