When Covid-19 first emerged, doctors were stunned by the virus' ability to ravage the respiratory system. Today, they understand the disease's reach goes far beyond the lungs, extending to the GI tract, kidneys, and liver.

A new report illuminates another part of the body that the virus attacks: the heart.

According to doctors on the frontlines, as many as one in five Covid-19 patients experience arrhythmias, heart attacks, and cardiac arrest triggered by the illness. People with underlying conditions, like chronic heart disease, are at a higher risk for complications or mortality from Covid-19.

John Hwa, a cardiology researcher and clinician at the Yale School of Medicine, says that based on heart biomarkers, as high as 20 to 30 percent of hospitalized Covid-19 patients may have some heart damage. (Hwa was not a part of this new study.)

“The Covid-19 infection can tip the already compromised heart toward rapid deterioration,” Hwa tells Inverse.

In the new study, cardiologists working in China, armed with the knowledge gained from treating Covid-19 patients, offer a way forward: They explain how the disease attacks the heart, which may prove useful as doctors work to serve their patients.

Their report was published Thursday in the journal Frontiers in Cardiovascular Medicine.

Almost half of hospitalized Covid-19 patients have a chronic medical illness. The majority are affected by cardiovascular disease. Pandemic or not, heart disease is the leading cause of death in the United States.

“We know that patients with heart disease have worse outcomes if they develop Covid-19," Kiran Musunuru, a cardiologist at the University of Pennsylvania, tells Inverse. Musunuru was not involved in the new study.

"They are possibly ten times more likely to die of the infection than patients without heart disease."

After observing these dire outcomes play out in the hospital, a group of Chinese cardiologists conducted a systematic review of the potential causes and therapies that might buffer Covid-19's effect on the heart.

They also explored how potential Covid-19 treatments like hydroxychloroquine and azithromycin influence heart health.

They found that Covid-19 can attack the heart in three dangerous ways: by directly infecting the heart muscle, putting undue stress on already weakened hearts, or causing widespread inflammation.

In turn, that inflammation can induce a cytokine storm, an immune system overreaction that can harm heart cells.

Hwa adds that heart damage can result from other Covid-19 symptoms like respiratory failure and hypoxemia (a lack of oxygen). If severe, these can all potentially lead to heart failure, abnormal heart rhythms, and death, Hwa explains.

Hyper-activated inflammation plays a pivotal role in these bad outcomes, the report suggests.

"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," lead author Shuyang Zhang, a cardiologist at Peking Union Medical College Hospital in Beijing, China, explains.

If doctors can reduce the inflammatory response patients have to Covid-19, they may be able to help prevent heart damage or adverse cardiac events.

Protecting the heart — Zhang and her team argue in the study that proven cardiovascular anti-inflammatory therapies can reduce these inflammation responses. These medications, like colchicine, could specifically be used to treat Covid-19 patients that are at risk of, or have developed, cardiovascular problems.

This guidance, however, isn't universally agreed on. Musunuru and Hwa caution that it's still too early to provide clinical guidance based on the current research.

Physicians should "definitely not" be administering cardiovascular anti-inflammatory medications as standard protocol for Covid-19 patients with a risk of heart problems, outside of clinical trials, Musunuru argues.

"In general, anti-inflammatory medications have actually not been very helpful for patients with heart disease," he explains.

Meanwhile, Hwa notes that "no anti-inflammatory medications have yet been definitively proven to be effective against Covid-19."

More randomized controlled trials, the gold standard of clinical research, would help decipher which, if any, medications make a meaningful difference.

The new report also details how safe potential — and pre-clinical — Covid-19 treatments are when it comes to the heart, including: steroids, hydroxychloroquine, and anti-viral medications. In turn, the team warns against using pre-clinical drugs for treating Covid-19 because of their "unknown efficacy and safety risks."

On this point, all the cardiologists agree: "All these therapies are risky with potentially serious side effects," Hwa says. Hydroxychloroquine and azithromycin, for example, can push the heart into life-threatening abnormal rhythms, especially when the drugs are used in combination, Musunuru adds.

"This is not theoretical — patients in clinical trials with these drugs have died from these abnormal heart rhythms," Musunuru notes. These adverse outcomes prompted the United States FDA to issue a warning last week cautioning the use of these drugs outside hospital settings.

For now, there are no verified medications that can help patients with heart disease fight off, or prevent, becoming ill with Covid-19. This means patients with heart disease should be particularly careful about social distancing, washing their hands frequently, and wearing face coverings when they are out in public.

"Patients with heart disease, and the clinicians taking care of them, should certainly do all the things they did before the pandemic," Musunuru says.

This involves taking the medications known to protect people against adverse cardiovascular events, exercising, and adhering to a healthy diet.

Abstract: In December 2019, Coronavirus Disease 2019 (COVID-19) caused by SARS-CoV-2, occurred in China and has currently led to a global pandemic. In addition to respiratory involvement, COVID-19 was also associated with significant multiple organ dysfunction syndrome (MODS). Cardiovascular impairment has been observed and is now drawing growing attention. Cardiovascular protective strategies are urgent and of great significance to the overall prognosis of COVID-19 patients. Direct viral infection, cytokine storm, and aggravation of existing cardiovascular diseases were recognized as possible mechanisms of cardiovascular impairment in COVID-19. Hyperactivated inflammation plays an important role in all three mechanisms and is considered to be fundamental in the development of cardiovascular impairment and MODS in COVID-19. Therefore, in addition to conventional cardiovascular treatment, anti-inflammatory therapy is a reasonable strategy for severe cases to further enhance cardiovascular protection and potentially mitigate MODS. We reviewed the inflammatory features and current promising treatments of COVID-19 as well as cardiovascular anti-inflammatory therapies that have been verified in previous clinical trials with positive outcomes. We believe that targeting the central pathway (IL‐1β, TNF‐α, IL‐6), balancing the Th1 and Th2 response, and administering long-term anti-inflammatory therapy might be promising prospects to reduce cardiovascular impairment and even MODS during the acute and recovery phases of COVID-19. The cardiovascular anti-inflammatory therapies might be of great application value to the management of COVID-19 patients and we further propose an algorithm for the selection of anti-inflammatory therapy for COVID-19 patients with or at high risk of cardiovascular impairment. We recommend to take the experiences in cardiovascular anti-inflammatory therapy as references in the management of COVID-19 and conduct related clinical trials, while the clinical translation of novel treatments from preclinical studies or in vitro drug screening should proceed with caution due to unguaranteed efficacy and safety profiles