Oxygen consumption during corridor walk testing in chronic cardiac failure

European Heart Journal (1992) 13, 789-793 Oxygen consumption during corridor walk testing in chronic cardiac failure M. RILEY, J. MCPARLAND, C. F. ST...
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European Heart Journal (1992) 13, 789-793

Oxygen consumption during corridor walk testing in chronic cardiac failure M. RILEY, J. MCPARLAND, C. F. STANFORD AND D. P. NICHOLLS

Royal Victoria Hospital, Belfast, N. Ireland KEY WORDS: Exercise testing, heart failure, corridor walk test. We have examined the use of a 6-min corridor walk test in the assessment of functional capacity in 16 patients with chronic cardiac failure. VO2 was determined concurrently by a portable 'Oxylog'. Three tests were performed sequentially, and although there was a significant increase in distance walked and highest VO2 achieved between the first and second tests, good reproducibility was attained between the second and third tests. Both walk test variables correlated well with previously determined peak achieved VO2, and NYHA classes were separated adequately. Corridor walk testing, with or without measurement of VO2 should be a useful adjunct to maximal exercise testing in interventional studies.

Introduction Functional capacity in patients with chronic cardiac failure (CCF) has traditionally been measured in terms of New York Heart Association grade1'1, but as this approach is subjective and only semi-quantitative, exercise testing to the patient's symptom-limited maximum has become popular1231. This provides objective, quantitative data, the most frequent parameters quoted being exercise time and maximal or peak achieved oxygen uptake (PVO2). Maximal exercise testing has the disadvantage that it may be unpleasant for patients and, particularly if oxygen consumption (VO2) is to be measured, requires experienced personnel and the use of expensive equipment. Distance walked during a 6-min corridor walk test has been proposed as a simple means whereby functional capacity may be assessed, and has the added advantage of reproducing more closely and naturally the daily activity of the subjects. It was first used in patients with pulmonary disease1451, but more recently has been applied to patients with heart failure161. A fair correlation between distance walked and PVO2 measured during maximal treadmill testing was achieved in this latter study and NYHA functional grades were able to be separated adequately. During treadmill testing, oxygen uptake is more reproducible than treadmill time1781 and we hypothesized that the concurrent measurement of VO2 during a corridor walk test might add further information for the assessment of functional capacity. In addition, it should provide a means of determining the normal maximum effort made by patients during their everyday activity. Such assessment may be more relevant from the patients' point of view, as improvements in PVO2 may not necessarily improve the quality of life, this being a major goal of therapeutic intervention in CCF.

Submitlcd for publication on 12 Apnl 1991, and in revised form 16 October 1991 Correspondence. Dr Nicholls, Royal Victoria Hospital, Belfast, Northern Ireland. 0I95-668X/92/O6O789 + 05 $03 00/0


Fourteen men and two women (mean age 65-2 years, range 48-76) with CCF took part in the study. All had been clinically stable and drug therapy had remained unaltered for a minimum of 2 months prior to the study. Seven patients were in NYHA functional class II, seven in class III and two in class IV. The mean left ventricular ejection fraction as determined by radionuclide angiography was 0-26 (range 009-0-43; normal > 0-50) and the cardio-thoracic ratio >0-50 in all subjects. All were taking loop diuretics with a median dose of frusemide or equivalent of 80 mg (range 40-240 mg). In addition, two patients were taking captopril and three flosequinan, a new vasodilator drug (Boots, U.K.). PROTOCOL

After at least one familiarization test, subjects performed a symptom-limited maximal treadmill test with on-line respired gas analysis for determination of PVO,. The method of gas analysis was as described previously^1. Following this, on three separate occasions at weekly intervals, a self-paced 6-min corridor walk test with simultaneous measurement of VO2 was carried out. Subjects were asked to walk back and forth along a 25 m long corridor for 6 min with the aim of going as far as possible. They were permitted to vary their pace or even to stop for a period if necessary. The total distance covered in the 6 min was noted and the subject's VO2 recorded every minute. MEASUREMENT OF VO 2

VO2 was measured with an Oxylog (P.K. Morgan, U.K.), a portable instrument weighing 2-61 kg and representing typically

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