FIGURE 1.

Pathophysiology of high cardiac output states. The cardiac output is the volume of blood ejected each minute by a ventricle, and the product of stroke volume, and heart rate/minute. Systemic vascular resistance is defined by $\frac{\mathrm{m}\mathrm{e}\mathrm{a}\mathrm{n}\mathrm{}\mathrm{\hspace{0.17em}}\mathrm{a}\mathrm{r}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{i}\mathrm{a}\mathrm{l}\mathrm{}\mathrm{\hspace{0.17em}}\mathrm{p}\mathrm{r}\mathrm{e}\mathrm{s}\mathrm{s}\mathrm{u}\mathrm{r}\mathrm{e}\mathrm{}\mathrm{-}\mathrm{m}\mathrm{e}\mathrm{a}\mathrm{n}\mathrm{}\mathrm{\hspace{0.17em}}\mathrm{\hspace{0.17em}}\mathrm{\hspace{0.17em}}\mathrm{r}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{}\mathrm{\hspace{0.17em}}\mathrm{\hspace{0.17em}}\mathrm{a}\mathrm{t}\mathrm{r}\mathrm{i}\mathrm{a}\mathrm{l}\mathrm{}\mathrm{\hspace{0.17em}}\mathrm{\hspace{0.17em}}\mathrm{p}\mathrm{r}\mathrm{e}\mathrm{s}\mathrm{s}\mathrm{u}\mathrm{r}\mathrm{e}}{\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{i}\mathrm{a}\mathrm{c}\mathrm{}\mathrm{\hspace{0.17em}}\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{p}\mathrm{u}\mathrm{t}}$. For further details of clinical states that reduce systemic vascular resistance, see Anand et al., 1993; Anand and Florea, 2001; Mehta and Dubrey, 2009. Abbreviations: RAAS, renin–angiotensin–aldosterone system. Note the potential positive feedback loops influencing HHT vascular structures.