Right Ventricular Remodeling in Repaired Tetralogy of Fallot: Imaging, Arrhythmia Risk, and Timing of Pulmonary Valve Replacement

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and advances in surgical repair have enabled survival into adulthood for most patients. However, long-term survival after repair is frequently complicated by progressive right ventricular (RV) remodeling driven by chronic pulmonary regurgitation, residual RV outflow tract obstruction, myocardial fibrosis, and electromechanical dyssynchrony. RV remodeling in repaired TOF (rTOF) is a dynamic process characterized by RV dilatation, altered geometry, declining systolic and diastolic function, interventricular interaction, and arrhythmogenic substrate formation. These structural and electrophysiologic changes underpin the late burden of ventricular arrhythmias, heart failure, and sudden cardiac death in this population. Multimodality imaging has become central to surveillance and risk stratification, with echocardiography providing longitudinal bedside assessment, cardiovascular magnetic resonance serving as the reference standard for RV volumes and tissue characterization, computed tomography aiding procedural planning, and emerging deformation imaging refining subclinical functional assessment. Pulmonary valve replacement (PVR), whether surgical or transcatheter, remains the principal intervention to reduce pulmonary regurgitation and mitigate RV volume overload, yet the optimal timing of intervention remains controversial. Delayed PVR risks irreversible RV dysfunction and arrhythmia progression, whereas premature intervention may expose patients to additional valve-related reinterventions over a patient's lifetime, emphasizing the importance of optimizing long-term procedural durability. This narrative review synthesizes contemporary evidence on the mechanisms and phenotypes of RV remodeling in rTOF, the role of multimodality imaging in defining adverse remodeling, the relationship between RV structural change and arrhythmia risk, and current concepts guiding the timing of PVR. A precision-based framework integrating imaging, electrophysiology, and clinical trajectory is proposed to optimize longitudinal management in this growing adult congenital population.