Exercise oscillatory ventilation and prognosis in heart failure patients with reduced and mid-range ejection fraction

Aims: Exercise oscillatory ventilation (EOV) is a pivotal cardiopulmonary exercise test parameter for the prognostic evaluation of patients with chronic heart failure (HF). It has been described in patients with HF with reduced ejection fraction (<40%, HFrEF) and with HF with preserved ejection fraction (>50%, HFpEF), but no data are available for patients with HF with mid-range ejection fraction (40–49%, HFmrEF). The aim of the study was to evaluate the prognostic role of EOV in HFmrEF patients. Methods and results: We analysed 1239 patients with HFmrEF and 4482 patients with HFrEF, enrolled in the MECKI score database, with a 2-year follow-up. The study endpoint was the composite of cardiovascular death, urgent heart transplant, and ventricular assist device implantation. We identified EOV in 968 cases (16% and 17% of cases in HFmrEF and HFrEF,. respectively). HFrEF EOV+ patients were significantly older, and their parameters suggested a more severe HF than HFrEF EOV− patients. A similar behaviour was found in HFmrEF EOV+ vs. EOV− patients. Kaplan–Meier analysis, irrespective of ejection fraction, showed that EOV is associated with a worse survival, and that patients with HFrEF and HFmrEF EOV+ had a significantly worse outcome than the EOV− of the same ejection fraction groups. EOV-associated survival differences in HFmrEF patients started after 18 months of follow-up. Conclusion: Exercise oscillatory ventilation has a similar prevalence and ominous prognostic value in both HFmrEF and HFrEF patients, indicating a group of patients in need of a more intensive follow-up and a more aggressive therapy. In HFmrEF, the survival curves between EOV+ and EOV− patients diverged only after 18 months.