What we know (and don’t know) about COVID-19 and heart damage

With COVID-19 surging once again, I’m getting a lot of questions about how the novel coronavirus (SARS CoV-2) can affect the heart. While the most common and prominent symptoms are mild respiratory symptoms and pneumonia, a number of heart complications including myocarditis (inflammation of the heart), arrhythmias, and blood clots occur not uncommonly. Let’s review.

Heart damage due to COVID-19

COVID-19 can result in acute cardiac injury, or damage to the heart muscle. This ranges dramatically from mild damage without symptoms to full blown heart failure that can require an intensive care unit stay or death.

Cardiac injury can be detected by a blood test, called troponin, showing that the heart muscle has been damaged, as well as evidence on different heart tests such as an EKG, echocardiogram (an ultrasound of the heart), or MRI. It is not uncommon, with rates ranging from 7% to 28% of all hospitalized patients (variable as different studies used different definitions).

Those who do have evidence of heart damage have higher rates of requiring ICU-level care as well as death than those that do not. It causes about 40% of all deaths due to COVID-19.

Heart injury due to COVID-19 is more common in people with pre-existing heart disease, as well as those who are older or have high blood pressure or diabetes. Evidence of heart damage occurs on average 15 days after symptoms first begin, but can occur even in those who did not have any respiratory symptoms at all.

The heart damage that occurs from COVID-19 is thought to be due to a variety of mechanisms including

• direct viral injury and inflammation (myocarditis)

• dysfunction of the small blood vessels

• stress on the heart

• blood clots

• rupture of blockages in arteries of the heart (heart attack)

What is myocarditis and pericarditis?

Myocarditis is inflammation of the heart muscle. This can affect its ability to pump blood to the body. It is commonly due to infections, but there are noninfectious causes as well. It is most commonly due to viruses like influenza, enterovirus, and parvovirus, but can also be caused by bacteria or other infections like Lyme disease. Noninfectious causes include autoimmune conditions such as lupus as well as toxins. Many times, no cause is identified. It can result in very little symptoms to mild dysfunction of the heart muscle to severe heart failure.

Myocarditis due to COVID-19 may result from direct infection of the virus or from the body’s immune response, or both. Several studies over the last few months have made us concerned that myocarditis may be more common than initially thought, and may occur even in those who weren’t sick enough to require hospitalization. Evidence of inflammation by imaging and bloodwork can be found months out from the initial infection. Unlike other types of cardiac injury due to COVID-19, myocarditis affects the young and healthy. The true rate of myocarditis due to COVID-19 is still unclear, and we are awaiting longterm followup. Prior to the pandemic, it was an important cause of sudden cardiac death in young athletes, and may be even more so currently.

Pericarditis is inflammation of the sac around the heart, also commonly caused by infections. A recent study found that about a third of the young, asymptomatic athletes they looked at had evidence of either pericarditis or mild fluid around the heart (pericardial effusion).

What are other heart complications that can occur?

Other heart complications include arrhythmias, or heart rhythm issues, including dangerous rhythms that can result in cardiac arrest. Heart failure, when the heart muscle is weak and cannot pump blood properly, and cardiogenic shock, when the body’s vital organs do not receive sufficient blood, can also occur. Blood clots, in both the veins and the arteries, has also been reported.

Even after recovery from the initial infection, long-term complications are possible. Although it is too early to know, we worry that while many will recover, some may end up with permanent damage to the heart, such as heart failure. Others may develop scarring in the heart that can produce dangerous heart rhythm issues.

Possible sign and symptoms to be concerned about

While the majority of people will recover from COVID-19, particularly those that are young and without other medical problems, it’s important to keep an eye on your symptoms and recovery. Many will experience some prolonged fatigue, but pronounced shortness of breath with walking or lying down, chest pain, heart palpitations, lightheadedness, or swelling in the legs could be a sign of heart complications and a reason to call your doctor. Given that issues have been reported months out after recovery, keep this in mind as you recover.

What is the treatment for COVID related cardiac injury

The treatment differs greatly depending on the type of cardiac injury and severity. For myocarditis, if the heart pump function is low, typically standard medications for heart failure are used. Refraining from exercise for 3-6 months is also recommended due to the possible risk of dangerous heart rhythms from the residual heart inflammation. Other treatments are directed at the cause including blood thinners for blood clots and standard heart medicines for heart attacks. Doctors usually monitor the heart’s recovery with imaging, such as echocardiograms or MRIs, and other heart tests checking for rhythm issues (like a Holter or event monitor) and exercise tolerance (stress test).

Key take homes

There is still a lot of uncertainly regarding the frequency and long-term outcomes of COVID-19 related cardiac injury. Cardiac injury, particularly in hospitalized patients, portends a poor prognosis and is clearly responsible for a significant portion of the COVID-19 related deaths. It remains to be seen how common COVID-19 related myocarditis truly is (particularly in young, healthy individuals), and the long-term implications. As with everything related to this virus, we will continue to learn more as we slog through this pandemic. Continuing to remain vigilant with wearing a mask, social distancing, and (finally!) getting a vaccine when it becomes available to the general population remain our best prevention measures.