Determinants of cardiac output in health and heart failure

Figures

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  FIGURE 1. (a) The relationship between cardiac output (Q˙C) and oxygen uptake (V˙O2) during exercise. Normally, Q˙C increases by 5–6 L/min for every 1 L/min increase in V˙O2. (b) Q˙C:V˙O2 slope among healthy individuals (n = 15) undergoing invasive cardiopulmonary exercise testing (CPET). Continuous black lines represent individual data. Continuous red‐line indicates group‐averaged data with mean slope of 6.0819; (c) Q˙C:V˙O2 slope among patients with HFrEF (n = 36) undergoing invasive CPET. Dashed black lines represent individual data. Continuous blue‐line indicates group‐averaged data with mean slope of 5.7993. See text for further details. Data provided from laboratory of senior author (W.K.C.). HFrEF, HF with reduced ejection fraction.

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  FIGURE 2. Example tracings of invasive haemodynamics during a progressive head‐up tilt in a 73‐year‐old female with HFrEF (LVEF 30%). Data obtained from Swan–Ganz catheter demonstrating pulmonary arterial pressure and pulmonary capillary wedge pressure at supine, 30° and 60° head‐up tilt. The increased gravitational gradient associated with tilt leads to reduction in filling pressures. Data provided from senior author's laboratory. HF, heart failure; HFrEF, HF with reduced ejection fraction; LVEF, left ventricular ejection fraction.

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  FIGURE 3. Haemodynamic tracings obtained from a 67‐year‐old man with ischaemic cardiomyopathy (LVEF 23%), undergoing invasive cardiopulmonary exercise testing. Data acquired during rest, two levels of submaximal exercise, as well as peak effort. Data provided by senior author (Edward, Banchs, et al., 2023, Edward, Parker, et al., 2023). BP, blood pressure; LVEF, left ventricular ejection fraction; PAP, pulmonary arterial pressure; PCWP, pulmonary capillary wedge pressure.

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  FIGURE 4. Example tracings of real‐time right ventricular pressure–volume loops during exercise from a healthy individual completing invasive cardiopulmonary exercise testing with a conductance catheter during upright cycle ergometry. Black represents resting loops, red and blue represent two levels of submaximal exercise, and gold represents peak exercise. Data provided by senior author (Cornwell et al., 2020).