Sudden cardiac arrest in relation to exercise

Abstract

Background: In predisposed individuals with a known or unknown cardiovascular disease, the risk of a sudden cardiac arrest is increased during and immediately after exercise. The most common postmortem diagnosis of exercise-related cardiac death in the young is Sudden Arrhythmic Death Syndrome (SADS). Aims: The aims of this thesis were to describe incidence, demographics, circumstances of resuscitation and prognosis among victims of exercise-related Out-of-Hospital Cardiac Arrest (OHCA). Furthermore, we aimed to describe the phenotype of SADS in the young. Methods: This thesis is based on observational studies with the use of national quality registers. The Swedish Registry of Cardiopulmonary Resuscitation (SRCR) was used to identify cases of OHCA and to describe circumstances of resuscitation. The registry of the Swedish National Board of Forensic Medicine, the Swedish Cause of Death Registry, the Swedish National Patient Registry, the Swedish Prescribed Drug Registry were used to identify cases of SADS and to describe their phenotype. Each case of SADS was assigned five population-based controls from Statistics Sweden. Results: The incidence rate of exercise-related OHCA in the general population in Sweden was 1.2 per 100.000 person years. The 30-day survival rate was significantly higher for exercise-related OHCA compared to non-exercise related. Survival rates were higher at sports arenas compared to outside arenas. Exercise-related OHCA was rare among females, however they had a much worse prognosis compared with males. Victims aged 0-35 years had the highest survival rates. Of all SCDs among 1-35 years-old, SADS accounted for 22%. A higher proportion av SADS victims experienced previous cardiac symptoms and were in contact with healthcare providers prior to death, as compared to controls. Conclusion: Victims of exercise-related OHCA have significantly higher survival rates compared to non-exercise-related OHCA, partly due to favorable circumstances of occurrence. Female victims of exercise-related OHCA have low survival rates, which indicates a need for increased knowledge and awareness of exercise-related SCA in females. SADS accounted for a lower proportion of SCDs in the young, compared to previous studies. Prior symptoms and contact with healthcare providers offer possibilities to identify individuals at risk of SADS.