In:
American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Vol. 300, No. 4 ( 2011-04), p. H1545-H1555
Abstract:
This investigation elucidated the underlying mechanisms of functional impairments in patients with heart failure (HF) by simultaneously comparing cardiac-cerebral-muscle hemodynamic and ventilatory responses to exercise among HF patients with various functional capacities. One hundred one patients with HF [New York Heart Association HF functional class II (HF-II, n = 53) and functional class III (HF-III, n = 48) patients] and 71 normal subjects [older control (O-C, n = 39) and younger control (Y-C, n = 32) adults] performed an incremental exercise test using a bicycle ergometer. A recently developed noninvasive bioreactance device was adopted to measure cardiac hemodynamics, and near-infrared spectroscopy was employed to assess perfusions in the frontal cerebral lobe (Δ[THb] FC ) and vastus lateralis muscle (Δ[THb] VL ). The results demonstrated that the Y-C group had higher levels of cardiac output, Δ[THb] FC , and Δ[THb] VL during exercise than the O-C group. Moreover, these cardiac/peripheral hemodynamic responses to exercise in HF-III group were smaller than those in both HF-II and O-C groups. Although the change of cardiac output caused by exercise was normalized, the amounts of blood distributed to frontal cerebral lobe and vastus lateralis muscle in the HF-III group significantly declined during exercise. The HF-III patients had lower oxygen-uptake efficiency slopes (OUES) and greater V̇e-V̇o 2 slopes than the HF-II patients and age-matched controls. However, neither hemodynamic nor ventilatory response to exercise differed significantly between the HF-II and O-C groups. Cardiac output, Δ[THb] FC , and Δ[THb] VL during exercise were directly related to the OUES and V̇o 2peak and inversely related to the V̇e-V̇co 2 slope. Moreover, cardiac output or Δ[THb] FC was an effect modifier, which modulated the correlation status between Δ[THb] VL and V̇e-V̇co 2 slope. We concluded that the suppression of cerebral/muscle hemodynamics during exercise is associated with ventilatory abnormality, which reduces functional capacity in patients with HF.
Type of Medium:
Online Resource
ISSN:
0363-6135
,
1522-1539
DOI:
10.1152/ajpheart.00867.2010
Language:
English
Publisher:
American Physiological Society
Publication Date:
2011
detail.hit.zdb_id:
603838-4
detail.hit.zdb_id:
1477308-9
SSG:
12
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