Roles of periodic breathing and isocapnic buffering period during exercise in heart failure

Figures

• 

  Figure 1.. Ventilation, oxygen consumption (VO2) and minute ventilation (VE)/carbon dioxide production (VCO2) and derived parameter changes during exercise. The isocapnic buffering period is identified between the anaerobic threshold (AT) and the respiratory compensation point (RCP). Reproduced from Carriere et al.17 with permission.

• 

  Figure 2.. Measurements of near infrared spectroscopy (NIRS) data at rest in a patient with periodic breathing at rest. Fluctuation of oxygenated haemoglobin (HBO2), de-oxygenated haemoglobin (HB) and total haemoglobin (tHB) are reported. The cycle length is approximately 130 seconds.

• 

  Figure 3.. Survival and presence of exercise oscillatory ventilation in patients with heart failure with reduced ejection fraction (HFrEF) and in patients with heart failure with mid-range ejection fraction (HFmrEF). Kaplan–Meier survival curves of study endpoint (cardiovascular death, urgent heart transplant or left ventricular assist device (LVAD) implantation) stratified according to the presence or absence of exercise oscillatory ventilation (EOV+ and EOV–) in patients with HFrEF and in patients with HFmrEF. Comparison among the groups (HFmrEF EOV– vs. HFmrEF EOV+: P = 0.020, χ2 = 5.4; HFmrEF EOV– vs. HFrEF EOV–: P = 0.000, χ2 = 31.1; HFmrEF EOV– vs. HFrEF EOV+: P = 0.000; χ2 = 75.9; HFmrEF EOV+ vs. HFrEF EOV–: P = 0.280, χ2 = 1.17; HFmrEF EOV+ vs. HFrEF EOV+: P = 0.000, χ2 = 29.7; HFrEF EOV– vs. HFrEF EOV+: P = 0.000; χ2 = 9.9). Reproduced from Rovai et al.41 with permission.

• 

  Figure 4.. Five-year survival, assessed by the composite of cardiovascular death, urgent heart transplantation (HT) and left ventricular assist device (LVAD) in groups 1 (neither anaerobic threshold (AT) nor respiratory compensation point (RCP) detectable), 2 (detectable AT but no RCP) and 3 (both AT and RCP detectable), respectively. Reproduced from Carriere et al.42 with permission.