Common cardiopulmonary exercise test findings in patients with pulmonary arterial hypertension
| Reduced parameters | Increased parameters |
| Peak V′O2 | VD/VT during exercise (>30%) |
| WR | PA–aO2 differences during exercise (up to 45 mmHg or over) |
| O2 pulse | |
| V′O2/WR | |
| PETCO2 at rest | |
| PETCO2 at AT | |
| O2 saturation during exercise (drop >3% without PaCO2 rise) |
V′O2: oxygen uptake; VD: dead space volume; VT: tidal volume; WR: work rate; PA–aO2: alveolar–arterial oxygen tension difference; PETCO2: end-tidal carbon dioxide tension; AT: anaerobic threshold; PaCO2: arterial carbon dioxide tension.