Athletes represent some of the healthiest people in society, so sudden cardiac arrest in this population often raises concern and curiosity. Why does this happen? To understand this, it is important to look at how the heart functions and what can go wrong, even in a seemingly healthy person.
The heart needs fuel and electricity
The heart is a pump that beats around 60 to 100 times per minute and nearly 1 lakh times a day. When this apparently healthy pump suddenly stops, it results in cardiac arrest.
Like any other pump, the heart needs fuel and electricity to function normally. The fuel is the blood supply to the heart, while the electricity refers to the heart’s electrical system, which controls its rhythm.
Any abnormality in the structure of the pump itself, such as a problem with the heart muscle, a sudden reduction in its blood supply, as can happen during a heart attack, or a sudden electrical failure in the form of a dangerous rhythm disorder can potentially cause the heart to stop.
Why are young athletes at risk?
Since athletes are generally younger, coronary artery disease, which causes most heart attacks, is an uncommon cause of sudden cardiac arrest in this group. Heart attacks become more common from the fourth decade onwards and are relatively rare in younger people.
However, anabolic steroids, which are sometimes used as performance-enhancing drugs, can increase blood pressure, cause thickening of the heart muscle and contribute to premature coronary artery disease in younger individuals.
In young athletes, abnormal heart muscle disorders called cardiomyopathies, cardiac rhythm disorders and congenital abnormalities of the coronary arteries are more likely causes of sudden cardiac arrest.
Interestingly, many of these conditions can be hereditary or congenital. A person may have the condition for years without experiencing any symptoms.
When exercise becomes a trigger
The increased adrenaline response and higher workload on the heart during intense exercise may trigger a fatal rhythm disturbance in a heart that already has an underlying condition.
Hypertrophic cardiomyopathy, for example, is a heart muscle disorder that is present in around one in 500 individuals. It is also recognised as an important cause of sudden cardiac death in athletes.
In this condition, the heart muscle becomes abnormally thickened. This can increase the risk of dangerous heart rhythms and sudden cardiac arrest, with intense exercise potentially acting as a trigger.
Can screening help?
Since many causes of sudden cardiac arrest in young athletes are hereditary or congenital, routine pre-competition screening can help identify some athletes who may be at higher risk.
An ECG, which records the heart’s electrical activity, and an echocardiogram, which looks at the structure and function of the heart, can help detect certain underlying abnormalities.
Data from several countries have shown that pre-competition cardiovascular screening can reduce the incidence of sudden cardiac death among athletes. The aim is not to stop young people from participating in sport, but to identify those who may have an underlying cardiac condition and need further evaluation before engaging in intense physical activity.
-Dr Maneesh Rai is a Cardiac Electrophysiologist at KMC Hospital, Mangalore