Analysis and Simulation of the Left Ventricular Response to Autonomic Nervous Activity

Statistical experimental design techniques and a hybrid computer simulation have been used to quantitate the left ventricular systolic pressure (LVSP) response to simultaneous stimulation of both autonomic divisions in the isolated, isovolumic heart. A quadratic regression response surface was derived which clearly indicates the extent of the vagal–sympathetic amplitude interaction. Dynamically, the vagal-LVSP response is essentially first order for increasing and decreasing nervous activity; the sympathetic-LVSP response is well represented by parallel first and second order components for increasing activity, and parallel first order components for decreasing activity.