Interventricular coupling coefficients in a thick shell model of passive cardiac chamber deformation

Mechanical interplay between the adjacent ventricles is one of the principal modulators of physiopathological heart function, and the underlying mechanisms of interaction are only partially understood, hence hampering clinically useful interpretation of imaging data. In order to characterize the influence of chamber geometry on ventricular coupling, the ventricles and septum are modeled as portions of ellipsoidal shells, and configuration is derived as a function of pressure gradients by combining shell element equilibrium equations through static boundary conditions applied at the sulcus. Diastolic volume (v) surfaces are calculated as a function of pressure (p), contralateral pressure (clp) and intrathoracic pressure (pt) and match literature data where available. Ventricular interaction is characterized in terms of partial derivatives in v-p-clp-pt space both under physiological and altered (selectively stiffened walls) conditions. The model allows prediction of diastolic ventricular v-p-clp-pt interplay in a variety of physiopathological circumstances. © International Federation for Medical and Biological Engineering 2008