HEMODYNAMIC PROFILE OF SUBMAXIMAL CONSTANT WORKLOAD EXERCISE IN PATIENTS WITH HEART-FAILURE SECONDARY TO ISCHEMIC OR IDIOPATHIC DILATED CARDIOMYOPATHY

Constant workload exercise on an upright bicycle at submaximal levels of exercise intensity is frequently used in physical training programs . Nevertheless, only a few data are currently available on the hemodyn amic changes induced by constant workload exercise in patients with he art failure. The aim of this study was to assess the hemodynamic respo nse during submaximal constant-workload exercise at 2 different work r ates in patients with heart failure. The hemodynamic profile was asses sed by means of right-sided cardiac catheterization in 21 men with mod erate heart failure during submaximal-constant workload exercise perfo rmed an upright bicycle for 15 minutes. The intensity of constant work rate exercise was selected during a previous symptom-limited or maxim al test. The first submaximal test was performed at the level of the a naerobic threshold workload, corresponding to 64% of peak work rare, a nd the other test at 70% of anaerobic threshold workload (42% of peak work rate). During both submaximal tests, a marked increase in right h eart pressure was observed as compared with baseline. The increase in systolic pulmonary artery pressure was statistically not different bet ween the 2 tests (from 40 +/- 18 to 66 +/- 20 mm Hg during exercise at the anaerobic threshold workload, and from 39 +/- 16 to 63 +/- 21 mm Hg during exercise under anaerobic threshold). The increase in pulmona ry arterial wedge pressure was similar (from 20 +/- 10 to 35 +/- 13 mm Hg during exercise at the anaerobic threshold, and from 19 +/- 9 to 3 2 +/- 12 mm Hg during the other test). Cardiac output and heart rate w ere significantly higher during submaximal exercise at a higher worklo ad, paralleling the behavior of oxygen uptake. Finally, the hemodynami c profile during submaximal exercise at the anaerobic threshold worklo ad was quite similar to that observed during symptom-limited exercise. Thus, in patients with heart failure, submaximal exercise performed a t a constant workload, even at low exercise intensity, may determine r elevant pressure changes in pulmonary circulation. (C) 1998 by Excerpt a Medica, Inc.