Immediate Bystander Response to Sudden Cardiac Arrest During Sports is Associated with Improved Survival-- A Video Analysis


 Background Sudden cardiac arrest (SCA) during sports can be the first symptom of yet undetected cardiovascular conditions. Immediate chest compressions and early defibrillation offer SCA victims the best chance of survival, which requires prompt bystander response.Aims To determine the effect of rapid bystander response to SCA during sports by searching for and analyzing videos of these SCA/SCD events from the internet.Methods We searched images.google.com, video.google.com and YouTube.com, and included any camera-witnessed non-traumatic SCA in athletes and other sports participants at any sports facility. The rapidity of starting bystander chest compressions and defibrillation was classified as <3, 3-5, or >5 minutes. The year SCA occurred was allocated to 1990-2009, 2010-2014 or 2015 onwards, compatible with the current guidelines.ResultsWe identified and included 28 victims of average age 27.9 years (SD=9.8); 27 were males, 22 elite athletes, and 17 participated in soccer. Bystander response <3 minutes (6/28) or 3-5 minutes (1/28) and defibrillation <3 minutes was associated with 100% survival. Not performing chest compressions and defibrillation was associated with death (14/28), and >5 minutes delay of intervention with worse outcome (death 4/28, severe neurologic dysfunction 1/28). Survival was highest between 2010-2014 (71.4%).ConclusionsAnalysis of internet videos showed that immediate bystander response to non-traumatic SCA during sports was associated with improved survival. This suggests that immediate chest compressions and early defibrillation are crucially important in SCA during sport, as they are in other settings. Optimal use of both will most likely result in survival. The observed bystander responses to SCA during sports do not show awareness of current guidelines.

Immediate chest compressions and early de brillation are crucially important in SCA during sports, as they are in other settings. Optimal use of both will most likely result in survival.
Bystander responses to SCA during sports do not show awareness of current guidelines.

Background
Sudden cardiac arrest (SCA) during sports in otherwise healthy athletes is a rare and unexpected event with disastrous consequences, including sudden cardiac death (SCD). Athletes have a role model for the community, and resuscitation of athletes is an example for the society, as a result of which SCA usually receives a lot of media attention. Published media reports typically relate to pre-competition screening and cardiopulmonary resuscitation (CPR).

Aim
In this study we set out to analyze the rapidity of bystander response to non-traumatic SCA and outcomes during sports by searching for and analyzing videos of these SCA/SCD events from the internet.

Study design
We searched on images.google.com, video.google.com and YouTube.com for available videos using the keywords 'sudden cardiac arrest athlete', 'sudden cardiac death athlete' and 'resuscitation athlete'. We included any camera-witnessed non-traumatic SCA that occurred in athletes and other sports participants during or shortly after sports participation at any sports facility, by any age, gender, type and level of sports, that occurred after 1990. Exclusion criteria were traumatic SCA (bodily collision, accident), spontaneous recovery from collapse <2 minutes, implantable cardioverter de brillator (ICD) carrier, and videos inappropriate for assessment.
Next, we searched on google.com using each victim's personal name, 'cause of cardiac arrest' or 'cause of death' as keywords to determine the cause of SCA and survival. This included news reports posted on the internet. We did not review medical records of the victim involved. All data of each victim were anonymized for analysis.
Four observers (NB, PD, LH, MM) collected the obtained videos. The observers were grouped into two pairs to evaluate the included videos. A fth independent observer (NP) analyzed all obtained and included videos, blinded to the results of the two pairs of observers. Disagreement between the two pairs and the fth observer was resolved by consensus.
We determined each victim's baseline characteristics, such as age, sex, ethnicity, type of sports, level of sports, year and country of event. To determine recognition of SCA from the videos, we evaluated for each victim the physical activity immediately before onset of SCA, the mode of collapse during SCA onset, the appearance during on-going SCA (body position, movements, facial expression), and the nature and rapidity of bystander responses to SCA.
To determine the main purpose of our study the rapidity of bystander response, we assessed the time from SCA onset to starting chest compressions and from SCA onset to de brillation using a stopwatch.
Time was measured in minutes and seconds. When the exact time period could not be measured, but was beyond 5 minutes, the victim was included in our analysis and their time indicated as >5 minutes. We classi ed the rapidity of bystander response as <3, 3-5 or >5 minutes. The year in which SCA occurred was categorized towards 1990-2009, 2010-2014, or 2015 onwards, compatible with the periods of several published guidelines.

