Figure 3.

Relative weight of cardiac output and arteriovenous oxygen difference in determining oxygen consumption at rest, during passive leg raising and at peak exercise. Dotted lines represent oxygen consumption isophlets, i.e., cardiac output and arteriovenous oxygen difference coordinates whose product is a given oxygen consumption, at rest, during passive leg raising, and at peak exercise. C(a-v)O₂, arteriovenous oxygen difference; CO, cardiac output; HFpEF, heart failure with preserved ejection fraction; PLR, passive leg raising; STR, secondary tricuspid regurgitation.