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. Author manuscript; available in PMC: 2013 Jun 27.
Published in final edited form as: Cardiol Clin. 2011 Aug;29(3):461–477. doi: 10.1016/j.ccl.2011.06.002

Fig. 4.

Fig. 4

Cardiovascular function assessed by invasive cardiopulmonary exercise testing in patients who have heart failure and normal systolic function (open boxes) and age-matched normal controls (closed boxes). The primary components of the Fick equation for VO2, cardiac output, and A-VO2 difference are shown in panels A and B, respectively. The components of cardiac output, stroke volume, and heart rate are shown in panels C and D. The X-axis is exercise workload in kilopounds/min (kpm); 150 kpm is equivalent to 25 W. (From Kitzman DW, Higginbotham MB, Cobb FR, et al. Exercise intolerance in patients with heart failure and preserved left ventricular systolic function: failure of the Frank-Starling mechanism. J Am Coll Cardiol 1991;17:1065-72; with permission. Copyright © 1991, American College of Cardiology.)