Article

Measures of ventilatory inefficiency, such as the slope of the
relation between ventilation and carbon dioxide production ((Equation is included
in full-text article.)slope) and the oxygen uptake efficiency slope (OUES) have
recently been shown to be strong prognostic markers in patients with heart
failure. Little is known regarding the effects of exercise training on these
indices. METHODS: Fifty heart failure patients (mean age = 55 +/- 6 years,
ejection fraction = 33 +/- 6%) referred to a residential cardiac rehabilitation
program were randomized to a 2-month high-intensity training program (n = 24) or
to a control group (n = 26). Before and after the study period, maximal
cardiopulmonary exercise testing was performed, and markers of ventilatory
inefficiency were determined. RESULTS: Training increased peak oxygen uptake
((Equation is included in full-text article.); 23%), exercise time (29%), and
peak workload (28%), whereas no changes were observed in controls (all P < .05
between groups). No differences were observed in the (Equation is included in
full-text article.)slope in either group. However, the ventilatory equivalent for
oxygen ((Equation is included in full-text article.)ratio) was reduced at matched
work rates throughout exercise (P < .01). The OUES increased by 12% in the
exercise groups (P = .003) and 4% in controls. At baseline, trained patients had
an OUES that was 69% of the age-predicted value and this improved to 78% after
training (P = .004). The change in OUES was significantly related to the change
in peak (Equation is included in full-text article.)with training (r = 0.63, P =
.001). CONCLUSION: High-intensity training resulted in marked improvements in
exercise capacity in patients with heart failure. Training improved the OUES and
reduced the (Equation is included in full-text article.)ratio, but the (Equation
is included in full-text article.)slope was unchanged. Among measures of
ventilatory inefficiency, the OUES may be more sensitive to training than the
(Equation is included in full-text article.)slope.

Langue : ANGLAIS

Tiré à part : OUI