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Published On: October 27th, 2020By Categories: Public Health

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COVID-19 is known as an illness of the respiratory system, but the cardiovascular system has emerged as a critical player in the disease. Pre-existing cardiovascular conditions are linked with higher rates of mortality, and the virus can damage the cardiovascular system, causing potentially long-term injury.

Despite the known link between SARS-CoV2 infection and cardiovascular disease, the early phase of the pandemic was marked with significant decreases in the number of people suffering heart attacks in many of the world’s hotspots. The reduction in caseload has puzzled cardiologists for some time, but a study led by Dr. Patricia Lai from the Fire Department of the City of New York provides a possible answer1.

Cardiac Arrest in New York City

The study by Lai and colleagues compared the number of out of hospital cardiac arrests (OHCA) in New York City between March 1 through April 25, 2019 and March 1 through April 25, 20201. These dates were selected as March 1, 2020 was the day of the first COVID-19 diagnosis in New York City, and April 25, 2020 was when EMS calls neared the pre-COVID-19 volume of cases.

In 2020 there were 2,653 more OHCA calls to EMS compared to the same period in 2019. This represents an incidence of OHCA that was 3-times higher during the COVID-19 pandemic. In 2020, patients were older and less likely to be white than those seen in 2019. Patients were also more likely to have hypertension, diabetes or physical limitations such as being in a wheelchair in 2020. In addition to a higher rate of OHCA calls, there was an increase in OHCA deaths during the height of the COVID-19 pandemic in New York City, as compared to the same period in 2019. In 2019 approximately 25% of patients who suffered a cardiac arrest outside of the hospital recovered, compared to only 10% in 2020.

The study by Lai and others shows that the rates of cardiac arrest did not actually decline during the COVID-19 pandemic: they simply failed to show up in emergency departments and died outside of the hospital.

Out of Hospital Cardiac Arrest: A Global Problem

The trend of increased OHCA reported by Lai and colleagues was not unique to New York City. A French study led by Professor Eloi Marijon found the weekly incidence of OHCA doubled during the first month of the COVID-19 pandemic, along with significant declines in bystander CPR and higher rates of patients dead on arrival at hospital2. In Italy, Dr. Enrico Baldi and associates conducted a similar study of 4 regions in Italy and found an overall increased in OHCA of 52% and a significant increase in out of hospital deaths3.

COVID-19 and the Heart

Although it has been clearly established that COVID-19 can impact the heart and result in cardiovascular disease and injury, the mechanisms that causes damage to the heart is less frequently discussed. Throughout the phases of viral infection the heart can be injured by the inflammatory processes that are activated to fight off the virus4. Patients can also experience cardiac stress due to respiratory failure and low blood oxygen levels (hypoxemia). Any or all of these changes induced by COVID-19 or other viruses can damage the heart and increase the risk of having a heart attack4.

Treatment Hesitancy & Socioeconomic Factors

Once the mystery of the missing heart attacks was solved, researchers turned to investigating why patients who suffered a heart attack failed to reach the hospital. One explanation for the rise in OHCAs was a hesitancy to go to the hospital, especially among patients at high risk of dying from COVID-19. In support of this idea, Lai and colleagues1 found that those who suffered OHCA were more likely to have characteristics and conditions that were consistent with individuals at high risk for COVID-19 mortality: older, non-white men with pre-existing health issues.

A study by Baum and Schwartz found evidence that patients avoided care for non-COVID-19 conditions during the pandemic. They looked at 6 common emergency conditions and the caseload before and during the pandemic. In addition to a decrease in admissions for cardiovascular conditions, they reported that emergency cases for non-COVID-19 pulmonary conditions and appendicitis were reduced during the pandemic. From these data they concluded that patients were likely avoiding hospital treatment to reduce their risk of SARS-CoV2 infection5.

