Mathematical simulations of paediatric haemodynamics in isolated ventricular septal defect

Computer modelling of the cardiovascular system has the potential to revolutionize personalized medical care. This is especially promising for congenital heart defects, such as ventricular septal defect (VSD), a hole between the two ventricles of the heart. However, relatively few studies have built computer models for VSD, nor have they considered how natural adaptation to the cardiovascular system with age might interact with the presence of a small-, medium- or large-sized VSD. Here, we combine a lumped-parameter model of the cardiovascular system with two key modelling components: a size-dependent resistance dictating shunt flow between the two ventricles and age-dependent scaling relationships for the systemic and pulmonary circulations. Our results provide insight into changes in haemodynamic conditions with various VSD sizes. We investigate the combined effects of VSD size, vascular parameters and age, showing distinct differences with these three factors. This study lays the necessary foundation for studying VSD and towards building digital shadows and digital twins for managing VSD in paediatrics.