As we continue to learn more about COVID-CoV-2, it is not yet clear all the ways the disease may affect our bodies in the short- and long-term. While most persons recover and return to normal health after a COVID-19 infection, some individuals have symptoms that can last long after recovery and, although considered rare, very long-term, severe complications have been reported as well. Specifically, inflammation of the heart muscle, which can lead to an increased risk for heart rhythm disturbances and heart failure — a rare, but serious consequence of a COVID-19 infection.

According to Lori Daniels, MD, cardiologist at UC San Diego Health, COVID-19 seems to serve as a “stress test” for the body, which could explain why individuals with underlying heart conditions are more at risk for severe COVID-19 infections.

Daniels explains:

What effects does COVID-19 have on the heart?

COVID-19 can have effects on many organ systems in the body, including the heart and cardiovascular system. In the short term, it can have a variety of effects on the heart. One manifestation is a weakening of the heart muscle due to either a direct effect of the virus, the body’s own inflammatory response or the stress of critical illness; this can lead to heart failure and even shock. In addition, COVID-19 can result in myocardial infarctions — also known as heart attacks — either by precipitating plaque rupture in the heart arteries or by creating excessive demands on the heart. We are also seeing an increase in heart rhythm disturbances due to COVID-19. Additionally, COVID-19 can cause inflammation of the pericardium, which is the sac that surrounds the heart; this can lead to fluid accumulation around the heart. Finally, COVID-19 can predispose the body to blood clots; these can form in the heart arteries, the brain or other blood vessels.

In the long term, there is evidence that COVID-19 can lead to ongoing inflammation of the heart muscle, or myocarditis, and potentially to fibrosis or scarring of the heart. How common this is, and why this persists in some people, is somewhat controversial and is being actively studied. Some patients after recovery from COVID-19 have also reported ongoing sensations of their heart pounding, or palpitations.

In addition to these problems, we and others are also seeing heart problems that are not due directly to the virus itself, but are due to people delaying treatment for other heart problems, such as heart attacks and heart failure, out of fear of coming to the hospital during the pandemic. This is extremely unfortunate, since treatment at the hospital is safe, but delaying care for these medical emergencies can be deadly.

How does COVID-19 affect the circulatory system in general?

The virus is able to directly affect the lining of blood vessels, also known as the endothelium. This may be one of the reasons that patients with COVID-19 are prone to blood clots in the legs, lungs and brain.

Has this ever happened with other viruses, such as influenza?

Influenza can also have extensive effects on inflammation and on the clotting system, and can be a trigger for cardiovascular events. However, in general these effects from COVID-19 are far more potent. Clotting disorders can also happen with influenza, but again seem to be more common and more severe in COVID-19. Though influenza and other viruses also can have disproportionate effects on individuals with underlying cardiovascular disease, COVID-19 has a still higher mortality and case-fatality rate, as well as an increased risk of adverse outcomes in this high-risk population.

Why are strokes linked to COVID-19?

COVID-19 seems to cause a hypercoagulable state in the body, which is an increased risk of forming blood clots. There are a variety of manifestations of this COVID-19-induced condition, ranging from asymptomatic to blood clots in the deep veins of the legs, in the lungs, or in arteries of the extremities, to widespread severe clotting. Microscopic clots have also been found when lungs are examined at autopsy. When blood clots form in the arteries of the brain, it leads to a stroke.

The reason for the pro-clotting state in COVID-19 is unclear, but may be related to endothelial cell injury from the virus, prolonged immobilization among patients suffering from COVID-19 infection leading to blood stasis, and virus-induced changes in circulating blood factors, such as clotting factors and activation of platelets.

Why are individuals with underlying heart conditions more at risk for severe COVID-19 infections?

There are a few reasons why underlying heart conditions place individuals at greater risk for COVID-19 infections. When an individual has a weaker heart muscle or blockages in their heart arteries to begin with, it can weaken their ability to fight off and survive a severe illness. In the setting of a severe infection such as COVID-19, there is less oxygen getting into the blood, as well as fevers, inflammation, blood clotting problems and unstable blood pressures, all of which puts significant hemodynamic demands on the heart. Individuals with weaker hearts may not be able to withstand these stressors.

In addition, conditions like diabetes and obesity, which are associated with both heart disease as well as severe COVID infection, are considered inflammatory conditions themselves that may weaken the immune response, worsen the inflammatory reaction, and/or increase the endothelial cell vulnerability, thereby potentiating the infection. Other biologic reasons have been proposed as well, including upregulation by medications and underlying medical conditions of the ACE2 receptors, which SARS-CoV-2 uses to enter cells; however, this is an area of ongoing investigation.

What can we do to protect ourselves?

People with underlying medical conditions can help protect themselves and/or prevent severe cases of COVID-19 by following a healthy lifestyle, properly managing medical conditions such as diabetes and high blood pressure among others, following a healthy diet, maintaining regular exercise, and having good adherence to prescribed medications.

For patients with heart disease specifically, including high blood pressure, our research has shown that among patients hospitalized for COVID-19, those who were taking their blood pressure medications, especially statin medications, prior to hospital admission had a significantly lower risk of dying from COVID-19 or developing a severe COVID-19 infection.

And, as always, prevention is the best medicine. Continue to wear masks in public when you are around others, avoid being indoors unmasked with individuals outside your immediate household, wash your hands frequently, and get vaccinated as soon as you are able.