Scientists have warned a cardiac arrest is “common” among critically ill coronavirus patients.
Although initially considered an infection of the airways, research has since linked severe cases to everything from chronic fatigue and hearing loss to temporary brain damage and type 1 diabetes in children.
Early research suggests four in five coronavirus incidences are mild, however, scientists have warned inflammation triggered by the infection could lead to cardiovascular complications.
Results revealed more than one in 10 (14%) of the critically ill participants had a cardiac arrest – when the heart stops beating – within 14 days of being admitted.
At the start of the outbreak, anecdotal reports emerged of critically ill coronavirus patients having cardiac arrests, prompting discussions on the futility of cardiopulmonary resuscitation (CPR).
A cardiac arrest means the heart cannot pump blood around the body, depriving the brain of oxygen. A patient typically loses consciousness within a few minutes and will die unless treated immediately.
Implementation of “do not attempt cardiopulmonary resuscitation” (DNACPR) policies amid the pandemic has been controversial, the Michigan scientists wrote in the BMJ.
Some have argued DNACPR should be considered when intensive care beds are limited or if a healthcare worker performing CPR would be at high risk of infection.
These arguments were made under the assumption of poor survival among patients with COVID-19 after an in-hospital cardiac arrest, however, “data to support this assumption were lacking”.
To help guide these discussions, the Michigan scientists analysed coronavirus patients aged 18 or over who were admitted to 68 hospitals.
Of the 5,019 participants, 701 (14%) had a cardiac arrest, of whom just over half (57%) received CPR.
Watch: The complications linked to severe COVID
The cardiac arrest patients tended to be older than the other participants, with an average age of 63 compared to 60.
They also had more underlying health conditions and were more likely to be admitted to a hospital with fewer intensive care beds.
This suggests hospital resources, staffing levels, healthcare worker expertise and the “strain” of working amid the pandemic “could have had a major impact” on a patient’s prognosis, according to the scientists.
Among the patients who received CPR, the average age was 61 compared to 67 for those who were not resuscitated.
The results further show only 12% of the CPR patients survived to hospital discharge and just 7% did so with normal or mildly impaired “neurological status”.
Due to the brain being starved of oxygen, cardiac arrest survivors can endure personality changes, involuntary movements or even permanent damage.
Survival among the participants differed by age, with just under a quarter (21%) of those younger than 45 making it compared to 3% of those aged 80 or over.
The scientists concluded: “Cardiac arrest is common in critically ill patients with COVID-19 and is associated with poor survival, particularly among older patients.
“Our study data could help inform patients, family members and clinicians in complex decision making about patients with COVID-19 who are at risk of cardiac arrest or who have experienced cardiac arrest.”
How could coronavirus affect the heart?
Viral infections are recognised as one of the most common causes of inflammation of the heart muscle, which reduces its ability to pump blood efficiently around the body.
Although unclear, the coronavirus may also replicate and spread through the blood and lymphatic system, entering the heart.
It can also trigger inflammation that damages the cardiovascular system.
Biomarkers have suggested a “high prevalence of cardiac injury” in patients hospitalised with the coronavirus.
“Many viruses can affect the heart muscle as well as the lining around the outside of the heart that lubricates the heart's movement,” Professor Robert Storey from the University of Sheffield previously said.
“However, there is accumulating evidence that [the coronavirus] is associated with a higher risk of heart muscle damage than most common viruses.
“This may partly relate to entry of the virus into the heart muscle cells and partly to the overwhelming inflammation that some patients experience, which can injure the heart muscle.
“Inevitably patients with heart muscle damage are likely to have worse infection and inflammation so it is not surprising those with such damage are more likely to die.
“Similarly, patients with pre-existing heart or lung disease may have less reserve to deal with the consequences of the infection and are at higher risk.”
The Michigan scientists added: “Respiratory failure [when the lungs cannot get enough oxygen into the blood] and prothrombotic events [which promote clotting] that have been extensively described in patients with COVID-19 are probably major contributors to in-hospital cardiac arrest in this setting.”
Early in the outbreak, scientists from the University of Brescia in Italy analysed a woman who showed signs of heart failure a week after the onset of coronavirus symptoms.
The otherwise healthy 53-year-old went to A&E after enduring severe fatigue for two days, later testing positive for the infection.
Although she stabilised following treatment, tests revealed parts of the walls of her heart were abnormally thick, resulting in contractility being reduced by up to 35%.
In July, scientists from the Cleveland Clinic reported a significant increase in the number of people experiencing stress cardiomyopathy, or “broken heart syndrome”.
This can occur if emotional distress triggers dysfunction of the heart muscle.
The circulating coronavirus is one of seven strains of a class of viruses that are known to infect humans.
Of all the strains, the circulating virus is said to be most genetically similar to severe acute respiratory syndrome (Sars), which killed 774 people during its 2002/3 outbreak.
Heart attacks were reported after patients overcame Sars, however, “most of the data” was “anecdotal”.
One study of 75 Sars patients found two in five died as a result of a heart attack, however, these findings were not replicated elsewhere.
Watch: UK coronavirus cases high but deaths low - why?