Prognostic value of timing and duration characteristics of exercise oscillatory ventilation in patients with heart failure

Background: Exercise oscillatory ventilation (EOV) occurs in a sub-group of patients with increased heart failure (HF) severity and poorer prognosis. The purpose of this investigation was to examine the prognostic value of the largest ventilatory oscillation characteristics in HF patients. Methods: One hundred fifty-four subjects diagnosed with HF underwent cardiopulmonary exercise testing. Subjects with EOV were then divided into two sub-groups: (1) largest ventilatory oscillation during the first half of exercise with an oscillation width ≥30 seconds; and (2) largest ventilatory oscillation during the second half of exercise or an oscillation width <30 seconds. Subjects were tracked for major cardiac events after the exercise test. Results: The fifty-five subjects (35.7%) in the overall group demonstrating EOV during the exercise test were at significantly higher risk for adverse events (hazard ratio = 3.0, 95% confidence interval 1.6 to 5.5, p < 0.001). The prognostic value of this ventilatory phenomenon improved when only subjects with the largest ventilatory oscillation during the first half of exercise with an oscillation width ≥30 seconds were defined as having EOV (hazard ratio = 3.6, 95% confidence interval 1.6 to 7.9, p = 0.002). Conclusions: In this study we found that the characteristics of the largest oscillatory ventilation provide valuable prognostic information in patients with EOV.