Figure 2.

Agreement in multiple studies describing the near-linear relationship between increases in cardiac output and pulmonary arterial pressures (PAPs). Data are from two echocardiographic studies^24,26 and one invasive study²⁷ demonstrating a consistent relationship between increases in PAPs and cardiac output. Although there were methodological differences between the studies, all three converge on an approximately linear increase of 1.5 mmHg in mean PAP (mPAP) for every 1-L increase in cardiac output. As demonstrated by La Gerche et al.,²⁶ this relationship is similar in the healthy pulmonary circulation of nonathletes and athletes, such that the greater increases in PAPs are determined solely by cardiac output. Lewis et al.²⁷ observed a steeper relationship in heart failure patients than in healthy controls. Figures are reproduced with permission.