Article

Cardiopulmonary exercise testing is widely used in clinical assessment
and exercise prescription. However, significant differences in physiological
responses can occur depending on testing protocol. The aim of this study was to
evaluate the cardiopulmonary responses to different incremental cycle pedaling
cadences in cardiac patients. METHODS: Eleven men with coronary artery disease
(CAD) and 12 men with chronic heart failure (CHF) performed 2 maximal cycle tests
at constant cadence (60-70 rpm, at fixed cadence) and at progressive cadence.
Peak values for oxygen uptake (V(O(2)peak)), workload (W(peak)), and heart rate
(HR(peak)); ventilatory threshold (VT); and the oxygen uptake (VO2) per unit work
rate (WR) increment (DeltaV(O(2))/DeltaWR) obtained using 2 protocols were
determined. RESULTS: V(O(2)peak) and W(peak), respectively, were higher during
increasing cadence (INCR) compared with fixed cadence (FIX) protocol both in
patients with CAD (32.7 +/- 5.4 vs 28.1 +/- 7.0 mL . kg(-1) . min(-1), P = .01;
214 +/- 42 vs 150 +/- 28 W, P = .001) and in patients with CHF (20.3 +/- 7.4 vs
17.2 +/- 5.5 mL . kg(-1) . min(-1), P = .006; 133 +/- 45 vs 104 +/- 33 W, P =
.005). No differences were seen in HR(peak). Both in patients with CAD and in
patients with CHF, V(O(2)) (21.7 +/- 5.5 vs 16.8 +/- 5.3 and 12.3 +/- 7.4 vs 9.3
+/- 2.8 mL . kg(-1) . min(-1)) and HR (114 +/- 14 vs 98 +/- 13 and 92 +/- 17 vs
80 +/- 17 bpm) at VT were significantly higher in INCR than in FIX protocol. No
differences were seen in workload at VT. DeltaV(O(2))/DeltaWR during INCR
protocol were higher in patients with CAD (13.4 +/- 1.8 vs 9.5 +/- 2.6 mL .
kg(-1) . W(-1), P = .006) and patients with CHF (13.6 +/- 4.1 vs 8.7 +/- 1.9 mL .
kg(-1) . W(-1), P = .006). DISCUSSION: These findings indicate that in tests at
fixed cadence, there occurs an earlier activation of the anaerobic mechanisms
leading to a premature exhaustion before a cardiopulmonary endpoint has been
achieved.

Langue : ANGLAIS

Tiré à part : OUI