Epidemiological aspects of cardiac arrest
Data sources for monitoring cardiac arrest and resuscitation
There are currently several large registries monitoring resuscitation practices. Some data sources also monitor sudden cardiac arrest. The EuReCA registry includes resuscitation data from 27 European nations and the Get With the Guidelines Resuscitation Investigators reports data from the United States. The varying inclusion criteria in these registries explain the marked differences in chacteristics and outcomes across the data sources for out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA).
Age and sex
The median age in OHCA is 70 years in Sweden, 66 years in Europe (EuReCA) and 65 years in the United States. No trends, with regard to age or sex, have been observed in Sweden between 1990 and 2021 (Rawshani et al).
Incidence of cardiac arrest
- Worldwide the incidence of out-of-hospital cardiac arrest ranges from 20 to 140 cases per 100,000 inhabitants (Ahern et al).
- In the United States more than 500,000 individuals (adults and children) experience a cardiac arrest (Heart Disease and Stroke Statistics). The CARES registry reported that the incidence was 92 per 100,000 citizens in the United States (Bagai et al).
- The incidence of treated cardiac arrests outside hospitals (OHCA) is about 70 cases per 100,000 person-years in Europe (EuReCA One, Benjamin et al).
- A total of 292,000 cases of IHCA occur annually in the United States, resulting in an incidence of 7 IHCAs per 1,000 hospital admissions (Merchant et al). The Danish cardiac arrest registry (DANARREST) reports 1,8 IHCAs per 1,000 hospital admissions (Andersson et al), and the UK National Cardiac Arrest Audit (NCAA) reports 1,6 IHCAs per 1000 hospital admissions (Nolan et al).
Survival in cardiac arrest
Survival in OHCA
Yan et al performed a meta-analysis and systematic review of 141 studies on the survival in treated OHCA. Pooling all the eligible studies resulted in the following survival estimates:
- Likelihood of return of spontaneous circulation (ROSC) was 29.7% (95% CI 27.6–31.7%)
- Likelihood of survival to hospital admission was 22.0% (95% CI 20.7–23.4%)
- Likelihood of 30-day survival was 10.7% (95% CI 9.1–13.3%)
- Likelihood of survival to hospital discharge was 8.8% (95% CI 8.2–9.4%)
- Likelihood of 1-year survival rate was 7.7% (95% CI 5.8–9.5%).
Survival in IHCA
- Survival in IHCA was 25% in 2006 and 35% in 2021 in Sweden (Jerkeman et al).
- Survival in the United States (GWTG-RI) was 25% in 2017.
Location and witnesses
- About 60% of all out-of-hospital cardiac arrests are witnessed, which is fundamental for survival.
- About 50% of all out-of-hospital cardiac arrests receive bystander CPR, which doubles the probability of survival (Nakahara et al, Hasselqvist-Ax et al).
- About 70% of all cardiac arrests occur in homes. These cases have substantially worse survival than cases occurring in public places, where there are people who can provide CPR, alert the ambulance and use a public defibrillator.
Survival in relation to initial rhythm
In cardiac arrest, the initial rhythm (on the first recorded ECG) is a very strong predictor of survival. This is because cardiac arrest presenting with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) can be defibrillated to restore an organized rhythm and thus mechanical cardiac function. These rhythms (VF, VT) are referred to as shockable rhythms.
Survival in OHCA in relation to initial rhythm
- If the initial rhythm is VF or VT, survival is 30% in OHCA.
- If the initial rhythm is PEA (pulseless electrical activity), survival is 5% in OHCA.
- If the initial rhythm is asystole, survival is 1% in OHCA.
Survival in IHCA in relation to initial rhythm
- If the initial rhythm is VF or VT, survival is 50–60% in IHCA.
- If the initial rhythm is PEA (pulseless electrical activity), survival is 10% in IHCA.
- If the initial rhythm is asystole, survival is 5% in IHCA.
