Causes, Circumstances, and Potential Preventability of Cardiac Arrest in the Young

Insights From a State-wide Clinical and Forensic Registry

Elizabeth D. Paratz; Alexander van Heusden; Dominica Zentner; Natalie Morgan; Karen Smith; Tina Thompson; Paul James; Vanessa Connell; Andreas Pflaumer; Christopher Semsarian; Jodie Ingles; Sarah Parsons; Dion Stub; Andre La Gerche


Europace. 2022;24(12):1933-1941. 

In This Article

Abstract and Introduction


Aims: The causes, circumstances, and preventability of young sudden cardiac arrest remain uncertain.

Methods and Results: A prospective state-wide multi-source registry identified all out-of-hospital cardiac arrests (OHCAs) in 1–50 year olds in Victoria, Australia, from 2019 to 2021. Cases were adjudicated using hospital and forensic records, clinic assessments and interviews of survivors and family members. For confirmed cardiac causes of OHCA, circumstances and cardiac history were collected. National time-use data was used to contextualize circumstances. 1319 OHCAs were included. 725 (55.0%) cases had a cardiac aetiology of OHCA, with coronary disease (n = 314, 23.8%) the most common pathology. Drug toxicity (n = 226, 17.1%) was the most common non-cardiac cause of OHCA and the second-most common cause overall. OHCAs were most likely to occur in sleep (n = 233, 41.2%). However, when compared to the typical Australian day, OHCAs occurred disproportionately more commonly during exercise (9% of patients vs. 1.3% of typical day, P = 0.018) and less commonly while sedentary (39.6 vs. 54.6%, P = 0.047). 38.2% of patients had known standard modifiable cardiovascular risk factors. 77% of patients with a cardiac cause of OHCA had not reported cardiac symptoms nor been evaluated by a cardiologist prior to their OHCA.

Conclusion: Approximately half of OHCAs in the young have a cardiac cause, with coronary disease and drug toxicity dominant aetiologies. OHCAs disproportionately occur during exercise. Of patients with cardiac cause of OHCA, almost two-thirds have no standard modifiable cardiovascular risk factors, and more than three-quarters had no prior warning symptoms or interaction with a cardiologist.


Out-of-hospital cardiac arrest (OHCA) poses a heavy medical, economic, and psychological burden, responsible for approximately one-third of deaths in people aged under 50 years.[1,2] The ability to predict and ultimately prevent cardiac arrest has been described in contemporary European Society of Cardiology Guidelines as the 'philosopher's stone' of modern cardiology.[3]

The majority of OHCA registries collects high-quality data from ambulance services according to the standardized Utstein template,[4] but do not record subsequent information regarding the confirmed underlying cause of the OHCA, circumstances of OHCA, or individualized patient clinical histories and risk factors. Such details are essential for confirming which events are truly cardiac in nature, as well as identifying prevalence of risk factors and symptoms to support and underpin the design of targeted public health strategies. Indications from the few prior studies reporting population-based OHCA investigation show many appear to be due to non-cardiac causes, that OHCA during sleep is most common, and that the majority of OHCAs in the young occurs without prior warning symptoms.[5–9]

We utilized a prospective state-wide OHCA registry with comprehensive clinical adjudication across ambulance, hospital, forensic databases, and clinic-based interviews. We aimed to determine the proportion of OHCAs with an underlying cardiac cause. For patients with confirmed cardiac cause of OHCA, a time-use research methodology was used to objectively contextualize the circumstances of their OHCA. Cardiovascular risk factor burden and the presence of prior warning symptoms were also assessed.