De nitions
We de ned 'athlete' as an individual who participates in an organized team or individual sports competing against others on a regular basis aiming to improve skills, excellence and athletic achievements. This includes high-school and collegiate sports . 'Elite athlete' is an athlete who competes at the highest level of national and international competition. 'Recreational sports participant' is an individual performing leisure-time activity. 'Victim' is any athlete, elite-athlete and recreational sports participant suffering SCA.

Statistical analysis
Descriptive statistics of continuous variables were presented with means and standard deviation (SD) and by median values and interquartile ranges (IQR) for non-normal distributed variables. Categorical variables were presented with the number of patients and percentages. We conducted the statistical analyzes using the SPSS package version 26.0 (SPSS® Inc., Chicago, IL, USA).

Results
In total, we identi ed and included 28 victims with camera-witnessed non-traumatic SCA during sports in our analysis ( Figure 1). Individual summaries of each victim are shown in Table 1.  Medical and paramedical personnel performed chest compressions in 9/28 victims (32.1%) and de brillation in 7/28 (25%). Referees did not perform chest compressions in any of the videos analyzed.

Discussion
Our analysis of the internet videos of 28 victims showed that immediate bystander response to nontraumatic SCA during sports was associated with improved survival. This suggests that immediate chest compressions and de brillation within three minutes are crucially important in SCA at sports facilities, and will most likely result in survival. Almost all SCA victims caught on video were elite athletes, with an organized medical team and emergency equipment including AED for immediate chest compressions and de brillation on-site. Although the numbers are small, we observed that survival improved after the introduction of the CPR guidelines in 2010, but declined after the updated guidelines of 2015 were published. This indicates that bystanders are not aware of current CPR guidelines.
The rst important question is why to date athletes still die at the sports facility? SCA may occur in every individual and is the leading cause of death in sport. [11] Survival from SCA is determined by early recognition, immediate bystander chest compressions and early de brillation without any hesitation. In this study, it appears that bystanders do not always recognize SCA. Viskin et al. reported in a similar camera-witnessed study of 23 traumatic or non-traumatic SCA and 6 sudden collapses in athletes during sport that bystanders failed to recognize SCA and tried to open the airway without performing chest compressions in 72.4%. [26] In our study this was 21.4%. Contrary to Viskin et al., we included nontraumatic SCA only to exclude external factors causing SCA, such as blunt chest trauma that may induce asystole or VT/VF depending on the timing of the cardiac cycle in which the impact occurred.
[27] In a previous study, we used the same method as we did in this study for video analysis in six elite athletes suffering non-traumatic SCA during sports . [17] We observed that an unexpected sudden loss of the upright position, loss of normal breathing, and a xed gaze were manifest in all six victims during the initiation of syncope. [17] In this study of 28 victims, the xed gaze was observed in 60.7%. Recognizing the lethal situation of SCA is an important topic in CPR and AED training for medical and paramedical personnel, team staff and referees. [11,19] Although referees are included in CPR training programs, we did not observe that referees who are nearby to a victim (especially in soccer) performed chest compressions. Nevertheless, if an athlete suddenly collapses during sports for no apparent reason and is unresponsive and not breathing normally, bystanders should perform CPR immediately without any hesitation or delay in starting chest compressions. [21] One bystander should start chest compressions, whilst others fetch an AED and apply it and sending for the emergency medical services (EMS) (911 US,

