The burden of sudden cardiac arrest in the setting of acute coronary syndrome.

Background: The incidence of sudden cardiac arrest (SCA) during acute coronary syndrome is somewhat unclear, since often subjects dying before the first healthcare contact are not included in the estimates. We aimed to investigate the complete incidence of SCA during ACS.

Methods: The study population consists of two cohorts. The first cohort includes 472 ACS patients from Northern Ostrobothnia, Finland from year 2016 and the second cohort 162 autopsy-verified SCD subjects (extrapolated) from the same region and year, whose death was attributable to coronary artery disease (CAD) and ACS. An extrapolation of SCA incidence during ACS was done by utilizing autopsy data and data from prior autopsy study on this sample.

Results: The overall incidence of SCA in the setting of ACS was 17.5%. The incidence of SCA was 20.6% in all ACS subjects without prior CAD diagnosis, and 25.4% in STEMI subjects without prior CAD diagnosis. In subjects with previously diagnosed CAD, the incidence of SCA was 10.9% in all ACS subjects and 16.1% in STEMI subjects. There was a statistically significant difference in the incidence of SCA between subjects with and without prior CAD diagnosis (p = 0.0052).

Conclusion: The inclusion of ACS-SCA subjects dying before the first emergency medical service (EMS) contact results in a higher and likely more accurate estimation of SCA during ACS. The incidence of SCA was higher among subjects without prior CAD diagnosis. The high mortality rate highlights the importance of early ACS detection to reduce the burden of CAD-related premature deaths.