SARS-CoV-2, the virus that causes COVID-19, affects various organs and systems in the body, including the cardiovascular system. What do we currently know about its impact on the heart? This feature looks at the latest research and reveals what cardiologists have observed in the hospital setting.

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All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

SARS-CoV-2 has exhibited the ability to impact more than the respiratory system. Since its emergence, people who have had COVID-19 also report symptoms affecting the brain, gastrointestinal system, and heart.

Observational and research data suggest that COVID-19 impacts the heart in hospitalized patients, those with mild cases of the disease, and people with no prior heart-related conditions. These heart-related issues may remain long after the illness has passed, regardless of whether the individual experienced a severe or mild case of COVID-19.

Doctors still do not fully understand how SARS-CoV-2 causes heart problems, the extent of these issues, or whether this aspect of the virus should cause extreme concern.

In this feature, we sift through the latest research to understand the impact COVID-19 has on the heart. We also spoke with one cardiologist from a hospital intensive care unit that has experienced a heavy influx of patients with COVID-19.

Although many viruses, such as influenza, can cause heart-related issues, SARS-CoV-2 seems to impact the cardiovascular system more frequently.

According to an article published in Science, of the family of seven human coronaviruses, scientists know that most affect the lungs but not the heart. SARS-CoV-2 is different because it may have a propensity to cause cardiac-related issues, such as inflammation of the heart, heart attack-like symptoms, and heart rhythm irregularities.

However, other, rather alarming data indicates that approximately 25% of people hospitalized with COVID-19 have cardiovascular complications, contributing to about 40% of all COVID-19-related deaths.

Interestingly, people with severe cases of the disease might not be the only individuals at risk for heart complications. Additional research published in JAMA Cardiology suggests that people who have had COVID-19 may experience cardiac involvement even with mild illness.

In the study, researchers used cardiac magnetic resonance imaging to examine the hearts of 100 German people who had recovered from COVID-19. Of these participants, 78 had cardiac involvement, and 60 showed ongoing heart muscle tissue inflammation. These findings were independent of the length of time after the original diagnosis, pre-existing conditions, and the severity and overall course of COVID-19.

Even young adults may be at risk of COVID-19-related heart complications.

Recent research, also published in JAMA Cardiology, found that out of 26 college-aged competitive athletes who previously tested positive for COVID-19, four (15%) had cardiovascular magnetic resonance (CMR) findings that suggested myocarditis.

Eight additional athletes (30.8%) exhibited late gadolinium enhancement (LGE) without T2 elevation, which suggests prior heart muscle injury.

Both LGE and T2 are techniques doctors use to characterize the myocardium (cardiac muscle) and determine any damaged areas.

Because of a limited number of study participants, the relationship between COVID-19 and myocardial injury in athletes needs more extensive studies, including control populations.

To understand the scope of COVID-19-related heart complications observed in the clinical setting, Medical News Today spoke with Joshua I. Goldhaber MD, Cardiologist and Associate Director of the Coronary Intensive Care Unit, Smidt Heart Institute at Cedars Sinai, in Los Angeles, California.

Cedars-Sinai Medical Center in Los Angeles is one of several hundred hospitals in the US that have reported full intensive care units due to COVID-19 as of January 28.

Dr. Goldhaber told MNT that at the Smidt Heart Institute at Cedars-Sinai, most of the patients who experience COVID-19-related heart complications are people who already have an underlying cardiac condition, such as heart failure or coronary disease.

In patients with COVID-19 and underlying cardiac conditions, the illness tended to exacerbate their heart issues, which increases the likelihood that these patients would need intubation in the intensive care unit (ICU).

Early in the pandemic, Dr. Goldhaber and his colleagues were concerned there was going to be an increased rate of cardiac findings related to COVID-19.

Dr. Goldhaber said, “we were surprised — and we continue to be surprised — that we have not seen that to the extent that we believed [we would], based on data that had been coming out of China early on in the pandemic.”

Dr. Goldhaber also noted that his team has not seen many new cardiac problems they could directly relate to COVID-19 disease.

Dr. Goldhaber said:

“During influenza season, we always see an increase in admissions of patients with heart failure exacerbations. So, it’s not surprising that a viral illness might cause inflammation, myocarditis, and pericarditis. But frankly, I’ve seen less than usual, which really does fly in the face of what we were all expecting here.”

Scientists are just beginning to gather evidence of how SARS-CoV-2 affects the heart. There are two main theories, each involving different aspects of the virus and its impact on the cardiovascular system.

