Objective: To evaluate the cardiopulmonary exercise capacity in patients with chronic heart failure (CHF).
Methods: Cardiopulmonary exercise testing on bicycle ergometer was performed in 74 age, gender and BMI-matched patients. There were 37 patients with LVEF < 0.45 in CHF group and another 37 patients with LVEF > 0.50 in control group. VO(2)AT, VO(2)Peak, Load AT, Load peak and VE/VCO(2) slope were measured and compared.
Results: (1) VO(2)AT, VO(2)Peak, Load AT and Load peak were all significantly reduced in patients with CHF as compared with controls [VO(2)AT: (11.3 +/- 2.3) ml x kg(-1) x min(-1) vs (12.8 +/- 2.5) ml x kg(-1) x min(-1), P < 0.05; VO(2)peak: (15.2 +/- 4.3) ml x kg(-1) x min(-1) vs (17.3 +/- 3.9) ml x kg(-1) x min(-1), P < 0.05; Load AT: (25.2 +/- 18.8) J x s(-1) vs (45.6 +/- 18.7) J x s(-1), P < 0.01; Load peak: (54.9 +/- 22.5) J x s(-1) vs (80.3 +/- 21.6) J x s(-1), P < 0.01]; (2) VE/VCO(2) slope increased in patients with CHF as compared with controls [(36.7 +/- 6.7) vs (30.3 +/- 4.3), P < 0.01]; (3) None of VO(2)AT, VO(2), Peak Load AT, Load peak or VE/VCO(2) slope was correlated with LVEF [(r = 0.054, P > 0.05); (r = 0.03, P > 0.05); (r = 0.310, P > 0.05); (r = 0.174, P > 0.05); (r = -0.203, P > 0.05)]; VO(2)AT, VO(2)Peak, Load AT and Load peak were all correlated negatively with a higher NYHA grade [(r = -0.477, P < 0.01); (r = -0.591, P < 0.01); (r = -0.640, P < 0.01); (r = -0.672, P < 0.01)]; VE/VCO(2) slope correlated positively with a higher NYHA grade (r = 0.652, P < 0.01); None of VO(2)AT, VO(2)Peak, Load AT, Load peak or VE/VCO(2) slope was correlated with LVMI [r = 0.045, P > 0.05); (r = -0.017, P > 0.05); (r = -0.214, P > 0.05); (r = -0.123, P > 0.05); (r = 0.106, P > 0.05)].
Conclusion: (1) Cardiopulmonary exercise capacity is reduced in CHF patients. (2) None of VO(2)AT, VO(2)Peak, Load AT, Load peak and VE/VCO(2) slope is correlated with LVEF; VO(2)AT, VO(2)Peak, Load AT and Load peak all correlate negatively with the higher NYHA grade; VE/VCO(2) slope correlates positively with a higher NYHA grade; None of VO(2)AT, VO(2)Peak, Load AT, Load peak or VE/VCO(2) slope correlates with LVMI. An analysis of gas metabolism is a safe, accurate and scientific testing method of exercise tolerance.