EU). Bystanders should follow the instructions given by the AED concerning chest compressions, analysis of the cardiac rhythm and de brillation.[15]
AEDs can be life-saving as is demonstrated by a Swedish (n=474) and a Dutch study (n=320). [28,29] Both studies observed that survival from out-of-hospital cardiac arrest if AED was used were 70% and 52%, respectively. [28,29] However, if bystanders performing CPR were interrupted by EMS paramedics or the application of the next AED shock was delayed, survival was reduced. [29] Drezner et al. demonstrated in a two-year prospective study in 2,149 American high schools equipped with an AED, that on-site de brillation within 3.5 minutes was associated with a survival of 89% (42/59 athletes). [6] Of the included 59 SCA events, 54 were witnessed, AED was applied in 50 victims, and 39 of them received de brillation. [6] Bohm et al. reported from a prospective German registry of SCA during sports (n=144) a survival rate of 26.4%. [9] The authors found that immediate bystander CPR was performed in 82%, and 40.7% had a shockable rhythm. [9] The survival rate in the German study among predominantly male middle-aged sports participants was lower than in the Swedish and Dutch studies among the general population. [9,28,29] The remaining question is why there was such a de brillation delay of beyond ve minutes? It is widely accepted that de brillation within 3-5 minutes increases survival (50-70%).
[15] Compatible with the related CPR guidelines, the survival in our study was highest between 2010-2014 (71.4%), but has not further increased or sustained from 2015 onwards (35.7%). In that recent period bystander response was delayed or not performed at all, demonstrating that the current guidelines have not been translated into improved rapid initiation of chest compressions and de brillation at sports facilities. Although our study popultion is small, this should raise concerns with guideline committees and CPR trainers for EMS paramedics, physicians and other personnel witnessing athletic activities in being trained for basic life support (BLS) and AED. [14][15][16]18] In a French registry of exercise-related SCA (n=820), the authors observed delay of AED arrival (beyond six minutes) to indoor-and outdoor-sports facilities, and infrequent use of an AED (<1%). [7] They reported higher survival in indoor-sports facilities (23%) than in outdoor-sports facilities (8%). [7] In addition it was noted that not performing or delaying AED shocks explained low survival.
in a similar study reviewing 26/35 videos of traumatic and non-traumatic SCA and arrhythmia-collapse in athletes, Steinkog et al. reported an association between very rapid bystander response and high survival (100%). [30] Also, a favorable association between de brillation within one minute and survival (n=12, 92%) was observed. [30] In our study with different inclusion criteria, we found an important association between immediate chest compressions and de brillation within three minutes and 100% survival in 7 victims (25%).
Athletic activities are often witnessed by many spectators, and therefore if SCA occurs there are more bystanders present to respond to SCA. However, it is di cult to explain that sometimes bystanders hesitate or delay immediate chest compressions and de brillation and that other bystander do not take their responsibility to start chest compressions. AEDs are recommended to be available on-site during athletic events and laymen are allowed to use them. [14,18,19,21] In the FIFA 11 steps to prevent SCD in soccer, FIFA recommend to put a medical emergency bag with an AED in position besides the eld-of-play and checked it before each professional soccer match. [11] In addition, in case of SCA the AED should be retrieved, applied and used as soon as possible. [11] Unfortunately, even to date a rapid emergency action sometimes fails.
Another avoidable (or unavoidable) delay is an emotional blockade of the bystander to initiate chest compressions and de brillation. Wik et al. analyzed the quality of CPR in 176 out-of-hospital advanced cardiac life supports procedures in the general population. [31] The authors found that bystanders, highlytrained paramedics and a anesthetist, failed to perform chest compressions in 48% of cases, probably because of an emotional blockade to perform CPR. [31] In our study, many bystanders were on the professional athletic team and therefore had a more personal relationship with the victim. It could be possible that some bystanders had an emotional blockade to initiate chest compressions and de brillation. Furthermore, it seemed that medical professionals performing CPR at sports facilities did not follow the BLS/AED algorithm, which also implies substantial room for improvement. [15,16,32] In our study, most athletes participated in commonly lmed elite sports, such as soccer. However, it does not re ect the risk of SCA in soccer compared to other sports. We found no camera-witnessed SCA in other popular sports, such as marathon running. During mass events with thousands of participants, the chance of capturing SCA on video is extremely small. Nevertheless, it is unacceptable that athletes still die during sports and that despite BLS/AED training and the availability of AED on-site, bystander response to SCA is delayed or absent. Our data strongly suggest that more SCA victims survive if bystander response is rapid and any delay in starting chest compressions and de brillation is avoided.

