Patient-specific Modeling of Cardiac Biomechanics in Repaired Tetralogy of Fallot

Surgical advancements in the management of Tetralogy of Fallot, the most common cyanotic congenital heart defect, have allowed individuals to survive into adulthood. However, most individuals develop pulmonary regurgitation, causing right ventricular volume overload, dilatation, and possible dysfunction. These patients require pulmonary valve replacement (PVR), but the timing and indications for the operation are still under investigation. One proposed clinical indicator for PVR is a right ventricular end-diastolic volume index (RVEDVI) greater than 150 mL/m2, though this threshold value is somewhat controversial. Because diastolic fiber strains have been found to correlate well with ventricular remodeling in response to volume overload, a correlation may also exist between diastolic fiber strain and reverse remodeling after alleviation of volume overload. In this thesis, biventricular image-based computational models were developed to test the hypothesis that RVEDVI correlates with post-PVR regional diastolic fiber strains in the right ventricle. Two computational models with RVEDVIs of 170 mL/m2 and 115 mL/m2 were developed, and each model underwent full-beat simulation before and after virtual PVR. Preliminary findings suggest that RVEDVI may in fact correlate negatively with post-PVR regional diastolic fiber strains of repaired ToF patients, particularly in regions of the right ventricular free wall adjacent to the septum