  Computer models of cardiac electro-mechanics (EM) show promise as an
effective means for quantitative analysis of clinical data and, potentially,
for predicting therapeutic responses.realize such advanced applications
methodological key challenges must be addressed. Enhanced computational
efficiency and robustness is crucial to facilitate, within tractable time
frames, model personalization, the simulation of prolonged observation periods
under a broad range of conditions, and physiological completeness encompassing
therapy-relevant mechanisms is needed to endow models with predictive
capabilities beyond the mere replication of observations. Here, we introduce a
universal feature-complete cardiac EM modeling framework that builds on a
flexible method for coupling a 3D model of bi-ventricular EM to the
physiologically comprehensive 0D CircAdapt model representing atrial mechanics
and closed-loop circulation. A detailed mathematical description is given and
efficiency, robustness, and accuracy of numerical scheme and solver
implementation are evaluated. After parameterization and stabilization of the
coupled 3D-0D model to a limit cycle under baseline conditions, the model's
ability to replicate physiological behaviors is demonstrated, by simulating the
transient response to alterations in loading conditions and contractility, as
induced by experimental protocols used for assessing systolic and diastolic
ventricular properties. Mechanistic completeness and computational efficiency
of this novel model render advanced applications geared towards predicting
acute outcomes of EM therapies feasible.
