Background Patients after post-COVID suffer from persistent cardiac symptoms. Aim of this study was to analyze long-term cardiac involvement in patients suffering at least three months from post-COVID symptoms.

Methods We prospectively examined the clinical and imaging data of 94 patients at a median of 99 days (IQR 64-110 days) after COVID-19 infection from January 2021 to March 2022. Left ventricular performance was evaluated by cardiovascular magnetic resonance imaging in all patients after COVID-19 infection compared to a healthy control group (n=100). A follow-up scan was conducted in case of a positive CMR meeting the criteria for myocarditis after a median of 87 days (IQR 82-105) after initial CMR. Major adverse clinical events and cardiovascular death were determined for each patient at a median of 269 days (IQR 146-205days) after initial assessment.

Results A total of 194 patients were included into the study. The majority of post-COVID patients had a mild clinical course after initial infection. There was no significant difference between post-COVID patients and the group of healthy controls regarding systolic leftventricular ejection fraction (63.6% vs. 63.2%, p=0.85). Classical CMR criteria for myocarditis were slightly elevated in the post-COVID patients. We observed a significant difference in myocardial strain parameters between both groups: peak radial strain (GRS) -2.9% (-5.4; -0.4), p=0.025, peak circumferential strain (GCS) 1.2% (0.4; 2.0), p=0.003, systolic circumferential strain rate 0.08/s (0.01; 0.15), p=0.02; systolic longitudinal strain rate 0.08/s (0.01; 0.15), p=0.035. Strain-pattern in post-COVID patients with confirmed myocarditis remained altered in a follow-up scan after 87 days; IQR (82-105), while myocardial oedema and Late Gadolinium Enhancement (3.8±2.6% vs.0%, p=0.016) resolved completely.

Conclusions Patients with ongoing post COVID symptoms show long-term myocardial mechanical changes in CMR, while traditional leftventricular functional parameters are normal. Systolic strain pattern is altered in these patients and might be one explanation for prolonging symptoms after COVID-19 infection in patients with long-term symptoms. These findings underline the need for further investigation after prolonging post-COVID symptoms to detect long-term myocardial changes.