Intensity and daily reliability of the six-minute walk test in moderate chronic heart failure patients.
OBJECTIVE
To assess the intensity and daily reliability of the six-minute walk test (6MWT) in patients with moderate chronic heart failure (CHF).


METHODS
Evaluation of testing protocol.


METHODS
Hospitalized care.


METHODS
CHF patients under optimal drug treatment (CHF-D, n=12) or optimal drug treatment plus multisite cardiac pacing (CHF-P, n=12).


METHODS
Not applicable.


METHODS
Peak values of oxygen uptake (VO2) and heart rate during a symptom-limited, treadmill exercise test and VO2, heart rate, and distance during 2 6MWT sessions (morning and afternoon). The 6MWT intensity was estimated by the ratio (%) of VO2 and heart rate values measured at the end of this test in relation to the respective peak values obtained during the treadmill exercise test.


RESULTS
Subjects' VO2 and heart rate during the 6MWT were lower (P<.001) and were about 90% of the peak values (VO2: CHF-D, 90.5%+/-11.1%; CHF-P, 93.0%+/-13.2%; heart rate: CHF-D, 90.6%+/-6.6%; CHF-P, 91.4%+/-9.6%). The distance walked during both 6MWT sessions did not differ significantly, with low coefficients of variation (< or =2.0%) and high intraclass correlation coefficients (> or =.98). In CHF-D only, the patients' VO2 and heart rate were significantly (P<.01, P<.05, respectively) higher during the afternoon session.


CONCLUSIONS
Despite an intensity significantly lower but close to that of the symptom-limited exercise test, the 6MWT was well tolerated in both CHF groups. In these populations, the 6MWT is reliable on a daily basis, for the distance walked. However, for assessing VO2 and heart rate values in CHF-D patients, the 6MWT must always be performed at the same time of day.
Kervio
Gaëlle
G
Groupe de Recherche Cardio-Vasculaire, Université de Rennes 1, France. gaelle.kervio@club-internet.fr
Ville
Nathalie S
NS
Leclercq
Christophe
C
Daubert
Jean-Claude
JC
Carré
François
F
D000368:Aged; D001794:Blood Pressure; D015992:Body Mass Index; D001944:Breath Tests / Q000295:instrumentation / Q000379:methods*; D002908:Chronic Disease; D002985:Clinical Protocols / Q000592:standards; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012720:Severity of Illness Index; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D016138:Walking