Personalized biventricular mechanics and sensitivity to model morphology.

We present a computational framework for patient-specific modeling of biventricular (BiV) mechanics based on standard clinical data, including electrocardiogram (ECG), cuff blood pressure, and ECG-gated computed tomography angiography (CTA) imaging. The model is coupled to a closed-loop lumped-parameter network (LPN) circulatory model and incorporates rule-based fiber architecture, as well as spatially varying epicardial boundary conditions to approximate surrounding tissue support. Model parameters are personalized through a multistep procedure that sequentially tunes circulatory dynamics, passive mechanics, and active contraction. The resulting personalized BiV model reproduces the clinical hemodynamic targets used during calibration and demonstrates reasonable agreement with image-based myocardial deformation metrics that were not directly included in the parameter-tuning process. We then use this model as a baseline to assess the impact of two commonly used anatomical simplifications: a truncated BiV (t-BiV) model cut at the basal plane and a left ventricle-only (LV) model. With all parameters held fixed, the LV model exhibits similar global pressure/volume behavior compared to the BiV model, despite moderate differences in regional deformation. In contrast, the t-BiV model produces substantial differences from the full BiV baseline in both global function and local myocardial mechanics. While drawn from a single-patient case study, these results demonstrate that anatomical simplifications can substantially affect model outputs, motivating further investigation across larger cohorts, disease states, and model complexity.