Sudden Cardiac Death in Athletes
Winning a gold medal at the Olympics or scoring a goal that wins the World Cup are amongst the highest aspirations of athletes from an early age. Young players train hard for many years with this vision and are regarded as some of the top athletes in their country. It is therefore not only a tragedy but totally unexpected when young athletes die suddenly often during competitive sports.
Sudden cardiac death affects between 0.5 and 1 in 100,000 athletes per year. This is not very common, but such deaths are usually high profile. This risk, which increases with age, is also related to the athlete’s intensity of training and level of fitness. This usually affects men more than women and football players die more often compared to all other sports as this is the sport played by most persons on the planet. The sport itself is not the cause of sudden cardiac death, but is the trigger in those people with pre-existing (usually unknown) heart defects. Over the age of 35 the commonest cause of sudden cardiac death is coronary artery disease. Under the age of 35 it is usually due to an inherited condition. Occasionally viral or bacterial infections can affect the heart (myocarditis) at any age and can also cause sudden cardiac death. It is estimated that 12 young people under the age of 35 die from sudden cardiac death every week in the UK.
The main cause of sudden cardiac death in athletes under the age of 35 is Hypertrophic Cardiomyopathy (HCM). This condition is present in 1 in 500 of the general population and is usually passed down through generations and causes the heart muscle to grow much thicker than it should. As a result this abnormal heart muscle can cause dangerous, fast heart rhythms to develop which can lead to sudden cardiac death. When athletes train this abnormal muscle can grow even thicker, thereby increasing the risk. If an athlete with this condition were not to compete in competitive sports their risk would be lower.
There are other structural heart conditions which can cause sudden cardiac death, such as Arrythmogenic Right Ventricular Cardiomyopathy (ARVC) in which heart muscle is replaced by fatty tissue. This fatty tissue can also cause these abnormal heart rhythms and sudden death. Another situation which can cause sudden cardiac death is when the coronary arteries which send blood to the heart muscle take a wrong course around the heart (coronary artery anomalies). Sudden death can occur on exercise when these arteries are squashed by other structures close to the heart.
There is also a whole group of conditions in which the ‘electrical wiring’ of the heart is abnormal again leading to the development of dangerous heart rhythms and sudden death (such as Long QT syndrome). These may have specific triggers; one condition is triggered by noise (which has caused some people to die when their alarm clock goes off in the morning) and another is triggered by water (which can be triggered by diving in to a swimming pool!)
Usually most of these conditions have warning signs and it is quite common for athletes to have reported certain symptoms for a while before they die suddenly. The following symptoms should not be ignored and investigated:
-Rapid heart beat or breathlessness persisting after exercise has stopped
-Dizziness and fainting during or just after exercise
-Chest pain which can spread to arm, jaw neck, back and abdomen during or just after exercise.