Exercise related versus non exercise related out of hospital cardiac arrest – A retrospective single-center study

• In this single-center study OHCA related to exercise had a favorable first line response compared to OHCA during daily activities leading to better survival to discharge. • 80.6% of the patients with OHCA related to exercise had a primary shockable rhythm and a cardiac cause of cardiac arrest. • Primary prevention in exercising individuals, increasing bystander CPR and AED distribution and treatment at dedicated cardiac arrest centers might further improve outcomes. Physical activity prevents cardiovascular disease, but it may also trigger acute cardiac events like sudden cardiac death in patients with underlying heart disease. The chance of surviving an out-of-hospital cardiac arrest remains low, despite improving medical treatment and rescue chain. Prior studies signaled increased survival in exercise related out-of-hospital cardiac arrest. The aim of this study was to evaluate the differences between exercise related out-of-hospital cardiac arrest and out-of-hospital cardiac arrest during daily activity in an urban setting. Retrospective analysis of all out-of-hospital cardiac arrests from 2014 to 2021 treated at a cardiac arrest center of a tertiary hospital. The primary outcome was survival to discharge. Secondary outcomes included differences in pre-hospital care, in-hospital treatment, hypoxic ischemic encephalopathy, and laboratory parameters. 478 OHCA patients were reviewed of which 432 patients (exercise related 36 (8.4%) vs. daily activity 396 (91.6%)) were included in the analysis. Patients suffering an exercise related arrest were younger (57 vs 65 years, p = 0.002) and mostly male (88.9 vs 74.5%, p = 0.054). The exercise related cohort received bystander cardiopulmonary resuscitation (77.8 vs 53.4%, p = 0.005) to a higher extent and had a shorter no-flow time (1.5 vs 2 min, p = 0.049). Exercise related arrest patients more often presented with a shockable rhythm (80.6 vs 64.1%, p = 0.032). At hospital admission exercise related arrest patients had a higher initial pH (7.24 vs 7.19, p = 0.015). In the exercise related group, a cardiac cause was numerically more frequent compared to the daily activity group (80.6 vs 68.7%, p = 0.09). In both groups myocardial infarction (47.2 vs 43.2%) was the most common cause, but a primary arrhythmic event (33.3 vs 25.5%) was more often documented in exercise related arrest patients. Exercise related arrest was mostly related to endurance training (52.8%) followed by ball sports (19.4%) and occurred directly during exercise in 77.8% of cases. Patients suffering exercise related arrest had higher survival till discharge (66.7 vs 47.7%, p = 0.036). Based on this observational data from a highly selected group of out-of-hospital cardiac arrest patients treated at a cardiac arrest center, patients suffering an exercise related out-of-hospital cardiac arrest, differed in substantial characteristics and in the first line response compared to daily activity out-of-hospital cardiac arrest patients. The better survival to discharge of the exercise related out-of-hospital cardiac arrest group might be driven by these beneficial differences. This study underlines the need for public awareness for the importance of a fast first response and a broad distribution of automated external defibrillators in public sport areas since most of the exercise related out-of-hospital cardiac arrest patients presented with a cardiac cause and an initial shockable rhythm.