Almost half of patients who have been hospitalised with severe Covid-19 and who show raised levels of a protein called troponin have damage to their hearts, according to a new study.

Damage 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, published in the European Heart Journal, investigated Covid-19 patients discharged up until June 2020 from six hospitals across three NHS London trusts: Royal Free London NHS Foundation Trust, Imperial College Healthcare NHS Trust and University College London Hospital NHS Foundation Trust.

Patients who had abnormal troponin levels were offered an MRI scan of the heart after discharge and were compared with those from a control group of patients who had not had Covid-19, as well as from 40 healthy volunteers.

Heart could be directly affected in severe Covid-19 patients

Professor Marianna Fontana, professor of cardiology at University College London (UK), who led the research together with Dr Graham Cole, a consultant cardiologist at Imperial 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.”

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% of the 148 patients but scarring or injury to the heart muscle was present in 80 patients (54%). The pattern of tissue scarring or injury originated from inflammation in 39 patients (26%), ischaemic heart disease, which includes infarction or ischaemia, in 32 patients (22%), or both in nine patients (6%). Twelve patients (8%) appeared to have ongoing heart inflammation.

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

“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. 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 findings of the study are limited by the nature of patient selection and included only those who survived a coronavirus infection that required hospital admission.