Table 2.
Basic ventilatory and gas exchange responses at rest and peak exercise
| All | HFrEF | HFpEF | P-value | |
|---|---|---|---|---|
|
|
|
|||
| Rest | N = 59 | N = 32 | N = 27 | |
| V̇O2 (L/min) | 0.24 ± 0.06 | 0.23 ± 0.05 | 0.25 ± 0.07 | 0.97 |
| V̇CO2 (L/min) | 0.21 ± 0.06 | 0.20 ± 0.05 | 0.21 ± 0.07 | 0.99 |
| RER | 0.87 ± 0.10 | 0.88 ± 0.10 | 0.85 ± 0.09 | 0.63 |
| V̇E (L/min) | 8.6 ± 2.7 | 9.0 ± 2.2 | 8.1 ± 3.3 | 0.95 |
| fB (breaths/min) | 17 ± 4 | 17 ± 4 | 16 ± 5 | 0.91 |
| VT (L) | 0.54 ± 0.18 | 0.54 ± 0.16 | 0.53 ± 0.20 | 0.99 |
| V̇E/V̇CO2 | 42 ± 8 | 45 ± 7 | 38 ± 6 | <0.001 |
| PETO2 (mm Hg) | 103 ± 6 | 103 ± 6 | 102 ± 5 | 0.98 |
| PETCO2 (mm Hg) | 35 ± 6 | 33 ± 5 | 39 ± 5 | <0.001 |
| PECO2 (mm Hg) | 21 ± 4 | 20 ± 3 | 23 ± 4 | <0.01 |
| PECO2/PETCO2 | 0.60 ± 0.06 | 0.61 ± 0.06 | 0.60 ± 0.06 | 0.98 |
| Peak exercise | ||||
| Workload, W | 38 ± 11 | 39 ± 11 | 36 ± 12 | 0.39 |
| V̇O2 (L/min) | 0.76 ± 0.22* | 0.70 ± 0.18* | 0.82 ± 0.25* | 0.04 |
| V̇CO2 (L/min) | 0.82 ± 0.23* | 0.77 ± 0.19* | 0.89 ± 0.25* | 0.04 |
| RER | 1.10 ± 0.08* | 1.10 ± 0.09* | 1.10 ± 0.06* | 0.92 |
| V̇E (L/min) | 32 ± 9* | 33 ± 9* | 35 ± 9* | 0.43 |
| fB (breaths/min) | 31 ± 8* | 30 ± 7* | 31 ± 10* | 0.97 |
| VT (L) | 1.08 ± 0.33* | 1.13 ± 0.35* | 1.03 ± 0.31* | 0.43 |
| V̇E/V̇CO2 | 40 ± 10 | 44 ± 10 | 35 ± 7* | <0.001 |
| PETO2 (mm Hg) | 112 ± 7* | 113 ± 7* | 111 ± 6* | 0.62 |
| PETCO2 (mm Hg) | 34 ± 8 | 30 ± 6* | 39 ± 7 | <0.001 |
| PECO2 (mm Hg) | 23 ± 5 | 20 ± 4 | 25 ± 5* | <0.01 |
| PECO2/PETCO2 | 0.68 ± 0.05* | 0.69 ± 0.04* | 0.66 ± 0.06* | 0.14 |
Data are mean ± SD. Oxygen consumption (V̇O2); carbon dioxide output (V̇CO2); respiratory exchange ratio (RER); minute ventilation (V̇E); respiratory rate (fB); tidal volume (VT); end-tidal oxygen (PETO2); end-tidal carbon dioxide (PETCO2); mixed expired carbon dioxide (PECO2).
*
Within group, rest vs. peak exercise, P<0.05. Table P-values and symbols represent significance after Tukey-Kramer post-hoc testing from repeated measures ANOVA models.