Open AccessLactate threshold is not an onset of insufficient oxygen supply to the working muscle in patients with chronic heart failure
Author(s) -
Yamabe Hiroshi,
Itoh Kazushi,
Yasaka Yoshinori,
Takata Teruo,
Yokoyama Mitsuhiro
Publication year - 1994
Publication title -
clinical cardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.263
H-Index - 72
eISSN - 1932-8737
pISSN - 0160-9289
DOI - 10.1002/clc.4960170709
Subject(s) - medicine , cardiology , heart failure , heart rate , work rate , circulatory system , oxygen , blood lactate , oxygen delivery , anesthesia , blood pressure , chemistry , organic chemistry
Abstract It has been argued that the lactate threshold (LT) serves as an index to reflect circulatory insufficiency in transporting oxygen during submaximal exercise in patients with chronic heart failure (CHF). We examined whether or not the LT was related to an insufficient oxygen supply in patients with CHF. Sixty‐nine patients were divided by NYHA classification. All underwent invasive cardiopulmonary exercise testing. The rate of increase in oxygen delivery (O 2 D) versus VO 2 (ΔO 2 D/ ΔVO 2 ) was significantly lowered when work rate exceeded LT, that is, 1.32 ± 0.35 to 1.05 ± 0.37 (p < 0.01), 1.22 ± 0.40 to 0.98 ± 0.40 (p < 0.05), and 1.04 ± 0.26 to 0.78 ± 0.39 (p < 0.05) in NYHA classes I, II, and III, respectively. However, the rate of increase in leg O 2 D versus leg VO 2 (ΔLO 2 D/ΔLVO 2 ) did not change, that is, 1.25 ± 0.20 to 1.29 ± 0.20 (NS), 1.27 ± 0.23 to 1.21 ± 0.28 (NS), and 1.19 ± 0.24 to 1.15 ± 0.17 (NS) in classes I, II, and III, respectively. Leg venous PO 2 was significantly different among three groups, that is, 23.7 ± 3.4 mmHg, 23.2 ± 2.8 mmHg, and 20.1 ± 2.3 mmHg (p < 0.001), respectively. Thus, the oxygen supply to the working muscle did not become insufficient when work rate exceeded LT, and the LT occurred at different levels of leg PO 2 . It was concluded that the LT was not a result of anaerobiosis in patients with CHF.