Improving the diagnosis of heart diseases in Black athletes

Sudden cardiac death is the most common cause of death in athletes during sport and exercise. This is because in people with a hidden heart problem, the strain of intense exercise can trigger a fatal abnormal heart rhythm.

Many of the heart problems that can lead to sudden cardiac death are first suspected because of changes seen on an electrocardiogram (ECG), which measures the electrical activity of the heart. But regular intense exercise can also affect the heart’s electrical activity. The problem is that it’s not always clear whether the ECG changes seen in athletes are harmless, caused by the healthy heart adapting to intense exercise, or whether they mean the athlete might have an underlying heart condition that puts them at risk of sudden cardiac death.

Detecting hidden heart disease in athletes

Until recently, doctors used a set of recommendations prepared in 2010 by an international group of experts to interpret ECG changes in athletes. But these guidelines were mostly based on findings in White Italian athletes.

This is important because researchers have found that ECG test findings can be different between athletes from different ethnic groups. ECG changes are six times more common in athletes of Black African or African Caribbean ethnic origin compared with other ethnic groups. But these changes could simply be the heart's normal response to large amounts of exercise.

Understanding differences related to ethnic background

It became increasingly clear that the 2010 guidelines were not appropriate to guide practice in Black athletes. So, with BHF funding, Professor Sanjay Sharma, Consultant Cardiologist at St George’s Hospital, London, investigated the heart health of a group of African Caribbean athletes to help design better guidelines to identify Black athletes who are at risk of sudden cardiac death.

Identifying athletes at risk of sudden cardiac death saves lives – because they can be sent for further heart tests to diagnose and treat an underlying condition. If the ECG indicates either a heart rhythm or heart muscle disorder, athletes will have further tests to make the diagnosis and to see whether there are specific treatments that could allow them to continue with competitive sport.

On the other hand, being able to recognise normal ECG changes is just as important. A “false positive” result – where an ECG test is interpreted as indicating an underlying heart problem when there isn’t one – can mean an athlete has to needlessly give up competitive sport, often ruining careers.

Professor Sharma’s work contributed to the development of new international recommendations for ECG interpretation in athletes in 2017 that have markedly improved the accuracy of ECG interpretation in Black athletes. When tested among African American professional basketball players, the 2017 international recommendations lowered the false-positive rates from 40 per cent (using the 2010 thresholds) to almost 15 per cent - a huge improvement.

This means that more athletes can now be reassured that they are safe to continue doing competitive exercise.

But there is still work to do. The team is currently following up a large group of Black athletes with abnormal ECGs to find out whether they will go on to develop a heart problem in the future. This will give even more information about which types of ECG changes could be signs of future problems.

First published 1 June 2021