Initial rhythm and EMS response times
It can be presumed that the majority of all cardiac arrests start with VF or VT, which gradually degenerate into PEA and asystole within minutes unless efficient CPR is provided. In 1990, it took an average of 5 minutes for the ambulance to arrive in an out-of-hospital cardiac arrest. The corresponding figure today is 11 minutes, which explains why the proportion exhibiting a shockable first rhythm has halved between 1990 and 2020. At present, about 25% of all out-of-hospital cardiac arrests exhibit a shockable initial rhythm, as compared with 50% in 1990. Another explanation for the halving in shockable rhythm is that the incidence of acute myocardial infarction has decreased dramatically in recent decades (Wallentin et al).
Cardiac arrest during sports and physical activity is more common among younger individuals. Among these, the proportion of witnessed cardiac arrest is naturally higher, the victims are usually healthier and the prognosis is better compared to OHCA in general. The most common forms of sport in cardiac arrest are jogging and cycling. Hypertrophic obstructive cardiomyopathy (HCM) is the most common cause of cardiac arrest among athletes (accounting for 30% of all cases). In addition, coronary artery anomalies (20%), myocarditis (7%), ARVC (5%), coronary heart disease (5%) and commotio cordis (3%) are also seen.
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Hasselqvist-Ax I, Riva G, Herlitz J, et al. Early cardiopulmonary resuscitation in out-of-hospital cardiac arrest. N Engl J Med 2015.
Nakahara S, Tomio J, Ichikawa M, et al. Association of bystander interventions with neurologically intact survival among patients with bystander-witnessed out-of-hospital cardiac arrest in Japan. JAMA IN 2015.
Ringh M, Rosenqvist M, Hollenberg J, et al. Mobile-phone dispatch of laypersons for CPR in out-of-hospital cardiac arrest. N Engl J Med 2015.
Rajan S, Folke F, Hansen SM, et al. Incidence and survival outcome according to heart rhythm during resuscitation attempt in out-of-hospital cardiac arrest patients with presumed cardiac etiology. Resuscitation 2017.
Buick JE, Drennan IR, Scales DC, et al. Improving temporal trends in survival and neurological outcomes after out-of-hospital cardiac arrest. Circ Cardiovasc Qual Outcomes 2018.
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Wallentin L. Cardiovascular Medicine in Sweden Improvement by Continuous Measuring. Circulation. 2020.
Ahern RM, Lozano R, Naghavi M, Foreman K, Gakidou E, Murray CJ. Improving the public health utility of global cardiovascular mortality data: the rise of ischemic heart disease. Popul Health Metr. 2011;9:8.
Bagai A, McNally BF, Al-Khatib SM, Myers JB, Kim S, Karlsson L, Torp-Pedersen C, Wissenberg M, van Diepen S, Fosbol EL, Monk L, Abella BS, Granger CB, Jollis JG. Temporal differences in out-of-hospital cardiac arrest incidence and survival. Circulation. 128(24):2595-602 (2013).
Crit Care Med. 2011 Nov;39(11):2401-6. doi: 10.1097/CCM.0b013e3182257459. Incidence of treated cardiac arrest in hospitalized patients in the United States Raina M Merchant 1, Lin Yang, Lance B Becker, Robert A Berg, Vinay Nadkarni, Graham Nichol, Brendan G Carr, Nandita Mitra, Steven M Bradley, Benjamin S Abella, Peter W Groeneveld; American Heart Association Get With The Guidelines-Resuscitation Investigators
Adult in-hospital cardiac arrest in Denmark Author links open overlay panelLars W. Andersen a b, Mathias J. Holmberg a, Bo Løfgren a c d, Hans Kirkegaard a, Asger Granfeldt https://doi.org/10.1016/j.resuscitation.2019.04.046
Incidence and outcome of in-hospital cardiac arrest in the United Kingdom National Cardiac Arrest Audit Jerry P. Nolan a, Jasmeet Soar b, Gary B. Smith c, Carl Gwinnutt d, Francesca Parrott e, Sarah Power e, David A. Harrison e, Edel Nixon e, Kathryn Rowan e, on behalf of the National Cardiac Arrest. https://doi.org/10.1016/j.resuscitation.2014.04.002