title: Relationship of resting B-type natriuretic peptide level to cardiac work and total physical work capacity in heart failure patients.
abstract: OBJECTIVE
  Plasma B-type natriuretic peptide (BNP) levels obtained at rest have been previously shown to be correlated with the global functional capacity measures of peak oxygen uptake (V(O(2peak))) and the minute ventilation/carbon dioxide (VE/V(O(2))) slope. The purpose of this study was to assess the relationship of the plasma BNP level to the rate-pressure product (RPP) as an indicator of central or cardiac work capacity.
  
  
  METHODS
  Twenty-two subjects (12 men), mean age 57 +/- 12 years, diagnosed with heart failure (8 ischemic/14 nonischemic) were recruited. All subjects were stable on optimal medical therapy for at least 1 month. Blood samples for BNP level analysis were obtained at rest. Subjects underwent a symptom-limited treadmill exercise test using a ramping protocol while V(O(2)), heart rate (HR), and blood pressure (BP) were monitored. Correlation analyses were conducted to assess the relationship of BNP level to RPP level, V(O(2peak), VE/V(O(2)) slope, end-tidal CO(2) pressure (P(ET)CO(2)), and left ventricular ejection fraction (LVEF).
  
  
  RESULTS
  Resting BNP levels were significantly correlated with RPP levels (r = -0.69). The BNP level and the RPP level were correlated with V(O(2peak)) (r = -0.63 and r = 0.66, respectively) and VE/V(O(2)) slope (r = 0.53 and r = -0.54, respectively). The RPP level but not the BNP level was correlated with P(ET)CO(2) (r = 0.57). Neither BNP nor RPP levels were well correlated with LVEF (r = -0.26 and r = 0.14, respectively).
  
  
  CONCLUSIONS
  The results of this study suggest that resting plasma BNP level may be a useful clinical measure for evaluating both global functional capacity and myocardial specific work capacity in individuals with heart failure.
authors: Division of Physical Therapy Education, University of Nebraska Medical Center, 984420 Nebraska Medical Center, Omaha, Nebraska 68198, USA. jfnorman@unmc.edu
authors: Joseph F
authors: JF
authors: Norman
authors: Bunny J
authors: BJ
authors: Pozehl
authors: Kathleen A
authors: KA
authors: Duncan
authors: Melody A
authors: MA
authors: Hertzog
authors: Ahmed S
authors: AS
authors: Elokda
authors: Steven K
authors: SK
authors: Krueger
mesh_terms: D018450:Disease Progression; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D015200:Fluoroimmunoassay; D005500:Follow-Up Studies; D006333:Heart Failure / Q000097:blood* / Q000503:physiopathology / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011379:Prognosis; D012146:Rest / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D020097:Natriuretic Peptide, Brain