Echocardiographic Assessment of Cardiac Function and Reserve Under Exercise in Post-COVID-19 Children: A Prospective Cross-sectional Study.

Background: Cardiovascular impairment has been observed in adults with coronavirus disease 2019 (COVID-19), even in those with mild symptoms. Physical activity can reveal subtle cardiovascular dysfunction that is not apparent at rest. However, there are limited data on cardiovascular function in children and adolescents after the COVID-19 infection. This study aimed to assess cardiovascular function in paediatric and adolescent populations with a history of COVID-19 infection and controls by conducting 2-dimensional transthoracic echocardiography at rest (TTE-R) and exercise stress echocardiography (ESE). Methods: We conducted TTE-R, including speckle tracking strain analysis of both ventricles, on 100 individuals (median age 12.3 years, 82% male), divided into 2 groups: 73 adolescents with COVID-19 infection and 27 controls. A subset of male participants (40 cases, 15 controls) underwent ESE combined with a cardiopulmonary exercise test (CPET-ESE) to examine the relationship between cardiovascular parameters and contractile reserve. Myocardial contractile reserve was evaluated by measuring the maximum increase in strain values during exercise. Results: At rest, no signs of myocardial injury or inflammation were observed. Right and left ventricular contractility in the infected group were clinically equivalent to those in the controls. During CPET-ESE, peak oxygen consumption was similar between the infected and control groups. Furthermore, contractile reserve under exercise was similar in both groups. Conclusions: We found no significant differences in left ventricular systolic and diastolic function and right ventricle systolic function evaluated by TTE-R between participants with a history of mild COVID-19 infection and controls. ESE provided insights for post-COVID-19 young people resuming activities and sports.