How did you conduct your study?
This study sought to investigate the incidence and causes of sudden cardiac death in adolescent football players in the UK. The English Football Association cardiac screening programme enabled us to study a well-defined population of over 11,000 scholar footballers in a systematic way.
The study itself was conducted across three sites: St. George’s University of London, Wembley stadium and St. George’s Park in Burton-on-Trent. Between 1996 and 2016, we evaluated 11,168 adolescent athletes aged 16 years, the vast majority of whom were males (95%). They had all undergone cardiac screening with a health questionnaire, physical examination, ECG and echocardiogram. We were not only able to report the number of conditions identified but also the number of sudden cardiac deaths that ensued, which were confirmed with autopsy reports.
The main findings of the study were:
– During screening, 42 (0.38%) athletes were found to have cardiac disorders associated with sudden cardiac death. A further 225 (2%) minor cases of congenital and valvular abnormalities were identified.
– Following screening, there were 23 deaths from all causes, of which 8 (35%) were attributed to cardiac disease.
– Cardiomyopathies accounted for 7 (88%) sudden cardiac deaths.
– Six (75%) athletes who suffered sudden cardiac death demonstrated a normal cardiac screen at the age of 16 years.
– The mean time between screening and sudden cardiac death was 6.8 years.
– Based on a total of 118,351 person-years, the incidence of sudden cardiac death in previously screened adolescent soccer players was 1/14,794 person-years (6.8/100,000 athletes).
While 1 in 266 of the footballers having a condition may sound concerning, how much of this is due to a particularly high rate of Wolff-Parkinson-White syndrome in this group?
While a WPW ECG pattern accounted for the largest proportion of serious conditions among football players, the prevalence of a WPW pattern among our study population was 0.23% (26/11,168) which is similar to that reported in the general population which is between 0.1-0.3% (see reference).
(Ehtisham J, Watkins H. Is Wolff-Parkinson-White syndrome a genetic disease? J Cardiovasc Electrophysiol. 2005 Nov;16(11):1258-62.)
Does this research help confirm what we already knew, that athletes are more at risk than the general population?
The focus of the study was on the conditions identified that can are associated with exercise-induced sudden cardiac death. While all those who died did so during exercise, this is an association rather than causality, which is more difficult to prove without a control group of non-exercising individuals with a cardiac condition.
Seeing as 74% of those diagnosed with a condition were able to continue playing, can this research reassure other footballers and athletes?
The majority of these players consisted of those with WPW who underwent a curative procedure. Some with structural abnormalities such as anomalous coronary artery origins and valvular disease also underwent corrective operations and returned to play. This is encouraging for players who have been diagnosed with a condition in that this often does not signify the end of their sporting career.
How important is this research in reinforcing the value of cardiac screening, as it’s clear that all athletes need multiple screenings to ensure their safety?
Of the 42 cases identified in this study, only 2 experienced symptoms. Of the 8 deaths none were symptomatic. Therefore, some form of screening procedures need to exist to detect the vast majority of conditions associated with sudden cardiac death. Despite identifying 42 cases, this study shows that some athletes who are predisposed to developing cardiomyopathy in the future will not be identified at 16 years of age. Therefore, serial evaluations are advised.
Can this research help put better preventative measurements in place, with the FA making a proactive commitment to improve the rates of cardiac screening?
In 86% of all serious diseases identified, the ECG was abnormal. This suggests that screening should be implemented not just across the upper echelons of football, but potentially across grassroots football.
We should also highlight that screening is not a substitute for emergency response facilities, including AED provision and usage. Our group recently showed that emergency response facilities including primary and secondary prevention strategies across professional football clubs in England (see reference) was of a higher standard when compared with European counterparts. Training staff and ensuring AEDs are maintained are crucial in ensuring safety of athletes on the pitch too
(Malhotra A, Dhutia H, Gati S, Yeo TJ, Finocchiaro G, Keteepe-Arachi T, Richards T, Walker M, Birt R, Stuckey D, Robinson L, Tome M, Beasley I, Papadakis M, Sharma S. Br J Sports Med. 2017 Jun 14. pii: bjsports-2016-097440.)
What research needs to be carried out next to further these findings?
There are a number of avenues to explore based on the findings of this study. There was a 6-fold higher incidence of sudden cardiac arrest among black footballers compared to white footballers. Although there were many more white (90%) than black subjects, this corroborates with findings in the USA among black basketball players. The reasons behind this ethnic variation should be explored further.
The paper also highlighted over 250 athletes with abnormal ECG findings but a structurally normal heart. Reevaluation of these athletes will help further our understanding as to how many of these may have developed a cardiomyopathy.
Finally, longitudinal prospective serial evaluation of footballers will help shed light onto the issue of if and when a cardiomyopathy may manifest. The FA recommendations of an ECG at 18, 20 and 25 years of age, following an ECG and echo at 16 years, will provide data to help investigate this.