title: Oxygen uptake efficiency slope in patients with chronic heart failure and coexisting respiratory disease.
abstract: BACKGROUND
  Oxygen uptake efficiency slope (OUES) is proposed as an objective index of cardiorespiratory functional reserve. The AIM of the present study was to evaluate the effect of coexisting respiratory diseases on OUES in patients with chronic heart failure (CHF) (New York Heart Association class II-III) during incremental exercise testing.
  
  
  METHODS
  Fifty-five males were allocated to three groups: group 1-19 patients with only CHF (CHF); group 2-17 patients with CHF and a history of respiratory disease (CHF-RD); group 3-19 matched controls (C). They all underwent comprehensive lung function testing and symptom-limited ramp cardiopulmonary exercise test on a cycle ergometer.
  
  
  RESULTS
  The patients with a history of respiratory diseases had the lowest value of OUES, but their results were not significantly different from those of the CHF patients (OUES mL.min(-1).logL(-1)= 1461 +/- 268 vs. 1571 +/- 383 vs. 2112 +/- 263 in controls). Significant correlation was found between OUES and important functional variables: VO2peak (r=0.833), V(E)/NCO2 slope (r = -0.757), FEV1 (r=0.582), T(L,CO) (r=0.574), and EF% (r=0.350).
  
  
  CONCLUSIONS
  OUES is significantly reduced in patients with CHF and tends to be lower in the presence of a respiratory disease. It can be regarded as an useful, reliable physiologic marker of reduced ventilatory efficiency and cardiorespiratory reserve in chronic heart failure.
authors.affiliation: Department of Pathophysiology, Clinic of Cardiology, St. George University Hospital, Medical University, Plovdiv, Bulgaria.
authors.forename: Blagoy I
authors.initials: BI
authors.lastname: Marinov
authors.forename: Maria P
authors.initials: MP
authors.lastname: Tokmakova
authors.forename: Stefan S
authors.initials: SS
authors.lastname: Kostianev
authors.forename: Atanas B
authors.initials: AB
authors.lastname: Djurdjev
mesh_terms: D005080:Exercise Test; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012120:Respiration Disorders / Q000150:complications*; D012129:Respiratory Function Tests