Non-linear pressure-volume relation in left ventricle.

A thick-walled elastic cylinder contracting symmetrically is used as a model for the myocardium. The active force generated by the myocardium during systolic contraction is represented by body force (force/unit volume of myocardium). A mathematical formalism previously developed and based on large deformation analysis is used to derive a quadratic equation to represent the non-linear pressure volume (P-V) relation in the left ventricle in the Suga-Sagawa model. Experimental application of the results obtained confirms the consistency of the mathematical formalism developed to describe the P-V curve in the Suga-Sagawa model.