Cardiovascular phenotyping of children and adolescents with post-COVID syndrome (PCS) at initial diagnosis - a prospective observational single-center study

Background Post-COVID Syndrome (PCS) is an emerging, highly relevant topic in public health as it negatively affects quality of life and educational/work performance at all ages. To date, there is hardly any robust data on cardiac function in PCS (Long-COVID) available, particularly not in children and adolescents. The aim of this study was to conduct deep cardiovascular phenotyping in pediatric patients with PCS at initial presentation using cardiac MRI and echocardiography, including strain/tissue tracking analysis. Methods Prospective, single center cohort study at Hannover Medical School, Germany (10207_BO_K_2022). PCS was defined as follows: persistent symptoms such as reduced physical performance, poor concentration, mood symptoms, headaches, sleep disorders and dysosmia, for at least 12 weeks after PCR-confirmed SARS-CoV-2 infection. A total of 100 pediatric patients (age 7–18 years, 56 female) and 20 age/gender matched healthy controls (age 8–18 years, 12 female) were enrolled between 03/2022 and 11/2023. Data collection consisted of 12-lead electrocardiogram (ECG), protocol-driven echocardiography (Echo; Philips EPIQ 7 ultrasound system, Philips Medical Systems), including tissue Doppler Echo and biventricular strain analysis (TOMTEC, Philips). 42 of the 100 PCS patients (age 9–18 years, 26 female) and 28 age/gender matched healthy controls (age 8–18 years, 14 female) received comprehensive cardiac magnetic resonance imaging (CMR; 3.0 T MRI system Magnetom Vida, Siemens Healthineers), including cine mass/volumes quantification in short axis (SAX) and tissue tracking (strain) analysis of the RV and LV (cvi 42). Laboratory studies included serum NTproBNP and Troponin c. Data are presented as mean ± SEM. Results CMR-derived RV global radial strain (RVGRS) (22.6 ± 1.00% vs. 27.1 ± 1.13%; p = 0.003), and RV global circumferential strain (RVGCS) (−13.5 ± 0.55 vs. −15.2 ± 0.51%; p = 0.045) were significantly decreased in PCS vs. CON. Children with PCS also tended to have mildly reduced RVEF (50.9 ± 0.80 vs. 53.5 ± 0.66%; p = 0.259). RV mass index was increased in PCS compared to CON (19.06 ± 0.47 vs. 16.4 ± 0.53 g/m 2 ; p = 0.0002), though in normal range referred to age-appropriate normal values. In contrast, CMR-derived LV variables (LVEF, LVEDV, LVESV, LV mass), including tissue tracking (strain) analysis (LVGLS, LVGCS, LVGRS), revealed similar values in PCS and control subjects. ECG and Echo data analysis did not show significant differences in PCS vs. CON. Conclusion PCS is associated with decreased CMR-based radial and circumferential RV contractility (RVGRS, RVGCS) and slightly increased RV mass in children with PCS compared to healthy, age/gender matched controls. In contrast, LV contractility (strain) and mass were not affected. CMR feature tracking (strain) appears to be more sensitive than echocardiographic strain analysis. Whether the aforementioned RV alterations are causal for the reported cardiopulmonary exercise limitations in pediatric PCS is unknown, and should be investigated further.