Covid-19 attacks not only the lungs, but also the heart!

Because the Sars-CoV-2 coronavirus has only recently jumped to humans, virologists and physicians are only learning more about its behaviour and the medical consequences of the infection as the current pandemic progresses. However, it now seems clear that older people and people with pre-existing conditions such as diabetes, high blood pressure, cardiovascular disease, certain cancers or disorders of cerebral circulation have a higher risk of severe courses and also die more often from Covid-19. Most of these patients develop severe pneumonia, which eventually leads to respiratory distress and death.

Indications of acute myocardial damage

But there is now also evidence that covid disease can cause acute damage to the heart muscle. Several studies have shown that patients with severe courses of coronavirus infection often had elevated levels of a biomarker in their blood that is released by destroyed and dying heart muscle cells.

Doctors see this as an indication that the viral infection also attacks the heart - but it is still unknown how. Theoretically, the virus itself could contribute to this damage, but it is also possible and quite likely that the inflammatory processes and immune reactions triggered by the infection are responsible for this damage.

Cases of acute heart damage are also known from viruses closely related to the current Sars-CoV-2 coronavirus, such as Sars-CoV and Mers-CoV. During the Sars epidemic in 2003, a study of 75 Sars patients found that two out of five who died from the disease had an acute heart attack. Cardiac arrhythmias also occurred, as Mohammad Madjid of the University of Texas, author of a review study on this topic in the journal "JAMA Cardiology", reports.

In a study from Italy, researchers led by Riccardo Inciardi from the University of Brescia report the case of a healthy 53-year-old woman who had contracted Sars-CoV-2 and initially developed the classic symptoms of dry cough and fever. About a week after the onset of symptoms, she developed severe fatigue with circulatory problems that were so pronounced that she went to hospital. There she tested positive for Covid and was referred to cardiology.

Investigations there revealed that the patient showed clear signs of acute myocarditis - an inflammation of the heart muscle. "This case underlines that the heart can be affected as a complication of Covid-19 - and that even without clear symptoms and without pneumonia," Inciardi and his colleagues report. Madjid has a similar view: "It is likely that the heart muscle is affected by the coronavirus and the disease it causes, even in the absence of previous heart disease."

A wake-up call

This seems to indicate that covid disease not only causes respiratory symptoms and the inflammatory reactions associated with infection, but can also attack the heart. Recent studies from China show that in this case, the risk of death for patients increases significantly.

A team led by Shaobo Shi from Wuhan University, for example, reported on the basis of 416 patients that there was evidence of myocardial damage in almost 20 percent of these patients. Those affected had a significantly higher risk of dying from covid-19 - half of them, while only 4.5 per cent of the patients without elevated troponin levels and other evidence of myocardial damage died. Another study with 187 patients showed a similar result: it determined a mortality of 59.6 percent in people with indicators of heart muscle damage, of those with normal troponin levels in the blood, 8.9 percent died.

"Remarkably, although the highest mortality rates were observed in patients who had high troponin levels and prior cardiovascular disease," writes Robert Bonow of Northwestern University in an accompanying editorial in JAMA Cardiology. "But mortality rates were also substantial in those who had elevated troponin levels without such pre-existing conditions." To be sure, it is not yet clear what the specific mechanisms and relationships behind this effect are. "But the wake-up call has been sounded," says Bonow.

Sources:

• Mohammad Madjid et al, JAMA Cardiology, doi: 10.1001/jamacardio.2020.1286
• Riccardo Inciardi et al, doi: 10.1001/jamacardio.2020.1096
• Shaobo Shi et al., doi:10.1001/jamacardio.2020.0950
• Bonow et al, JAMA Cardiology, doi: 10.1001/jamacardio.2020.1105