Sudden cardiac arrest (SCA) in athletes during competitive sports is rare (incidence of 0.76 per 100,000 athlete-years) but devastating, with severe consequences potentially leading to death during sports. Structural or arrhythmogenic causes of SCA, recognised causes for such events, are uncommon among athletes, according to the analysis performed by Landry and colleagues (1). Survival rates after SCA are generally comparable between competitive and non-competitive athletes (43.8% versus 44.8%).
In this context, basic life support (BLS) with early defibrillation, consisting of bystander cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED), is the intervention most closely related to good resuscitation outcomes in the general population as in sports-related sudden cardiac arrest occurring during competition activities or recreational exercises. Moreover, several strategies are largely adopted to increase the frequency and effectiveness of bystander cardiopulmonary resuscitation, through constant update and simplification of existing techniques as well as innovative approaches such as virtual or augmented reality, with the final aim to generate the highest survival rates from out-of-hospital cardiac arrest.
Prior studies have evaluated the impact of BLS on survival in sports-related SCA, but differences exist in the magnitude of these findings while many studies were most likely not powered enough to clearly discriminate the impact on important outcomes such as mortality.
In this proposed systematic review and meta-analysis, Michell and and colleagues (2) evaluated the associations between basic life support (BLS) and survival after a sports-related SCA, conducting a comprehensive search of several databases from each database inception between 1976 and 31 July 2021, in any language which included Ovid MEDLINE(R), Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus.
In total, 28 non-randomised studies were included; among those articles, 9 were included in the analysis regarding bystander presence (988 patients); regarding bystander CPR, 23 studies were included (2523 patients); finally, regarding bystander AED use, 19 studies were included (1227 patients).
Patients’ mean age ranged from 10 to 64 years, percentage of male was 89% (85–93%), a shockable rhythm was present in 74% (65–82%) of patients. The primary outcome was survival at the longest follow up.
In this meta-analysis of 28 studies the results were that bystander presence, bystander CPR, and bystander AED use were associated with better outcome with large significant effect sizes, resulted in, respectively, 2-, 3-, and 5-times higher survival compared with cases without bystander presence, without bystander CPR, and without bystander AED use (which seems to have the best positive impact on survival).
The results highlight the importance of witness intervention and encourage countries to develop their first aid training policy and AED installation in sport settings. Although CPR can prolong the neurological viability of a patient in SCA for as long as ten minutes using chest compressions, CPR alone cannot restore a normal rhythm and defibrillation is required to regain heart function. Since defibrillation is the most effective treatment for SCA, the longer a patient has to wait for a defibrillation shock, the lower the chances of survival.
In my opinion, this study clearly underlines the positive impact of an early AED, used by bystanders, on survival rates (OR 5.25; 95% CI: 3.58-7.70) in sports-related SCA.
In this context, the European Society of Cardiology (ESC) has recently published specific guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death (3), promoting a community training to increase bystander CPR and AED use, thus recommending the placement of automated external defibrillators (AEDs) in public areas, where cardiac arrests can occur, to allow a rapid starting of CPR by bystanders. Moreover, the American Heart Association/American College of Cardiology (AHA/ACC) guidelines for competitive sports (4) recommend that all schools and other organisations hosting athletic events, or providing training facilities for organised competitive athletic programmes, should have an emergency action plan that incorporates BLS and AED use.
Overall, recent ESC and AHA/ACC guidelines highlight a strong need for policies to increase both availability of AED and public awareness through community training in CPR and AED. The pre-participation screening of athletes should also include a baseline clinical evaluation to address cardiovascular risk, to minimise as much as possible the occurrence of SCA in this peculiar population.