Exercise oscillatory ventilation in heart failure and in pulmonary arterial hypertension

Background: Patients with pulmonary arterial hypertension (PAH) and with heart failure (HF) have increased ventilatory responses to exercise in proportion to disease severity. Exercise-associated oscillatory ventilation (EOV) predicts poor outcome in HF. Whether EOV occurs in PAH is unknown. Methods: We analyzed the initial cardiopulmonary exercise tests (CPETs) and right heart catheterization data of 109 patients with PAH and in 107 patients with HF consecutively referred to our center. Results: The PAH patients were aged 54 ± 16 years and their NYHA functional class was 2.8 ± 0.5. The HF patients were aged 53 ± 13 years and NYHA 2.4 ± 0.6. Hemodynamic data were obtained in only 36 of them. The patients with PAH compared to those with HF had a lower peak VO2 (13 ± 5 vs 17 ± 5 mL/kg/min, p < 0.001) and a higher ventilatory equivalent for CO2 (VE/VCO2) slope (55 ± 21 vs 34 ± 7, p < 0.001). Mean pulmonary artery pressure was higher (50 ± 10 vs 29 ± 11 mmHg) and wedge pressure lower (10 ± 3 vs 19 ± 5 mm Hg) in PAH patients, but cardiac output was not different (4.0 ± 1.3 vs 4.2 ± 1.2 L/min). EOV was present in 22 patients (21%) with HF and in no patient with PAH. Conclusions: Patients with PAH compared to HF with slightly better functional class have a lower aerobic exercise capacity and higher ventilatory responses, but no EOV. An increase in pulmonary artery wedge pressure rather than a low cardiac output may be necessary condition of EOV in HF.