Differential impacts of body composition on oxygen kinetics and exercise tolerance of HFrEF and HFpEF patients

Fig. 1. Flowchart of patients.

Fig. 2. Representative responses of (A) O2 uptake (V′O2) and (B) skeletal muscle deoxygenation [HHb] kinetics at the onset of high-intensity exercise in HFrEF (white-circle) and HFpEF (black-circle). (a) note that V′O2 kinetics was slower in HFrEF patients (τ, time constant of the primary component). (b) note that [HHb] kinetics was slower in HFrEF patients ([HHb] values are expressed relative to the amplitude of variation from baseline to the steady-state). TD, time delay; τ, the time constant and MRT (in s) [MRT= =τ + TD). This figure was previously published in abstract format (39).

Fig. 3. Group correlation analysis among HFrEF (white circle) and HFpEF (black circle) patients. (a) A significantly inverse relationship between time to intolerance in response to high-intensity exercise and the τ of the primary component of the on-transient V′O2. (b) A significant positive relationship between an index of the kinetics of microvascular O2 delivery (τ of the primary component of the on-transient V′O2/MRT of the changes in [HHb] and the kinetics of systemic O2 delivery, as estimated by the dynamics of QT (MRT-QT), at the onset of high-intensity exercise. Group correlation analysis among HFrEF (white circle) and HFpEF (black circle) patients. (a) A significant positive relationship between a lean mass percentage (%) and the τ of the primary component of the on-transient V′O2. (b) A significant positive relationship between fat percentage (%) and the τ of the primary component of the on-transient V′O2.

Fig. 4. Mean response time (MRT, sec) of V′O2 and [HHb] measured by near-infrared spectroscopy at the onset of heavy-intensity exercise and index of the kinetics of microvascular O2 delivery (QO2mv) in HFrEF (open bars) and HFpEF (solid bars). MRT = τ + TD, V′O2/MRT- [HHb] (τ of the primary component of the on-transient V′O2/MRT of the changes in [HHb]). V′O2 = O2 uptake, [HHb] = deoxy-hemoglobin concentration. Note that the dynamics of V′O2 were slower in HFrEF; in contrast, they presented with faster [HHb] kinetics than the HFpEF. Values are means (SD). *P < 0.05 for between-group comparisons.

Fig. 5. Central illustration kinetics. Oxygen uptake (V′O2), heart failure (HF) patients with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF).