Publikation
Oxygen uptake kinetics during low level exercise in patients with heart failure: relation to neurohormones, peak oxygen consumption, and clinical findings
Wissenschaftlicher Artikel/Review - 01.02.1999
Brunner-La Rocca H P, Weilenmann Daniel, Follath F, Schlumpf M, Rickli Hans, Schalcher C, Maly F E, Candinas R, Kiowski W
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OBJECTIVE: To investigate whether oxygen uptake (VO2) kinetics during low intensity exercise are related to clinical signs, symptoms, and neurohumoral activation independently of peak oxygen consumption in chronic heart failure. DESIGN: Comparison of VO2 kinetics with peak VO2, neurohormones, and clinical signs of chronic heart failure. SETTING: Tertiary care centre. PATIENTS: 48 patients with mild to moderate chronic heart failure. INTERVENTIONS: Treadmill exercise testing with "breath by breath" gas exchange monitoring. Measurement of atrial natriuretic factor (ANF), brain natriuretic peptide (BNP), and noradrenaline. Assessment of clinical findings by questionnaire. MAIN OUTCOME MEASURES: O2 kinetics were defined as O2 deficit (time [rest to steady state] x DeltaVO2 -sigmaVO2 [rest to steady state]; normalised to body weight) and mean response time of oxygen consumption (MRT; O2 deficit/DeltaVO2). RESULTS: VO2 kinetics were weakly to moderately correlated to the peak VO2 (O2 deficit, r = -0.37, p < 0.05; MRT, r = -0.49, p < 0.001). Natriuretic peptides were more closely correlated with MRT (ANF, r = 0.58; BNP, r = 0.53, p < 0.001) than with O2 deficit (ANF, r = 0.48, p = 0.001; BNP, r = 0.37, p < 0.01) or peak VO2 (ANF, r = -0.40; BNP, r = -0.31, p < 0.05). Noradrenaline was correlated with MRT (r = 0. 33, p < 0.05) and O2 deficit (r = 0.39, p < 0.01) but not with peak VO2 (r = -0.20, NS). Symptoms of chronic heart failure were correlated with all indices of oxygen consumption (MRT, r = 0.47, p < 0.01; O2 deficit, r = 0.39, p < 0.01; peak VO2, r = -0.48, p < 0. 01). Multivariate analysis showed that the correlation of VO2 kinetics with neurohormones and symptoms of chronic heart failure was independent of peak VO2 and other variables. CONCLUSIONS: Oxygen kinetics during low intensity exercise may provide additional information over peak VO2 in patients with chronic heart failure, given the better correlation with neurohormones which represent an index of homeostasis of the cardiovascular system.