Although COVID-19 is primarily a respiratory illness, the effects of the viral infection cascade into other organs, including the gastrointestinal tract, kidneys, liver, and heart.

A new study focused specifically on how COVID-19 can affect the heart, finding that cardiovascular-related complications are worrisome in a large percentage of patients.

Cardiologists from across the world, from China to Italy to New York, have documented how many COVID-19 patients go on to develop heart problems, with many succumbing to cardiac arrest. As many as one in five COVID-19 patients develop cardiac damage, which can lead to heart failure and death.

But why is a respiratory virus having such a strong effect on the heart?

About half of all hospitalized coronavirus patients have at least one underlying chronic disease, the most common being cardiovascular disease. So far, data suggests that those with heart disease are potentially ten times more likely to die of the infection that patients without heart problems.

It’s rather unclear whether these heart problems are caused by the virus itself or a byproduct of the body’s immune reaction. Now, the new study authored by Chinese researchers attempts to dispel some of these confusions by how the coronavirus attacks the heart.

A complicated virus

After conducting a systematic review of COVID-19 hospitalized cases in China, the researchers found that the infection can damage heart tissue in three primary ways: directly infecting heart muscle, enhancing stress on already weakened cardiovascular systems, and inflammation.

Damage to the heart can trigger certain well known COVID-19 symptoms in critical cases, such as respiratory failure and hypoxemia (insufficient oxygen in the blood). As a consequence, patients can then experience arrhythmias, heart attacks, and cardiac arrest, the researchers wrote in the journal Frontiers in Cardiovascular Medicine.

The most dangerous outcome seems to be hyper-inflammation that can trigger cytokine storm — an immune system overreaction that can lead to organ failure.

“Inflammation plays an important role in the development and complications of cardiovascular diseases and we have seen that COVID-19 patients with greater signs of an inflammatory response are more likely to suffer serious cardiovascular events and are at greater risk of dying,” Professor Shuyang Zhang, lead author of this research from the Department of Cardiology at the Peking Union Medical College Hospital Beijing, China, said in a statement.

Zhang and colleagues also studied various cardiovascular anti-inflammatory therapies that are currently under clinical trials. But although there are some positive signs that drugs like hydroxychloroquine and azithromycin can improve cardiovascular outcomes, they can also go the other way, increasing the risk of cardiovascular impairment.

Therefore, the authors advise caution and warn against the use of pre-clinical drugs in a hospital setting for treating COVID-19 patients. More research is thus desperately needed to figure out what treatments have real potential.

“Considering that these drugs may be essential in the clinical management of COVID-19 patients, especially the anti-viral agents, cardiovascular protective strategies are urgently needed to improve the overall prognosis.”

“We hope our study provides useful information to the global community hoping to improve the clinical management of COVID-19 during this pandemic.”

In the meantime, patients with a known history of cardiovascular disease should exert extra caution. Impeccable hygiene and social distancing are paramount in this case.