With the occurrences of the recent “high profile” sudden cardiac arrest in the news, it made me think “what exactly is really going on?”
I stated “high profile” because if it wasn’t for a celebrity, or known sports figure, no one would have ever known about the other over 300,000 others that have suffered a sudden cardiac arrest or similar heart related issue per year.
So what exactly is sudden cardiac arrest and what makes it so different from a heart attack or a stroke.
According to the Mayo Clinic, a sudden cardiac arrest is the abrupt loss of heart function, breathing and consciousness. The condition usually results from a problem with your heart’s electrical system, which disrupts your heart’s pumping action and stops blood flow to your body.
Sudden cardiac arrest isn’t the same as a heart attack, when blood flow to a part of the heart is blocked. However, a heart attack can sometimes trigger an electrical disturbance that leads to sudden cardiac arrest.
If not treated immediately, sudden cardiac arrest can lead to death. Survival is possible with fast, appropriate medical care. Cardiopulmonary resuscitation (CPR), using a defibrillator — or even just giving compressions to the chest — can improve the chances of survival until emergency workers arrive.
The signs of sudden cardiac arrest are immediate and drastic and include:
- Sudden collapse
- No pulse
- No breathing
- Loss of consciousness
Sometimes other signs and symptoms occur before sudden cardiac arrest. These might include:
- Chest discomfort
- Shortness of breath
- Fast-beating, fluttering or pounding heart (palpitations)
The usual cause of sudden cardiac arrest is an abnormal heart rhythm (arrhythmia), which happens when your heart’s electrical system isn’t working correctly.
The heart’s electrical system controls the rate and rhythm of your heartbeat. If something goes wrong, your heart can beat too fast, too slowly or irregularly (arrhythmia). Often these arrhythmia’s are brief and harmless, but some types can lead to sudden cardiac arrest.
The most common heart rhythm at the time of cardiac arrest is an arrhythmia in a lower chamber of your heart (ventricle). Rapid, erratic electrical impulses cause your ventricles to quiver uselessly instead of pumping blood (ventricle fibrillation).
The American Heart Association has released Heart and Stroke Statistics – 2022 Update. According to the report, cardiac arrest remains a public health crisis. There are more than 356,000 out-of-hospital cardiac arrests (OHCA) annually in the U.S., nearly 90% of them fatal. The incidence of EMS-assessed non-traumatic OHCA in people of any age is estimated to be 356,461, or nearly 1,000 people each day. Survival to hospital discharge after EMS-treated cardiac arrest languishes at about 10%.
There are several ongoing challenges to understanding the epidemiology of cardiac arrest in the U.S. Despite being a leading cause of death there are currently no nationwide standards for surveillance to monitor the incidence and outcomes of cardiac arrest. Thus, registries and clinical trials are used to provide best estimates. These sources include the Resuscitation Outcomes Consortium (ROC), 2005-2015, and the ongoing Cardiac Arrest Registry to Enhance Survival (CARES).
OHCA incidence: Adults
The incidence of EMS-assessed OHCA in 2015 was 347,322 based on extrapolation of ROC data.
Based on CARES data, in 2020 the location of OHCA in adults was most often a home or residence (73.9%), followed by public settings (15.1%), and nursing homes (10.9%).
OHCA was witnessed by a layperson in 37.1% of cases or by a 911-responder in 12.8% of cases. For 50.1% of cases, collapse was not witnessed.
OHCA incidence: Children
Based on ROC data, the incidence of EMS-assessed OHCA in children in 2015 was 7,037.
Based on CARES data, in 2020, the location of OHCA in children was most often home (87.5%), followed by a public place (12.2%).
Sports-related SCA accounted for 39% of SCAs among those <18 years of age, 13% for those 19-25 years of age, and 7% for those 25-34 in a prospective registry of 3,775 SCAs in Portland, OR between 2002-2015.
The incidence of SCD from Lexis Nexis and public media reports during youth sport participation, estimated by the Sport and Fitness Industry Association from 2007-2015, was 1.83 deaths per 10-million athlete years.
