A More Quantitative Analysis of Cardiac Output Regulation

A More Quantitative Analysis of Cardiac Output Regulation

Our discussion of cardiac output regulation thus far is adequate for understanding the factors that control cardiac output in most simple conditions. However, to understand cardiac output regulation in especially stressful situations, such as the extremes of exercise, cardiac failure, and circulatory shock, a more complex quantitative analysis is presented in the following sections.

To perform the more quantitative analysis, it is nec-essary to distinguish separately the two primary factors concerned with cardiac output regulation: (1) the pumping ability of the heart, as represented by cardiacoutput curves, and (2) the peripheral factors that affectflow of blood from the veins into the heart, as repre-sented by venous return curves. Then one can put these curves together in a quantitative way to show how they interact with each other to determine cardiac output, venous return, and right atrial pressure at the same time.