A non-invasive method to calculate parameters of non-linear end-systolic pressure-volume relation.

摘要

The relation between pressure P_m and volume V_m in the ventricles near end-systole when the cardiac muscle reaches its maximum state of activation (known as the end-systolic pressure-volume relation (ESPVR)) has been the object of extensive studies over the past years [1-11]. A non-invasive method to calculate some of the parameters of the non-linear ESPVR is presented in this communication. In a model used by the author in [5-8] the left ventricle is represented as a thick-walled cylinder contracting symmetrically as shown in Fig. 1. The symmetrical helical structure of the myocardial fibres will generate a radial active force per unit volume of the myocardium Dr(r). The active pressure developed by the force Dr(r) on the inner surface of the myocardium (endocardium) can de expressed as: