In the graph at upper right, the response shown by the dotted line illustrates the effect of
Right atrial pressure $(\mathrm{mm} \mathrm{Hg})$ or end-diastolic volume (L)

Question

In the graph at upper right, the response shown by the dotted line illustrates the effect of
 Right atrial pressure $(\mathrm{mm} \mathrm{Hg})$ or end-diastolic volume (L)

Quizplus · Accepted Answer

[Chapter 3, IV F 3 a; Figures 3.8 and 3.12]. A downward shift of the cardiac output curve is consistent with decreased myocardial contractility (negative inotropism); for any right atrial pressure or end-diastolic volume, the force of contraction is decreased. Digitalis, a positive inotropic agent, would produce an upward shift of the cardiac output curve. Changes in blood volume alter the venous return curve rather than the cardiac output curve. Changes in total peripheral resistance (TPR) alter both the cardiac output and venous return curves.

In the Graph at Upper Right, the Response Shown by the Dotted