BACKGROUND: The six-minute walk test (6-MWT) is widely used to assess exercise tolerance in chronic heart failure patients (CHF). The aim of this study was to analyse cardiorespiratory parameters kinetics during the 6-MWT in CHF and in healthy subjects. METHODS: A treadmill, symptom-limited exercise test and a 6-MWT were performed by 14 CHF under optimal drug treatment (CHFD), 17 CHF with cardiac resynchronization (CHFP), and 12 healthy subjects. Cardiorespiratory responses were assessed by a validated portable system. RESULTS: All subjects exceeded their ventilatory threshold during the 6-MWT. Healthy subjects and CHF performed the 6-MWT around 75 and 90% of peak oxygen uptake (V'O2) respectively (P<0.001). In CHF, a steady state was observed only for walking speed and V'O2, with a slight delay in comparison with healthy subjects, for whom a steady state was also observed for carbon dioxide production and ventilation (V'E). During the 6-MWT, the V'E adaptation was due mainly to an increase in tidal volume (VT) in CHFD, whereas in CHFP, it was due to a similar increase in VT and breathing frequency (f). In these patients, the 6-MWT VT/f slope was lower than in CHFD (P<0.01). CONCLUSIONS: During the 6-MWT, the V'O2 steady state is slightly delayed in CHF, which could be related partly to their higher exercise intensity. Moreover, each CHF group is characterized by a specific ventilation components response during the 6-MWT.
BACKGROUND: The six-minute walk test (6-MWT) is widely used to assess exercise tolerance in chronic heart failurepatients (CHF). The aim of this study was to analyse cardiorespiratory parameters kinetics during the 6-MWT in CHF and in healthy subjects. METHODS: A treadmill, symptom-limited exercise test and a 6-MWT were performed by 14 CHF under optimal drug treatment (CHFD), 17 CHF with cardiac resynchronization (CHFP), and 12 healthy subjects. Cardiorespiratory responses were assessed by a validated portable system. RESULTS: All subjects exceeded their ventilatory threshold during the 6-MWT. Healthy subjects and CHF performed the 6-MWT around 75 and 90% of peak oxygen uptake (V'O2) respectively (P<0.001). In CHF, a steady state was observed only for walking speed and V'O2, with a slight delay in comparison with healthy subjects, for whom a steady state was also observed for carbon dioxide production and ventilation (V'E). During the 6-MWT, the V'E adaptation was due mainly to an increase in tidal volume (VT) in CHFD, whereas in CHFP, it was due to a similar increase in VT and breathing frequency (f). In these patients, the 6-MWT VT/f slope was lower than in CHFD (P<0.01). CONCLUSIONS: During the 6-MWT, the V'O2 steady state is slightly delayed in CHF, which could be related partly to their higher exercise intensity. Moreover, each CHF group is characterized by a specific ventilation components response during the 6-MWT.
Authors: Melissa Jehn; Martin Halle; Tibor Schuster; Henner Hanssen; Michael Weis; Friedrich Koehler; Arno Schmidt-Trucksäss Journal: Eur J Appl Physiol Date: 2009-07-18 Impact factor: 3.078
Authors: Mayron F Oliveira; Gabriela Zanussi; Bianca Sprovieri; Denise M L Lobo; Luiz E Mastrocolla; Iracema I K Umeda; Priscila A Sperandio Journal: Arq Bras Cardiol Date: 2016-01-22 Impact factor: 2.000