An in silico journey of right ventricular growth and remodelling after pulmonary valve regurgitation

Digital twins of cardiac function are revolutionizing the management of heart diseases. Pulmonary valve regurgitation (PR), a common complication following repair of tetralogy of Fallot, can lead to detrimental effects on right ventricular (RV) function if it persists. Although pulmonary valve replacement can address PR, its long-term effects remain a topic of debate. Despite the importance of RV in overall cardiac function, high-fidelity in-silico models of the right ventricle remain under-explored. In this study, we present a novel mathematical framework to simulate RV growth and remodelling in response to acute PR, along with long-term structural and functional adaptations, and reversible recovery post-intervention. We employ a subject-specific bi-ventricular model integrated with a lumped systemic circulation model, where myocardial mechanics are decomposed into passive and active components, and myocardial growth and remodelling are modelled through a kinematic approach with updated references constrained by biological limits. This framework allows us to model RV response to acute and chronic PR, and subsequent recovery following clinical intervention. For the first time, we demonstrate that RV pump function can return to normal if myocytes retain sufficient functional and structural reserve before interventions. This work marks a significant step toward the realization of digital twins of the RV, providing a robust, predictive tool for modelling disease progression, intervention outcomes, and myocardial reserve remodelling.