Around 50 per cent of Covid-19 hospitalised patients have elevated levels of a protein called troponin that causes damage to their hearts, as per a new study.

For the study, published in the European Heart Journal, the researchers carried out MRI scans to detect the injury at least a month after discharge.

The findings observed inflammation of the heart muscle (myocarditis), scarring or death of heart tissue (infarction), restricted blood supply to the heart (ischemia), and combinations of all three in some cases.

The study of 148 patients from six acute hospitals in London is the largest study conducted to understand patients with increased troponin levels, which indicates a possible problem with the heart.

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Troponin is released into the blood when the heart muscle is injured. Elevated levels can occur when an artery becomes blocked or due to inflammation of the heart. Many patients who are hospitalized with Covid-19 have raised troponin levels during the critical illness phase when the body mounts an exaggerated immune response to the infection.

Troponin levels were elevated in all the patients in this study who were then followed up with MRI scans of the heart after discharge in order to understand the causes and extent of the damage.

Lead researcher Professor Marianna Fontana, professor of cardiology at University College London (UK), said: “Raised troponin levels are associated with worse outcomes in Covid-19 patients. Patients with severe Covid-19 disease often have pre-existing heart-related health problems including diabetes, raised blood pressure, and obesity.”

“During severe Covid-19 infection, however, the heart may also be directly affected. Unpicking how the heart can become damaged is difficult, but MRI scans of the heart can identify different patterns of injury, which may enable us to make more accurate diagnoses and to target treatments more effectively,” added Fontana.

“We found evidence of high rates of heart muscle injury that could be seen on the scans a month or two after discharge. Whilst some of this may have been pre-existing, MRI scanning shows that some were new, and likely caused by Covid-19. Importantly, the pattern of damage to the heart was variable, suggesting that the heart is at risk of different types of injury,” Fontana further added.

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The function of the heart’s left ventricle, the chamber that is responsible for pumping oxygenated blood to all parts of the body, was normal in 89 per cent of the 148 patients. However, scarring or injury to the heart muscle was present in 80 patients (54 per cent).

The pattern of tissue scarring, or injury originated from inflammation in 39 patients (26 per cent), ischemic heart disease, which includes infarction or ischemia, in 32 patients (22 per cent), or both in nine patients (6 per cent). Twelve patients (8 per cent) appeared to have ongoing heart inflammation.

Prof. Fontana said: “Injury relating to inflammation and scarring of the heart is common in Covid-19 patients with troponin elevation discharged from a hospital but is of limited extent and has little consequence for the heart’s function.”

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