Elevated Extracellular Volume Fraction and Reduced Global Longitudinal Strains in Patients Recovered from COVID-19 without Clinical Cardiac Findings.

Background It is unknown if there are cardiac abnormalities in participants recovered from COVID-19 without cardiac symptoms and those who have normal biomarkers and normal ECGs. Purpose To evaluate cardiac involvement in participants recovered from COVID-19 without clinical evidence of cardiac involvement using cardiac MRI Materials and methods In this prospective observational cohort study, 40 participants recovered from COVID-19 with moderate(n=24) or severe(n=16) pneumonia and no cardiovascular medical history, without cardiac symptoms, with normal ECG, normal serological cardiac enzyme levels, and discharged > 90 days between May and September 2020. Demographic characteristics, serum cardiac enzymes, and cardiac MRI were obtained. Cardiac function, native T1, ECV and Two-dimensional (2D) strain were quantitatively evaluated and compared with controls (n = 25).The Comparison among the 3 groups were performed using one-way analysis of variance (ANOVA) with Bonferroni corrected post-hoc comparisons(for normal distribution) or Kruskal-Wallis tests with post-hoc pairwise comparisons(for non-normal distribution). Results Forty participants (54±12 years; 24 men) enrolled with a mean time between admission and CMR of 158 ±18 days and discharge and CMR examination of 124 ±17 days. There was no LV and RV size or functional differences among participants recovered from COVID-19 and healthy controls. Only one (3%) participants had positive LGE located at the mid inferior wall. Global ECV values were elevated in both participants recovered from COVID-19 with moderate or severe pneumonia, compared to the healthy controls [median ECV (IQR)], [29.7% (28.0%-32.9%), versus 31.4% (29.3%-34.0%), versus 25.0% (23.7%-26.0%); both p<.001]. The 2D-global LV longitudinal stains (GLS) were reduced in both groups of participants [COVID-19 moderate group,-12.5%(-10.7%--15.5%), COVID-19 severe group, -12.5%(-8.7%--15.4%) compared to healthy control group -15.4%(-14.6%-17.6%), p=.002 and p=.001, respectively]. Conclusion CMR myocardial tissue and strain imaging parameters suggest that a proportion of participants recovered from COVID-19 had subclinical myocardial abnormalities detectable months after recovery.