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Factors Predisposing to Survival After Resuscitation for Sudden Cardiac Arrest
Santo Ricceri1, James W Salazar2, Andrew A Vu3
1Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA. Electronic address: https://twitter.com/SantoRicceri.
Insights
Sudden cardiac arrests (SCAs) that survive hospitalization are often caused by arrhythmias, unlike sudden cardiac deaths (SCDs). Identifying non-arrhythmic causes like neurologic emergencies may improve out-of-hospital cardiac arrest (OHCA) survival rates.
Area of Science:
- Cardiology
- Emergency Medicine
- Public Health
Background:
- Sudden cardiac death (SCD) studies often exclude resuscitated sudden cardiac arrests (SCAs).
- Previous research on SCDs found only 56% had an arrhythmic cause.
- The heterogeneity of causes in resuscitated SCAs was hypothesized but not fully explored.
Purpose of the Study:
- To determine the underlying causes of resuscitated out-of-hospital cardiac arrests (OHCAs).
- To analyze the outcomes and survival predictors for resuscitated SCAs.
- To compare the characteristics of resuscitated SCAs with WHO-defined SCDs.
Main Methods:
- Conducted a 4-year countywide study of out-of-hospital cardiac arrests (OHCAs) in San Francisco County.
- Identified patients aged 18-90 years meeting WHO criteria for suddenness and surviving to hospitalization.
- Determined underlying causes through comprehensive medical record review.
Main Results:
- Of 734 OHCAs, 133 met SCA criteria and were resuscitated to hospitalization; 47 survived to discharge.
- Arrhythmic causes were more prevalent in resuscitated SCAs (69.1%) and survivors (91.5%) compared to SCDs (55.8%).
- Arrhythmic cause, initial ventricular tachycardia/fibrillation, and white race predicted survival; neurologic causes did not.
Conclusions:
- Resuscitated SCAs are distinct from SCDs, with arrhythmias being a primary cause, especially in survivors.
- Non-arrhythmic causes, particularly neurologic emergencies, were associated with non-survival in OHCA.
- Targeting non-arrhythmic causes offers a potential strategy to improve OHCA survival rates.
Background:
In the POST SCD study, the authors autopsied all World Health Organization (WHO)-defined sudden cardiac deaths (SCDs) and found that only 56% had an arrhythmic cause; resuscitated sudden cardiac arrests (SCAs) were excluded because they did not die suddenly. They hypothesized that causes underlying resuscitated SCAs would be similarly heterogeneous.
Objectives:
The aim of this study was to determine the causes and outcomes of resuscitated SCAs.
Methods:
The authors identified all out-of-hospital cardiac arrests (OHCAs) from February 1, 2011, to January 1, 2015, of patients aged 18 to 90 years in San Francisco County. Resuscitated SCAs were OHCAs surviving to hospitalization and meeting WHO criteria for suddenness. Underlying cause was determined by comprehensive record review.
Results:
The authors identified 734 OHCAs over 48 months; 239 met SCA criteria, 133 (55.6%) were resuscitated to hospitalization, and 47 (19.7%) survived to discharge. Arrhythmic causes accounted for significantly more resuscitated SCAs overall (92 of 133, 69.1%), particularly among survivors (43 of 47, 91.5%), than WHO-defined SCDs in POST SCD (293 of 525, 55.8%; p < 0.004 for both). Among resuscitated SCAs, arrhythmic cause, ventricular tachycardia/fibrillation initial rhythm, and white race were independent predictors of survival. None of the resuscitated SCAs due to neurologic causes survived.
Conclusions:
In this 4-year countywide study of OHCAs, only one-third were sudden, of which one-half were resuscitated to hospitalization and 1 in 5 survived to discharge. Arrhythmic cause predicted survival and nearly one-half of nonsurvivors had nonarrhythmic causes, suggesting that SCA survivors are not equivalent to SCDs. Early identification of nonarrhythmic SCAs, such as neurologic emergencies, may be a target to improve OHCA survival.
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