Elsevier

Resuscitation

Volume 144, November 2019, Pages 99-105
Resuscitation

Clinical paper
Exercise related sudden cardiac death (SCD) in the young — Pre-mortal characterization of a Swedish nationwide cohort, showing a decline in SCD among athletes

https://doi.org/10.1016/j.resuscitation.2019.09.022Get rights and content

Abstract

Aims

To study the frequency, etiology, and premortal abnormalities in exercise-related sudden cardiac death (SCD) in the young in Sweden.

Methods

All subjects with SCD in 10–35-year olds in Sweden during 2000–10, were included (n = 514). Information about each case was retrieved from death certifications, autopsy- and medical records. The number of SCD in athletes was compared to national figures from 1992-99.

Results

Exercise-related SCD occurred in 12% (62/514) of the SCD-population, a majority being men (56/62; 90%). Cardiopulmonary resuscitation (CPR) was started in 87% (54/62). In total, 48% (30/62), had a cardiac diagnosis, symptoms, family history and/or ECG-changes, before the fatal event. The most prevalent autopsy diagnosis was sudden arrhythmic death syndrome (15/62; 24%). The frequency of hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC) was significantly higher in exercise-related SCD compared to non-exertional SCD. Exercise-related SCD was more common in athletes (21/29) than in non-athletes (41/485) (P < 0.0001). The total number of SCDs/year in athletes 15–35 years old, are approximately halved in 2000-10 compared to the years 1992–99.

Conclusion

The increased risk of exercise-related SCD in HCM and ARVC underlines the importance of early detection and eligibility recommendations. There is a major reduction in deaths among athletes in the 2000s, compared to the previous decade. These results may partly be explained by improved acute preparedness for sudden cardiac arrest (CPR, defibrillation), but as a substantial percentage have preceding risk factors, such as symptoms and ECG-abnormalities, increased cardiac screening and increased general awareness, may also play a role.

Introduction

Sudden cardiac death (SCD) is uncommon, but accounts for a majority of natural, unexpected sudden death in the young population. Exercise, although clearly health promoting for the vast majority of individuals, is a well known potential trigger of SCD.1

In the Veneto region, athletes in 1979–80 had a four-fold increased risk of SCD compared to non-athletes.2 The incidence among athletes has then been decreasing in this region, generally attributed to the pre-participation screening of athletes, and in 2004 was lower, (0.4 per 100,000 per year), than the incidence among non-athletes, (1.0 per 100,000 per year).3 In the US, a prospective study from 2009–11, found a 3.6 times relative risk for sudden cardiac arrest (SCA) in high school athletes vs non-athletes.4 In Sweden, we have previously studied SCD in the young population 15–35 years.5, 6 Since the 1990’s focus has been increased on SCD in athletes, both nationally and internationally, with cardiac screening recommendations for athletes, being published by the European Society of Cardiology (ESC) in 20057 and by the Swedish National Federation of Sports 2005 and 2014.8 No follow-up of the incidence of SCD, since the introduction of such measures has been performed.

So far, SCD studies have commonly encompassed the risk of exertional SCD in competitive athletes, while reports on SCD during recreational sports activities are uncommon. This is important, since the borderline between competition and non-competitive sports is sometimes difficult. While competition offers an additional level of stress, training can be of very high intensity and duration, while, conversely, competitive athletes may be competing in non-exhaustive sports (bowling, chess). Gathering information about these deaths may be helpful in the planning of preventive strategies.

The aim of this study was to give an overview of all exercise related SCD in the young Swedish population during the 11-year period 2000–10, regarding the frequency, etiology, and prevalence of previous symptoms, family history and/or ECG-changes in this population. In addition, we aimed to compare the frequency of SCD in athletes in a well- defined national autopsy-based SCD cohort,9 with similar national data from the previous decade.6

Section snippets

Definitions

SCD was defined as a witnessed, natural, unexpected death from cardiac causes occurring within 1 h after onset of symptoms in an apparently healthy person, or an unwitnessed, natural, unexpected death of a person observed to be well within 24 h of being found dead.10 Subjects who initially survived sudden cardiac arrest (SCA) after cardiopulmonary resuscitation (CPR) and died more than one hour later after life-preserving measures were interrupted, were also included.

An athlete was defined as a

Exercise related sudden cardiac death

Cardiopulmonary resuscitation (CPR) was started in all witnessed cases (48/62; 77%), and in some unwitnessed cases when found (6/62; 10%). CPR was started by bystander in most cases (46/62; 74%) and continued by the ambulance crew. Ventricular fibrillation was seen in 34% (21/62) (Table 1). In five cases the victims initially survived after resuscitation, but died later in hospital.

Discussion

The main results of the present study were, that among all subjects 10–35 years old, suffering from SCD in Sweden 2000–10, 12% were exercise-related, and affected mainly men (90%). SADS was the most common etiology. Death during exercise was more common in athletes than in non-athletes (P < 0.0001). Specifically, exercise seemed to trigger SCD in men with ARVC and HCM. 48% of the subjects had a premortal risk profile, potentially detectable by recommended cardiac screening strategies.7 One

Conclusion

12% of SCD cases in the young Swedish population are exercise-related, with SADS being the most common etiology. The risk of exercise-related SCD is higher for athletes compared to non-athletes. Specifically, exercise seems to trigger SCD in men with ARVC and HCM. About 50% of the subjects have a pre-mortal risk profile, highlighting the possibility to detect these individuals prior to the fatal event, by cardiac screening. Importantly, the number of SCDs/year in young athletes has been

Conflict of interest statement

There is no conflict of interest.

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