Around 50 per cent of patients who have been hospitalised with severe Covid-19 display heart damage months after having had the disease, a UK study has found.
Those with raised levels of a protein called troponin have damage to their hearts that can be linked to Covid-19. The injury was detected by magnetic resonance imaging (MRI) scans at least a month after discharge.
The findings, published in the European Heart Journal, are another indication of “long Covid” effects lingering after the acute phase of the disease but are likely to lead to better treatments of all its forms.
Damage found includes inflammation of the heart muscle (myocarditis); scarring or death of heart tissue (infarction), restricted blood supply to the heart (ischaemia) and combinations of all three.
The study of 148 patients from six acute hospitals in London is the largest to date on convalescing Covid-19 patients who had raised troponin levels indicating possible heart problems.
Troponin is released into the blood when the heart muscle is injured. Raised levels can occur when an artery becomes blocked or there is inflammation of the heart. Many hospitalised patients with Covid-19 have raised troponin levels during the critical illness phase, when the body mounts an exaggerated immune response to the infection.
Research leader Marianna Fontana, professor of cardiology at University College London, 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,” Prof Fontana said.
“The recovering Covid-19 patients had been very ill; all required hospitalisation, and all had troponin elevation, with around one in three having been on a ventilator in the intensive care unit,” Prof Fontana said.
“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.”
In the most severe cases, there are concerns this injury may increase the risks of heart failure in the future, but more work is needed to investigate this further.
Injury relating to inflammation and scarring of the heart is common in Covid-19 patients with troponin elevation discharged from hospital, though it is of limited extent, Prof Fontana said.
“These findings give us two opportunities: firstly, to find ways of preventing the injury in the first place, and from some of the patterns we have seen, blood clotting may be playing a role, for which we have potential treatments,” she explained.
Secondly, detecting the consequences of injury during convalescence may identify subjects who would benefit from specific supporting drug treatments to protect heart function over time.
The study only included those who survived a coronavirus infection that required hospital admission. A German study found ongoing heart problems in up to 78 per cent of Covid-19 patients who were less sick and mostly did not require admission to hospital.