Cardiopulmonary exercise testing (CPX) parameters, muscle strength and heart failure symptoms at baseline and 12 weeks
| Non-CR group (n=22) | CR group (n=17) | Between-group p value | |||||
|---|---|---|---|---|---|---|---|
| Baseline | 12 weeks | Within-group p value | Baseline | 12 weeks | Within-group p value | ||
| Peak respiratory exchange ratio | 1.25±0.10 | 1.23±0.10 | 0.18 | 1.32±0.11 | 1.31±0.10 | 0.57 | 0.10 |
| Peak WR (W) | 81±19 | 82±23 | 0.49 | 85±23 | 97±27 | <0.01 | <0.01 |
| Peak VO2 (mL/min/kg) | 17.8±2.6 | 18.1±3.4 | 0.45 | 17.4±2.6 | 19.1±3.5 | <0.01 | <0.01 |
| Peak VO2% predicted (%) | 69.7±12.3 | 70.9±13.5 | 0.41 | 70.7±9.4 | 78.2±12.8 | <0.01 | <0.01 |
| VO2 at AT (mL/min/kg)* | 10.8±1.6 | 11.4±2.7 | 0.12 | 10.2±1.6 | 10.8±2.2 | 0.25 | 0.98 |
| VO2 at AT % predicted (%)* | 61.6±10.4 | 65.6±15.3 | 0.09 | 61.7±10.6 | 65.6±11.9 | 0.24 | 0.99 |
| Resting heart rate (beats/min) | 80±14 | 80±16 | 0.79 | 75±12 | 75±11 | 0.71 | 0.45 |
| Peak heart rate (beats/min) | 141±25 | 141±26 | 0.66 | 145±15 | 147±15 | 0.31 | 0.73 |
| Δ VO2/Δ WR (mL/min/W) | 8.2±1.3 | 8.0±1.5 | 0.47 | 7.6±1.4 | 7.6±1.9 | 0.88 | 0.75 |
| Oxygen pulse (mL/min/beat) | 6.9±1.7 | 7.0±1.7 | 0.39 | 6.6±1.5 | 7.3±1.7 | <0.01 | 0.01 |
| VE-VCO2 slope | 37.6±6.8 | 36.6±6.5 | 0.33 | 42.1±10.2 | 39.7±9.8 | 0.17 | 0.94 |
| Lowest SpO2 (%) | 90.2±4.7 | 91.3±3.9 | 0.09 | 89.0±5.1 | 89.2±4.8 | 0.80 | 0.21 |
| Muscle strength | |||||||
| Forearm (kg) | NA | NA | NA | 28 (23–37) | 27 (25–37) | 0.74# | NA |
| Quadriceps (kg) | NA | NA | NA | 26.4±8.1 | 29.1±8.1 | <0.01 | NA |
| Other clinical parameters | n=24 | n=24 | n=17 | n=17 | |||
| WHO-FC (I/II/III/IV, mean) | 1/21/2/0, 2.0 | 4/19/1/0, 1.9 | 0.05# | 0/14/3/0, 2.2 | 4/12/1/0, 1.8 | 0.01# | 0.28## |
| 6-min walk distance (m) | 468±102 | 476±97 | 0.43 | 498±96 | 510±98 | 0.10 | 0.53 |
Results are expressed as mean±SD or median (25% and 75% centile) unless otherwise indicated. Within-group p values from #Wilcoxon signed-rank tests or otherwise paired t tests. Between-group p values from ##ordinal logistic regression analysis or otherwise ANCOVA.
*21 patients in the non-CR group and 12 patients in the CR group for this data point, because we could not accurately determine the AT level in preinterventional and/or postinterventional CPX in 6 patients due to ventilatory oscillation-like changes or increased ventilatory drives even at rest.
AT, anaerobic threshold; CR, cardiac rehabilitation; NA, not available; SpO2, oxygen saturation; VCO2, carbon dioxide production; VE, minute ventilation; VO2, oxygen uptake; WHO-FC, WHO functional class; WR, work load.