According to a study published in the European Society of Cardiology, recommendations on how to use gene testing to prevent sudden cardiac death in athletes and enable safe exercise are paving the way. “Genetic testing for potentially lethal variants is more accessible than ever before and this paper focuses on which athletes should be tested and when,” said author Dr. Michael Papadakis of St George’s, University of London, UK. “Athletes should be advised of the potential results prior to genetic testing as this could mean exclusion or restricted play.” (Also read: Cardiologist on how singer KK’s heart attack should have been handled better)
In most cases, the clinical evaluation will determine the need for preventive therapy such as a defibrillator and advice about exercise and participation in competitive sports. dr. Papadakis explains, “Even if a genetic abnormality is found, treatment recommendations and return to play usually depend on how severe the disease is clinically. Does it cause symptoms like fainting? Is the heart unusually weak or thick? Can we tell many irregularities of the heart rhythm (arrhythmias) and do they get worse with exercise? If the answer is yes to any of these questions, then the game is probably limited in some way.”
One example is an inherited condition that can cause sudden cardiac death in athletes called hypertrophic cardiomyopathy (HCM), in which the heart muscle is abnormally thick. dr. Papadakis noted, “We used to be very conservative, but now our advice is more liberal. Athletes with HCM should undergo a comprehensive clinical evaluation to assess their risk of sudden cardiac death and then they should be prescribed exercise. Genetic testing in this condition does not affect management in most cases. Asymptomatic athletes who are believed to be at low risk may be able to participate in competitive sports after an informed discussion with their doctor. Others at higher risk may be limited to moderate-intensity exercise. The prescription for the exercise should be so specific and outline how often, for how long, at what intensity, and what movement or sport is safe.”
However, in some cases, genetic testing may dictate management. An example is long QT syndrome (LQTS), an inherited electrical malfunction of the heart. Identification of different genetic subtypes (LQT 1-3) can indicate arrhythmia risk, identify potential triggers that should be avoided, and help direct medical therapies and plan exercise advice. dr. Papadakis said, “For example, sudden immersion in cold water causes more life-threatening arrhythmias in LQT type 1 rather than type 2 or 3, so one should be more careful with swimmers who have the type 1 genetic subtype than runners.”
The only situation where genetic testing alone can lead to exclusion from play is a heart muscle condition called arrhythmogenic cardiomyopathy (ARVC). “Even if an athlete has no clinical evidence of the disease but does have the gene for the condition, he or she should refrain from intense and competitive sports,” said Dr. Papadakis.2 “This is because studies show that people with the gene who exercise at a high level tend to develop the disease earlier in life and tend to develop a more serious disease that can cause a life-threatening arrhythmia.” while doing sports.”
Pre-test genetic counseling should be conducted to discuss the implications for athletes and their families. For example, an athlete’s mother is clinically diagnosed with ARVC and has the causal gene, the athlete is then screened and all clinical tests are normal. The athlete has two choices: 1) clinical monitoring, probably yearly, to check for signs of illness; or 2) genetic testing. “The athlete should know that if the test is positive, it could mean the end of his or her career, even if there is no clinical evidence of disease,” said Dr. papadakis. “On the other hand, if genetic testing is refused, the condition may worsen. Post-test counseling is critical given the potential psychosocial, financial and mental health consequences, especially if the athlete is excluded from the game.”
Pediatric athletes may require genetic counseling in a specialized pediatric center with the help of a pediatric mental health specialist. dr. Papadakis pointed out, “The psychological impact of a positive genetic test result can be significant for the child, especially if it leads to exclusion from sports, even in the absence of clinical disease, as with ARVC.”
In children with a clinical diagnosis of a hereditary condition, genetic testing can confirm the diagnosis and, in some cases, help predict the risk of sudden death during exercise. For example, the gene for an electrical malfunction of the heart called catecholaminergic polymorphic ventricular tachycardia (CPVT) can lead to advice for preventive therapies, such as beta-blockers, and dictate exercise decisions. “This is important because CPVT is prone to arrhythmias during exercise and can cause sudden death at a very young age,” said Dr. papadakis. “In contrast, the timing of genetic testing in children with a family history of HCM is controversial, as it rarely causes sudden death in childhood in the absence of clinical signs.”
The Scientific Statement has been prepared by the Sports Cardiology and Exercise Section of the European Association of Preventive Cardiology, the European Heart Rhythm Association, the ESC Working group on myocardial and pericardial disease, the ESC Council on Cardiovascular Genomics, the European Society of Human Genetics and the Association for European Pediatric and Congenital Cardiology.
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