Along with the fear of infection, socioeconomic status impacts whether or not patients seek medical treatment1. Blacks, Hispanics, and Asians had higher rates of OHCAs compared to their White counterparts1. These increased rates may be because a large portion of communities of colour do not have adequate health insurance in the United States, which contributes to a delay in seeking treatment6. The risk of OHCA associated with COVID-19 for people with insufficient economic means is also elevated because they are more likely to live in an overcrowded environment and are often unable to telework, both which increase their risk of exposure to the virus1.

Emergency Response Time

In cardiology the phrase “time is muscle” is often used to emphasize the importance of a rapid response, which is necessary to protect the heart muscle against irreversible and potentially fatal damage. In New York City the increase in EMS calls during the early stage of the pandemic delayed the average emergency response time by 1 minute1. With a faster response time, patients are more likely to have a return of cardiac activity, but in the cases in New York City the delay was likely too small to fully explain the increase in deaths from OHCAs1. By contrast the study by Baldi and colleagues3 in Italy had a much longer delay in emergency response time of 3 minutes. Both the French2 and Italian3 studies suggest the slower emergency response times likely increased the rate of OHCA mortality.

Follow the Guidelines!

For many the focus during this pandemic is the number of deaths caused by COVID-19. However, with a global mortality rate of less than 3%7 and the mistaken belief that only the elderly and those with chronic health conditions are at risk, some people have stopped following recommended guidelines for preventative measure like social distancing and mask wearing.

Unfortunately, if these guidelines are not followed more people will be infected with the novel coronavirus, putting added pressure on healthcare systems throughout the world. As a result, hospitals and emergency responders will be less able to effectively treat patients with non-COVID-19 related conditions, such as OHCA, resulting in increased deaths. These deaths won’t be counted in the COVID-19 tracking systems, but the link is real.

Following public health guidelines on COVID-19 is critical to reducing deaths from infection, decreasing the burden on already overwhelmed healthcare systems, and saving lives.


  • 1. Lai PH, Lancet EA, Weiden MD, et al. (2020) Characteristics Associated with Out-of-Hospital Cardiac Arrests and Resuscitations During the Novel Coronavirus Disease 2019 Pandemic in New York City. JAMA Cardiol. Jun 19, e202488. DOI: 10.1001/jamacardio.2020.2488.;10.1001/jamacardio.2020.2488
  • 2. Marijon E, Karam N, Jost D, et al. (2020). Out-of-hospital cardiac arrest during the COVID-19 pandemic in Paris, France: a population-based, observational study. Lancet Public Health. 5(8), e437-e443. DOI: 10.1016/S2468-2667(20)30117-1
  • 3. Baldi E, Sechi GM, Mare C, et al. (2020) COVID-19 kills at home: the close relationship between the epidemic and the increase of out-of-hospital cardiac arrests. Eur Heart J. 41(32), 3045-3054. DOI: 10.1093/eurheartj/ehaa508
  • 4. Akhmerov A, Marbán E. (2020) COVID-19 and the Heart. Circ Res. 126(10), 1443-1455. DOI:10.1161/CIRCRESAHA.120.317055
  • 5. Baum A, Schwartz MD. (2020) Admissions to Veterans Affairs Hospitals for Emergency Conditions During the COVID-19 Pandemic. JAMA. 324(1), 96-99. DOI: 10.1001/jama.2020.9972
  • 6. Haynes N, Cooper LA, Albert MA, Association of Black Cardiologists. (2020) At the Heart of the Matter: Unmasking and Addressing COVID-19’s Toll on Diverse Populations. Circulation. 142(2):105-107. DOI: 10.1161/CIRCULATIONAHA.120.048126
  • 7. Johns Hopkins Coronavirus Resource Center. (2020). Link here

Gurkiran Dhuga is a student of Biomedical Sciences at the University of Guelph and an Undergraduate Research Assistant. Glen Pyle, PhD is a Professor of Molecular Cardiology at the University of Guelph and an Associate Member of the IMPART Team Canada Investigator Network at Dalhousie Medicine.