When a young athlete suffers a sudden cardiac arrest during training or competition, the reaction is usually immediate: surprise, disbelief, and many questions. After all, we are talking about someone active, trained, and, in theory, healthy. How can the heart fail precisely in this context? Sudden cardiac arrest (SCA) in athletes is rare, but its impact is disproportionate to its frequency, precisely because it occurs in young individuals, often without a prior diagnosis of cardiovascular disease. Understanding what is behind these events is fundamental for those who work with health, sports, and performance.
An important point to make right from the start is that, in most cases, sudden cardiac arrest in young athletes is not related to a heart attack. The most common mechanism is a severe ventricular arrhythmia, which causes the heart to stop pumping blood effectively, usually during or shortly after intense exercise, when the heart is subjected to greater electrical and hemodynamic stress.
In practice, this usually happens in hearts that have some pre-existing, often silent, condition. Among the most frequently associated causes are:
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Hypertrophic cardiomyopathy;
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arrhythmogenic cardiomyopathy;
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congenital anomalies of the coronary arteries;
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myocarditis;
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Channelopathies, such as long QT syndrome and Brugada syndrome.
One striking finding from recent studies is that, in a significant portion of cases, autopsies show no evident structural alterations in the heart. In these scenarios, genetic testing, known as molecular autopsy, can identify variants associated with electrical disturbances in about a quarter of athletes. In other words, the problem lies not in the shape of the heart, but in the way its electrical signals are generated and conducted.
As we age, the profile changes. From the age of 35, the main cause of sudden cardiac arrest becomes atherosclerotic coronary artery disease, similar to what occurs in the general population. In this context, exercise acts as a trigger for arrhythmic events in a heart that already has established disease.
Given this, the question naturally arises: is it preventable? In many cases, yes. A well-conducted pre-participation evaluation remains one of the most important tools. When it includes a good medical history, investigation of family history, careful physical examination, and a 12-lead electrocardiogram, the chance of identifying conditions associated with sudden cardiac arrest increases significantly. The ECG, when interpreted by professionals trained in sports cardiology, can detect about two-thirds of diseases related to sudden death, with a low false-positive rate.
However, not all events are preventable. Therefore, emergency preparedness is as crucial as prevention. Survival after sudden cardiac arrest depends primarily on the time until defibrillation. Sports environments with well-defined action plans, teams trained in cardiopulmonary resuscitation, and rapid access to automated external defibrillators have significantly changed the prognosis of these cases.
Another point worth highlighting is that surviving a sudden cardiac arrest does not necessarily mean the end of sports practice. With accurate diagnosis, appropriate treatment, and specialized follow-up, many athletes are able to return to sports safely, based on individualized and shared decisions.
In summary, sudden cardiac arrest in athletes is rare, but requires continuous attention. The combination of adequate screening, prepared environments, and well-informed clinical decisions has allowed not only a reduction in mortality but also the preservation of sports practice with greater safety.