Strengths and limitations
The included videos were posted by television stations, athletic organizations and individuals recording SCA and CPR. Therefore, the information is selected and heterogeneous. Nevertheless, it is relevant and valuable. The main advantage of the camera-witnessed analysis was to objectively review victims' behavior before, at the onset and during SCA, and most importantly the rapidity of bystander response to SCA. We did not try to assess the quality of bystander CPR. The technical aspects of CPR, such as the depth and rate of chest compressions, de brillation, and ventilation were beyond the scope of our study.
In some victims the exact time to chest compressions and de brillation could not be measured and was set at >5 minutes. Survival improved if chest compressions was performed within ve minutes. Therefore, we included these >5 minutes results in our analysis.
Our collection of victims was limited to those uploaded on the Internet, thereby introducing selection bias.
We excluded traumatic SCA including bodily collision from our study. However, it could be possible that we may have missed commotio cordis as a cause of SCA.
Our cohort is not a representative sample of SCA occurring during sports . Most included victims were elite athletes competing in popular sports like soccer, especially in Europe. Other sports participants were underrepresented in our study. Notwithstanding these limitations and small numbers, our study suggests that more work is needed to improve the recognition and response to SCA during sport.

Future directions
To improve early recognition of SCA immediately followed by chest compressions and de brillation without any hesitation we propose that everyone involved in sports events is encouraged to attend BLS/AED training, thereby increasing SCA awareness and BLS/AED familiarity. This applies to teammates, coaching staff, referees and jury members, and especially supporting medical and paramedical professionals. Referees and jury are part of the competition and are nearest to a potential victim. Finally, as suggested in the literature, CPR training programs should also address the mental status of bystanders, including medical and paramedical professionals, to ensure adequate emergency action during the stressful circumstances of SCA. This can be done by inclusive training of the whole team -or of all match o cials -to try to eliminate 'human factors' and promote working as a team to support each other in responding promptly and appropriately to a victim in SCA.

Conclusions
Analysis of internet videos showed that immediate bystander response to non-traumatic SCA during sports was associated with improved survival. This suggests that immediate chest compressions and early de brillation are crucially important in SCA during sport, as they are in other settings. Optimal use of both will most likely result in survival. Bystander responses to SCA during sports do not always show awareness of current guidelines.

Declarations
Ethics approval and consent to participate We performed an Internet search, an open access medium, but we did not include a review of medical records, nor tested or treated the included individuals. Therefore, medical ethical approval was not mandated. In addition, all victim's data were anonymized, as mentioned in Methods, and all references related to the victim ,potentially identifying them, were not mentioned in this paper. The latter is added to the legends of Table 1. Therefore, we did not violate privacy regulations.

Consent for publication
No consent for publication required Availability of data and material In Methods we mentioned that 'All victim's data were anonymized for analysis' to protect the victim's privacy, we mentioned in the Legend of Table 1 'Note: References of the videos/images are not displayed due to privacy regulations'. As we do not want to violate the privacy regulations, we decided not to mention the references of the Internet sides displaying the videos. The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Competing interests
The authors declare that they have no competing interests.

Funding
No external funding was obtained.

Figure 1
Bystander response to camera-witnessed non-traumatic sudden cardiac arrest in athletes during sports Legends: SCA sudden cardiac arrest; ICD implantable cardio de brillator