Higher survival rates in exercise-related out-of-hospital cardiac arrests, compared to non-exercise-related - a study from the Swedish Register of Cardiopulmonary Resuscitation

Background Despite the positive effects of physical activity, the risk of sudden cardiac arrest is transiently increased during and immediately after exercise. The purpose of this study was to assess the incidence of exercise-related out-of-hospital cardiac arrest in the general population and to compare characteristics and prognosis of these cardiac arrests with non-exercise-related out-of-hospital cardiac arrests. Methods Data from all cases of treated out-of-hospital cardiac arrest outside of home reported to the Swedish Register of Cardiopulmonary Resuscitation from 2011-2015 in three counties of Sweden were investigated (population 2.1m). This registry captures almost 100% of all out-of-hospital cardiac arrests in Sweden. Results Of 1825 out-of hospital cardiac arrests, 137 (7.5%) were exercise-related, resulting in an incidence of 1.2 per 100,000 person-years. The 30-day survival rate was significantly higher among exercise-related out-of hospital cardiac arrests compared to non-exercise-related out-of-hospital cardiac arrests (54.3 % vs 19.4%, p<0.0001). Patients suffering an exercise-related out-of-hospital cardiac arrest were on average 10 years younger than those who had a non-exercise-related out-of-hospital cardiac arrest, 56.4 years compared to 67.2 years. Exercise-related out-of-hospital cardiac arrests were more often witnessed (89.4% vs 78.6%, p=0.002), had higher rates of bystander cardiopulmonary resuscitation (80.3% vs 61.0%, p<0.0001) and were more frequently connected to an automated external defibrillator (20.4% vs 4.6%, p<0.0001). Conclusions Cardiac arrests that occur in relation to exercise have a significantly better prognosis and outcome than non-exercise-related cardiac arrests. This may be explained by favourable circumstances but may also reflect that these persons experience a sudden cardiac arrest at a lower degree of coronary artery disease, due to their younger age and to exercise being a trigger.