Article

The oxygen uptake efficiency slope (OUES) is an exercise parameter
with strong prognostic value in the heart failure population. Yet, the optimal
determination method of OUES remains unclear. The purpose of the present study
was to investigate the influence of the ventilatory anaerobic threshold (VAT) and
occurrence of a plateau in oxygen uptake (VO2) on determination of OUES from
submaximal exercise data in patients with chronic heart failure (CHF). METHODS
AND RESULTS: Ninety-eight CHF patients (New York Heart Association class II-III)
were included. All patients performed a symptom-limited exercise test with gas
exchange analysis on a cycle ergometer. VAT was determined by the V-slope method
and OUES was derived via least-squares linear regression using 100% (OUES100),
90% (OUES90), and 75% (OUES75) of exercise duration, and, in addition, by using
only the first 50% of data points preceding VAT (OUES(1/2)VAT), all data
preceding VAT (OUESVAT), and only data following VAT (OUESpostVAT). Whereas
OUESVAT (1720 +/- 430 ml/min/log(l/min)), OUES75 (1811 +/- 476
ml/min/log(l/min)), and OUESpostVAT (1742 +/- 564 ml/min/log(l/min)) were not
significantly different from OUES100 (1767 +/- 542 ml/min/log(l/min)),
OUES(1/2)VAT (1500 +/- 314 ml/min/log(l/min)) was significantly lower than all
other values (p < 0.01). When a VO2 plateau was present, OUES100 was lower than
OUES90 (p < 0.05). CONCLUSIONS: The study results indicate that OUES values
should be interpreted with caution when CHF patients do not reach the ventilatory
anaerobic threshold or when a VO2 plateau is present.

Langue : ANGLAIS