Predicting peak oxygen consumption during a conservative ramping protocol: implications for the heart failure population.
OBJECTIVE
A significant discrepancy between measured oxygen consumption (VO(2)) (via ventilatory expired gas analysis) and estimated VO(2) (via the imposed workload) frequently is reported in the heart failure (HF) population during symptom-limited exercise testing. The purpose of this investigation was to examine the difference between measured and estimated VO(2) (VO(2) discrepancy) during a highly conservative ramping protocol.


METHODS
For this study, 28 subjects with compensated HF (20 men and 8 women; age, 51.1 +/- 14.6 years) and 19 healthy control subjects (age-, gender-, and activity-matched to an HF subgroup) underwent symptom-limited exercise testing (treadmill) with ventilatory expired gas analysis.


RESULTS
Peak estimated and measured VO(2) values were significantly higher in the age-, gender-, and activity-matched control group than in the HF group, but the change in measured VO(2) per change in estimated VO(2) (Deltameasured/Deltaestimated VO(2) slope) and the VO(2) discrepancy did not reach statistical significance. Peak estimated VO(2) was a significant predictor of peak measured VO(2) in the overall HF group (R2 = 0.90; P <.001).


CONCLUSIONS
Although estimated VO(2) is not considered a replacement for measured VO(2), these results indicate that a highly conservative exercise protocol may allow for a more accurate prediction of peak measured VO(2) via the estimated oxygen cost for a given workload in patients with compensated HF.
Arena
Ross
R
Department of Physical Therapy, Box 980224, Virginia Commonwealth University/MCV Campus, Richmond, VA 23298-0224, USA. rarena@vcu.org
Humphrey
Reed
R
Peberdy
Mary Ann
MA
Madigan
Michael
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002985:Clinical Protocols; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012044:Regression Analysis