title: Usefulness of anaerobic threshold to peak oxygen uptake ratio to determine the severity and pathophysiological condition of chronic heart failure.
abstract: Anaerobic threshold (AT) and peak oxygen uptake (V˙O2) are well known as indicators of severity and prognosis of heart failure. Since these parameters are regulated by many factors, multiple organ dysfunction may occur in chronic heart failure, and these two parameters would vary among patients. However, it is not clear whether AT and peak V˙O2deteriorate similarly. Therefore, we planned to compare the degree of deterioration of these two parameters using a ratio of AT and peak V˙O2(%AT/peak), and evaluated its significance in heart failure subjects.
  
  
  
  One hundred ninety-four stable heart failure patients who had optimal medical treatment for at least 3 months were enrolled. Cardiopulmonary exercise testing, echocardiography, and blood sampling were examined within one week. Since %AT/peak varied from 50.3% to 108.5%, we divided patients into tertiles of %AT/peak [Group A, 50.1-70.0 (n=112), Group B, 70.1-90.0 (n=64), Group C, 90.1-110.0 (n=18)], and compared factors relating with skeletal muscle and heart failure among these 3 groups.
  
  
  
  In Group A, ratio of measured AT against predicted value (%AT) and measured peak V˙O2against predicted value (%peak V˙O2) were similar (80.3±19.0% and 80.4±17.1%, respectively). Peak V˙O2became lower as %AT/peak increased (Group B; 65.6±14.8%, p<0.01 vs. Group A, Group C; 38.3±9.7%, p<0.01 vs. Group B). On the other hand, %AT in Group B (77.1±18.5%) was similar to Group A, and diminished in Group C (58.0±8.2%, p<0.05 vs. Group B). Peak work rate and lean body mass were smaller in Group B than those in Group A. Although, left ventricular ejection fraction and E/E' deteriorated in Group B compared with Group A, plasma B-type natriuretic peptide and estimated glomerular filtration rate stayed constant in Group B and deteriorated in Group C.
  
  
  
  %AT/peak showed negative correlation with peak V˙O2. In chronic heart failure, muscle weakness occurs at an early stage, and this can be evaluated using %AT/peak.
authors: Department of Medicine and Biological Science, Graduate School of Medicine, Gunma University School of Medicine, Gunma, Japan.
authors: Junichi
authors: J
authors: Tomono
authors: Gunma Prefectural Cardiovascular Center, Gunma, Japan. Electronic address: h-adachi@ops.dti.ne.jp.
authors: Hitoshi
authors: H
authors: Adachi
authors: Gunma Prefectural Cardiovascular Center, Gunma, Japan.
authors: Shigeru
authors: S
authors: Oshima
authors: Department of Medicine and Biological Science, Graduate School of Medicine, Gunma University School of Medicine, Gunma, Japan.
authors: Masahiko
authors: M
authors: Kurabayashi
mesh_terms: D000368:Aged; D015308:Anaerobic Threshold / Q000502:physiology*; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology*; D012720:Severity of Illness Index
chemical_list: D020097:Natriuretic Peptide, Brain
keywords: Anaerobic threshold/peak ratio; Cardiopulmonary exercise test; Heart failure; Muscle strength