Accelerometer-based quantification of 6-minute walk test performance in patients with chronic heart failure: applicability in telemedicine.
BACKGROUND
Distance walked in the 6-minute walk test (6MWT) is an important prognostic parameter used clinically to assess functional status in patients with chronic heart failure (CHF). In this study, we investigated if alternative performance parameters with similar prognostic value can be gained from accelerometers.


RESULTS
Fifty CHF patients (age, 60.9 +/- 14.0 years) were asked to perform a 6MWT while wearing 2 accelerometers and 1 pedometer. Total 6MWT step frequency (SF) and activity counts (VMU) were correlated to 6MWT distance. The accelerometer was highly accurate at quantifying SF (detected vs. observed: r = 0.99; P < .001), whereas the pedometer was unreliable below 50 m/min. VMU increased linearly with walking speed (r = 0.99), and both SF and VMU correlated strongly with 6MWT distance (VMU: r = 0.91; SF: r = 0.87, respectively; P < .001) and each other (r = 0.80, P < .001).


CONCLUSIONS
Accelerometers are reliable in measuring physical performance during the 6MWT in CHF patients. Besides the simple acquisition of 6MWT distance currently used for patient assessment, accelerometers provide new data that might be useful to evaluate exercise performance during the 6MWT. This allows for routine assessment of exercise capacity in a home-based setting in the context of telemedicine.
Jehn
Melissa
M
Department of Prevention, Rehabilitation and Sports Medicine and Institute for Medical Statistics, Munich, Germany. jehn@sport.med.tum.de
Schmidt-Trucksäess
Arno
A
Schuster
Tibor
T
Hanssen
Henner
H
Weis
Michael
M
Halle
Martin
M
Koehler
Friedrich
F
D000328:Adult; D000368:Aged; D005080:Exercise Test / Q000295:instrumentation* / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017216:Telemedicine / Q000295:instrumentation* / Q000379:methods; D013997:Time Factors; D016138:Walking / Q000502:physiology*