TY - JOUR
T1 - Unreliability of the %VO2 reserve versus %heart rate reserve relationship for aerobic effort relative intensity assessment in chronic heart failure patients on or off beta-blocking therapy
AU - Mezzani, Alessandro
AU - Corrà, Ugo
AU - Giordano, Andrea
AU - Cafagna, Michele
AU - Adriano, Edvige Palazzo
AU - Giannuzzi, Pantaleo
PY - 2007/2
Y1 - 2007/2
N2 - BACKGROUND: Percentage of heart rate reserve (%HRR) has been shown to be equivalent to percentage of VO2 reserve (%VO2R) in normal individuals, but it is not clear whether this is also true for chronic heart failure (CHF) patients. DESIGN: This study aimed to evaluate the reliability of the %VO2R versus %HRR relationship for aerobic effort relative intensity assessment in CHF patients. METHODS: We studied 388 patients with CHF, of whom 213 were on carvedilol (CHF on βb) and 175 were off the drug (CHF off βb), and 40 normal individuals (N). %VO2R and %HRR values were evaluated at matched steps during cardiopulmonary exercise testing. The %VO2R versus %HRR regression was determined for each group (CHF, CHF on βb, CHF off βb, N) as a whole and as the mean of individual regressions. RESULTS: %VO2R strongly correlated with %HRR in both N and CHF, at both group and mean individual regressions, with slope and y-intercept values significantly lower and higher, respectively, in CHF than N. The 95% prediction interval of %VO2R for a given %HRR value was 24% points in N but rose to 41 in CHF, and the mean regression line coincided with identity line in N but not in CHF. These results were independent of beta-blockade. CONCLUSIONS: In CHF patients the %VO2R versus %HRR relationship is unreliable for assessment of aerobic effort relative intensity, because of a large prediction interval of %VO2R and lack of coincidence with the identity line, independently of beta-blocking therapy. This implies that the %VO2R versus %HRR relationship should be determined directly in each patient.
AB - BACKGROUND: Percentage of heart rate reserve (%HRR) has been shown to be equivalent to percentage of VO2 reserve (%VO2R) in normal individuals, but it is not clear whether this is also true for chronic heart failure (CHF) patients. DESIGN: This study aimed to evaluate the reliability of the %VO2R versus %HRR relationship for aerobic effort relative intensity assessment in CHF patients. METHODS: We studied 388 patients with CHF, of whom 213 were on carvedilol (CHF on βb) and 175 were off the drug (CHF off βb), and 40 normal individuals (N). %VO2R and %HRR values were evaluated at matched steps during cardiopulmonary exercise testing. The %VO2R versus %HRR regression was determined for each group (CHF, CHF on βb, CHF off βb, N) as a whole and as the mean of individual regressions. RESULTS: %VO2R strongly correlated with %HRR in both N and CHF, at both group and mean individual regressions, with slope and y-intercept values significantly lower and higher, respectively, in CHF than N. The 95% prediction interval of %VO2R for a given %HRR value was 24% points in N but rose to 41 in CHF, and the mean regression line coincided with identity line in N but not in CHF. These results were independent of beta-blockade. CONCLUSIONS: In CHF patients the %VO2R versus %HRR relationship is unreliable for assessment of aerobic effort relative intensity, because of a large prediction interval of %VO2R and lack of coincidence with the identity line, independently of beta-blocking therapy. This implies that the %VO2R versus %HRR relationship should be determined directly in each patient.
KW - Beta-blockers
KW - Chronic heart failure
KW - Heart rate reserve
KW - Relative effort intensity
KW - V reserve
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U2 - 10.1097/HJR.0b013e328011649b
DO - 10.1097/HJR.0b013e328011649b
M3 - Article
C2 - 17301633
AN - SCOPUS:33847053922
VL - 14
SP - 92
EP - 98
JO - European Journal of Cardiovascular Prevention and Rehabilitation
JF - European Journal of Cardiovascular Prevention and Rehabilitation
SN - 1741-8267
IS - 1
ER -