Relationship of Resting B-type Natriuretic Peptide Level to Cardiac Work and Total Physical Work Capacity in Heart Failure Patients.

J Cardiopulm Rehabil Prev. 2009 Jun 24; Norman JF, Pozehl BJ, Duncan KA, Hertzog MA, Elokda AS, Krueger SKPURPOSE: 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 (&OV0312;O2peak) and the minute ventilation/carbon dioxide (VE/&OV0312;co2) 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 &OV0312;O2, heart rate (HR), and blood pressure (BP) were monitored. Correlation analyses were conducted to assess the relationship of BNP level to RPP level, &OV0312;O2peak, VE/&OV0312;CO2 slope, end-tidal CO2 pressure (PETCO2), 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 &OV0312;O2peak (r = -0.63 and r = 0.66, respectively) and VE/&OV0312;CO2 slope (r = 0.53 and r = -0.54, respectively). The RPP level but not the BNP level was correlated with PETCO2 (r = 0.57). Neither BNP nor RPP levels were well correlated with LVEF (r = -0.26 and r = 0.14, respectively). DISCUSSION: 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.