. Author manuscript; available in PMC: 2012 Dec 19.

Published in final edited form as: Am J Cardiol. 2012 Jan 14;109(7):1066–1072. doi: 10.1016/j.amjcard.2011.11.042

Table 4.

Differences in key sub-maximal exercise gas exchange data between the controls and pulmonary arterial hypertension groups.

Variable	Control (n = 25)	PAH - WHO I/II (n = 27)	PAH - WHO III/IV (n = 13)
Breathing Efficiency	29 ± 4	35 ± 8^*	48 ± 8^*^†
End-tidal CO₂ @ end exercise (mmHg)	40 ± 3	34 ± 6^*	26 ± 5^*^†
Oxygen Saturation @ end exercise (%)	94 ± 2	90 ± 4^*	88 ± 6^*
Oxygen Pulse @ end exercise	11.8 ± 3.1	9.5 ± 3.0^*	6.9 ± 2.4^*^†

Data are presented as mean ± standard deviation.

Significant differences between control and pulmonary arterial hypertension groups (p < 0.05).

^†

Significant differences between the pulmonary arterial hypertension groups (p < 0.05).