Interaction between the rigt heart ventricle and its arterial load: a quantitative solution.

Piene and Sund (Cardiovasc. Res., 1980) have recently demonstrated that the performance of the ventricle can be expressed by relating the principal variables pressure (P), volume (V), and time after onset of contraction (t): P = function (V,t). The function can be mapped experimentally as a three-dimensional surface, denoted the PVt surface, and can thereafter be approximated by an empirical equation. The vascular load of the ventricle is defined by the arterial input impedance vs. frequency graph, Z(f), which can be converted to the time domain by inverse Fourier transformation. This report describes how flow and pressure generated by the ventricle can be calculated when the independent expressions for the ventricle and for the load are given. The method is applied on right ventricular contractions of isolated cat hearts, and excellent fit between calculated and observed flow and pressure curves was obtained.