Troponin elevation is common in hospitalized COVID-19 patients, but underlying aetiologies are ill-defined.
Researchers have used multi-parametric cardiovascular magnetic resonance ( CMR ) to assess myocardial injury in recovered COVID-19 patients.
One hundred and forty-eight patients ( 64 ± 12 years, 70% male ) with severe COVID-19 infection [ all requiring hospital admission, 48 ( 32% ) requiring ventilatory support ] and troponin elevation discharged from six hospitals underwent convalescent CMR ( including adenosine stress perfusion if indicated ) at median 68 days.
Left ventricular ( LV ) function was normal in 89% ( ejection fraction 67% ± 11% ).
Late Gadolinium enhancement and/or ischaemia was found in 54% ( 80/148 ). This comprised myocarditis-like scar in 26% ( 39/148 ), infarction and/or ischaemia in 22% ( 32/148 ) and dual pathology in 6% ( 9/148 ).
Myocarditis-like injury was limited to three or less myocardial segments in 88% ( 35/40 ) of cases with no associated LV dysfunction; of these, 30% had active myocarditis.
Myocardial infarction was found in 19% ( 28/148 ) and inducible ischaemia in 26% ( 20/76 ) of those undergoing stress perfusion ( including 7 with both infarction and ischaemia ).
Of patients with ischaemic injury pattern, 66% ( 27/41 ) had no past history of coronary disease.
There was no evidence of diffuse fibrosis or oedema in the remote myocardium ( T1: COVID-19 patients 1033 ± 41 ms versus matched controls 1028 ± 35 ms; T2: COVID-19 46 ± 3 ms vs. matched controls 47 ± 3 ms ).
In conclusion, during convalescence after severe COVID-19 infection with troponin elevation, myocarditis-like injury can be encountered, with limited extent and minimal functional consequence.
In a proportion of patients, there is evidence of possible ongoing localized inflammation.
A quarter of patients had ischaemic heart disease, of which two-thirds had no previous history.
Whether these observed findings represent pre-existing clinically silent disease or de novo COVID-19-related changes remain undetermined.
Diffuse oedema or fibrosis was not detected. ( Xagena )
Kotecha T et al, Eur Heart J 2021;doi:10.1093/eurheartj/ehab075