Pre-participation screening of 5,169 middle and high school students (mean age 13 years) from 2010-2017 revealed high-risk cardiovascular conditions in 1.47%.
The COVID pandemic had multiple effects on the incidence of OHCA.
In New York City, the incidence of OHCA attended by EMS (March 1-April 25, 2020) increased 3-fold, compared with the same period a year earlier.
Data from the CARES registry showed increased delays to initiation of CPR for OHCA and reduced survival after OHCA coinciding with timing of the pandemic. There was a reduction in the frequency of shockable rhythms, OHCA in public locations, and bystander AED use. Despite this, there was no significant alteration in frequency of bystander CPR.
Awareness and treatment
The prevalance of reported CPR training was 18% and having CPR training at some point was 65% in a survey of 9,022 people in the U.S. in 2015. The prevalence of CPR training was lower in Hispanic/Latino people, older people, people with less formal education, and lower-income groups.
Laypeople initiated CPR in 40.8% of OCHAs (CARES 2020 data). States with higher bystander CPR rates include Alaska (72%), California (41.8%), Hawaii (45.2%), Mississippi (42.4%), Montana (49.6%), Nebraska (49.1%), North Carolina (42.9%), Oregon (56%), Vermont (53.8%), and Washington (56.3%).
Laypeople were less likely to initiate CPR for people with OHCA in low-income Black neighborhoods or in predominately Hispanic neighborhoods than in high-income White neighborhoods.
Laypeople used AEDs in 5.8% of OHCAs and provided a shock in 1.3% of OHCAs (CARES 2011-2020 data).
Laypeople used AEDs in 9% of OCHA cases in 2020. States with higher rates of bystander AED use include Alaska (9.7%), Minnesota (9.4%), Nebraska (16.3%), North Carolina (9.5%), Oregon (13.5%), Pennsylvania (10.3%), Utah (9.5%), and Washington (10.9%).
OHCA outcomes: Adults
Survival to hospital discharge after EMS-treated OHCA was 9% and survival to hospital discharge with good functional status was 7%, based on 124,088 cases (CARES 2020). Note: the AHA previously reported that unadjusted survival to hospital discharge after EMS-treated OHCA increased from 10.2% in 2006 to 12.4% in 2015 in the ROC epistry.
Survival to hospital discharge after EMS-treated OHCA was higher in the Midwest and South, relative to the Northeast.
Survival and neurologic recovery after OHCA are worse in White Hispanic, Black, and Asian patients, compared with White patients. Disparities were explained only in part by delays in onset of medical care, suggesting there may be other underlying vulnerabilities.
OHCA outcomes: Children
Survival to hospital discharge after EMS-treated nontraumatic OHCA in 2015 was 13.2% for children in the ROC epistry.
Survival to hospital discharge was 6.5% for 1,366 children < 1 year of age, 14.4% for 880 children 1-12 years of age, and 21.2% for 736 children 13-18 years of age (CARES 2020).
OHCA outcomes: Sports-related SCA-SCD
In a population-based registry of all paramedic responses for SCA from 2009-2014, 43.8% of athletes with SCA during competitive sports survived to hospital discharge.
Survivors of cardiac arrest experience multiple medical problems including impaired consciousness and cognitive deficits.
Functional impairments are associated with reduced function, reduced quality of life, and shortened life span.
Functional recovery continues over at least the first 12 months after OHCA in children and over 6 to 12 months after OHCA in adults.
Serial testing in a cohort of 141 people who survived hospitalization after SCA revealed severe cognitive deficits (13%), anxiety and depression (15%), post traumatic stress symptoms (28%), and severe fatigue (52%). Subjective symptoms declined over time after SCA, although 10-22% had cognitive impairments at 12 months, with executive functioning being most affected. Of 141 individuals who survived hospitalization after SCA, 72% returned to work after 12 months.
Of 287 people who survived hospitalization after OHCA, 47% had reduced participation in pre-OHCA activities and 27% of those who were working before OHCA were on sick leave at 6 months.
Among 195 caregivers of cardiac arrest survivors, 25% experienced anxiety and 14% experienced depression at 12 months.