Table 2

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
Baseline12 weeksWithin-group
p value
Baseline12 weeksWithin-group
p value
Peak respiratory exchange ratio1.25±0.101.23±±0.111.31±0.100.570.10
Peak WR (W)81±1982±230.4985±2397±27<0.01<0.01
Peak VO2 (mL/min/kg)17.8±2.618.1±3.40.4517.4±2.619.1±3.5<0.01<0.01
Peak VO2% predicted (%)69.7±12.370.9±13.50.4170.7±9.478.2±12.8<0.01<0.01
VO2 at AT (mL/min/kg)*10.8±1.611.4±2.70.1210.2±1.610.8±
VO2 at AT % predicted (%)*61.6±10.465.6±15.30.0961.7±10.665.6±
Resting heart rate (beats/min)80±1480±160.7975±1275±110.710.45
Peak heart rate (beats/min)141±25141±260.66145±15147±150.310.73
Δ VO2/Δ WR (mL/min/W)8.2±1.38.0±1.50.477.6±1.47.6±1.90.880.75
Oxygen pulse (mL/min/beat)6.9±1.77.0±1.70.396.6±1.57.3±1.7<0.010.01
VE-VCO2 slope37.6±6.836.6±6.50.3342.1±10.239.7±
Lowest SpO2 (%)90.2±4.791.3±3.90.0989.0±5.189.2±4.80.800.21
Muscle strength
Forearm (kg)NANANA28 (23–37)27 (25–37)0.74#NA
Quadriceps (kg)NANANA26.4±8.129.1±8.1<0.01NA
Other clinical parametersn=24n=24n=17n=17
WHO-FC (I/II/III/IV, mean)1/21/2/0, 2.04/19/1/0, 1.90.05#0/14/3/0, 2.24/12/1/0, 1.80.01#0.28##
6-min walk distance (m)468±102476±970.43498±96510±980.100.53
  • 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.