Objectives: Many children diagnosed with COVID-19 infections did not require hospitalisation. Our objective was to analyse electrocardiographic changes in children with asymptomatic, mild or moderate COVID-19 who did not require hospitalisation Methods: All children are seen in a paediatric cardiology clinic who had asymptomatic, mild or moderate COVID-19 that did not require hospitalisation and had at least one electrocardiogram after their diagnosis were included in this retrospective analysis. Records were reviewed to determine COVID-19 disease severity and presence of Long COVID. Rhythm assessment, atrial enlargement, ventricular hypertrophy, PR/QRS/QT interval duration and ST-T wave abnormalities were analysed by a paediatric electrophysiologist. Clinically ordered echocardiograms were reviewed for signs of myopericarditis (left ventricular ejection fraction and pericardial effusion) on any subject with an electrocardiographic abnormality. Results: Of the 82 children meeting inclusion criteria (14.4 years, range 1–18 years, 57% male), 17 patients (21%) demonstrated electrocardiographic changes. Ten patients (12%) had electrocardiogram of borderline significance, which included isolated mild PR prolongation or mild repolarisation abnormalities. The other seven patients (9%) had concerning electrocardiographic findings consisting of more significant repolarisation abnormalities. None of the patients with an abnormal electrocardiogram revealed any echocardiographic abnormality. All abnormal electrocardiograms normalised over time except in two cases. Across the entire cohort, greater COVID-19 disease severity and long COVID were not associated with electrocardiographic abnormalities. Conclusions: Electrocardiographic abnormalities are present in a minority of children with an asymptomatic, mild or moderate COVID-19 infection. Many of these changes resolved over time and no evidence of myopericarditis was present on echocardiography.

Aim: Patient-specific fluid dynamic simulation of pulmonary arteries can be a valuable tool in pre-procedural planning. Materials & methods: For three patients, soft, deformable models of the pulmonary arteries were 3D printed from cardiac magnetic resonance data. In vitro hemodynamics were replicated using a gear flow pump, 40% glycerol solution and a physical Windkessel module. The pulmonary pressures were compared with patient cardiac catheterization pressure. Results: The pulmonary artery pressures and flow volumes had an adequate goodness of fit except for pulmonary pressures in patient 2. Conclusion: Cardiac magnetic resonance angiogram and flow volume data can be leveraged to generate a patient-specific 3D model and reproduce in vivo hemodynamics by means of in vitro simulation.