Mid- and long-term atrio-ventricular mechanics in children after recovery from asymptomatic or mildly symptomatic SARS-CoV-2 infection
Authors: Sabatino J , Sirico D , Di Chiara C , Pogacnik P , Di Candia A , Bonfante F , Dona D , Costenaro P , Fumanelli J , Reffo E , Castaldi B , Biffanti R , Cerutti A , Giaquinto C , Di Salvo G 
Published: October 2022

Abstract

Background
Clinical manifestations of children's coronavirus disease-2019 (COVID-19) were initially considered less severe compared with adult patients. However, there is now increasing evidence of a “long-tail” of COVID-19 related symptoms lasting for several months after recovery from the acute infection. Long COVID-19-related symptoms and mechanisms are poorly characterized and understood, with several phenotypes reported, often driven by long-term tissue damage (such as lung, heart and brain) and pathological inflammation due to viral persistence and/or immune deregulation.

Purpose
The objective of this study was to evaluate atrio-ventricular mechanics, by means of two-dimensional speckle-tracking echocardiography, in previously healthy children recovered from asymptomatic or mildly symptomatic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in a long-term follow-up.

Methods
We analysed a cohort of 157 paediatric patients, mean age 7±4 years, who had a confirmed diagnosis of SARS-CoV-2 infection and were asymptomatic or mildly symptomatic for COVID-19. Patients underwent standard transthoracic echocardiogram and speckle tracking echocardiographic study 148±68 days after diagnosis. One hundred seven age, sex, and body surface area comparable healthy subjects were used as control group.

Results
Left ventricular ejection fraction was within normal limits in postCOVID-19 cases and CTRL with no significant differences between the two groups (postCOVID-19: 65.6±4% vs CTRL: 65.0±5%, p=0.182).
Left ventricular (LV) global longitudinal strain (postCOVID-19: −20.5±2.9%; CTRL: −21.8±1.7%; p&lt;0.001) was significantly reduced in cases compared with CTRLs. An amount of 11 (7%) postCOVID-19 cases showed impaired GLS values &lt; −17% and 95 subjects (60%) presented with a strain lower than −16% in more than 2 segments. These subjects did not show any difference regarding symptoms or serological findings. Moreover, GLS was significantly reduced in children with disease's onset during the second wave of COVID-19 pandemic, compared with those during the first wave (second wave: −20.2±2.6%; first wave: −21.2±3.4%; p=0.048). Finally, peak left atrial systolic strain was within the normal range in the postCOVID-19 group with no significant differences compared to CTRL (postCOVID-19: 49.1±12%; CTRL: 49.5±18%).

Conclusions
SARS-CoV-2 infection may affect left ventricular deformation in children despite an asymptomatic or only mildly symptomatic acute illness. Our data show an amount of 60% of children, recovering from asymptomatic or mildly symptomatic COVID-19, with still mild subclinical systolic cardiac impairment in the mid- and long-term follow-up after the infection. This subtle impairment was seen to be worse in children recovering from the second wave of COVID-19 compared to the first one.
A follow-up is needed to verify the reversibility of these alterations and their impact on long-term outcomes.

Funding Acknowledgement
Type of funding sources: None.