Reduced cardiopulmonary exercise capacity in patients with chronic heart failure: impact of left ventricular systolic dysfunction

Abstract

To evaluate the cardiopulmonary exercise capacity in patients with chronic heart failure (CHF). 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. (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)]. (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.