Firstly, inflammation caused by the body’s robust immune response during COVID-19 may play a role in provoking heart complications. This immune response can indirectly damage heart tissues by diminishing the heart’s blood supply and increasing the risk of heart inflammation.

Researchers also suspect that SARS-CoV-2 may cause heart tissue damage because of its distinct spike protein that can directly attach to and enter cardiac cells by binding with the heart’s angiotensin-converting enzyme 2 (ACE2) receptors.

Whether immune system-related or a result of SARS-CoV-2 directly attaching to receptors in the heart, research has revealed evidence of heart cell damage in people who have had COVID-19.

Scientists examining the hearts of people who died of COVID-19 early in the pandemic found evidence of blood clotting issues (microvascular thrombosis) and heart cell death (necrosis). Areas of muscle cell death occurred in 35% of the 40 hearts examined. The scientists also found blood clots in the capillaries, or small blood vessels, in the heart tissue.

Because of the lack of large-scale studies, it is necessary to carry out further investigation to fully uncover the mechanisms behind the impact of SARS-CoV-2 on the heart.

Standard treatment for people hospitalized for COVID-19 generally includes remdesivir and dexamethasone. For the most part, this does not change for people with pre-existing heart conditions.

At Cedars-Sinai, individuals admitted to the hospital with pre-diagnosed heart problems receive typical cardiac therapies in addition to medications for COVID-19.

According to Dr. Goldhaber, treatment plans at the Cedars-Sinai medical intensive care unit (ICU) also incorporate anticoagulants: “We have a very low threshold [to use anticoagulants in] patients who are diagnosed with COVID-19 to prevent all COVID-related thrombosis. Those patients who got prophylactic anticoagulation were patients who didn’t have any cardiac symptoms at all.”

No matter the treatment regimen used, Dr. Goldhaber and his colleagues have found that, in general, patients with pre-existing cardiac conditions had to stay longer in the ICU than individuals without underlying heart problems.

COVID-19 is showing a propensity to cause lasting effects. According to the BMJ, approximately 10% of people who have had the disease experience prolonged illness or respiratory, cardiac, and neurological symptoms.

As far as long-term heart problems, Dr. Goldhaber said, “it’s too early to tell, but [that is] definitely something we’re worried about, given that there are patients who haven’t had pre-existing cardiac issues, who are complaining of exercise intolerance, and other symptoms that could be cardiac related.”

“There’s concern about these ‘long haulers’ that are going to have cardiac-related problems that pop up, maybe weeks, months after their acute illness. There are probably other kinds of secondary effects that we don’t see acutely in the hospital that manifest themselves later, which is one of the reasons, and one of the great arguments for people getting a vaccine rather than taking the risk of getting COVID-19.”

-Dr. Joshua I. Goldhaber

Aside from COVID-19-related cardiac complications, Dr. Goldhaber told MNT that routine or emergency heart care has also been challenging throughout the pandemic.

“Here in Los Angeles, where community transmission has been so high in the last couple of months, [when] any patient comes into the emergency room with a cardiac symptom — whether they have obvious [COVID-19 symptoms] or not — we just assume they have COVID-19,” Dr. Goldhaber explained.

This means healthcare providers must take precautions with personal protective equipment (PPE), isolating catheterization labs, and special cleaning processes. These extra precautions are time-consuming in an emergency.

Because of the urgency to move patients who present with symptoms of a heart attack to the catheterization lab, healthcare staff only have time to do a rapid COVID-19 test, which, Dr. Goldhaber claims, “is not that accurate.”

There are many reports that the COVID-19 pandemic has put an incredible strain on hospitals and medical facilities worldwide.

Dr. Goldhaber claims the situation at Cedars-Sinai has been no different:

“I’m the director of the Cardiology Fellowship Program, the training program for new cardiologists. And like many of the healthcare workers, the cardiology fellows who happen to be trained in intensive care medicine have been called upon to do double duty, not only as cardiologists but also to work in the COVID-19 units to supplement the critical care doctors there who are overwhelmed.”

Dr. Goldhaber said around two-thirds of Cedar-Sinai cardiology fellows have assisted patients in the COVID-19 ICU.

However, even in the hardest-hit areas, positive news is beginning to emerge that hopefully indicates a downturn in new cases of COVID-19. Dr. Goldhaber added: “Things are finally lightening up a little bit. It seems to be improving [as] the number of COVID-19 positive patients in the ICU today is half of what it was a month ago.”

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