title: Suppression of cerebral hemodynamics is associated with reduced functional capacity in patients with heart failure.
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 Ve-Vo(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 Vo(2peak) and inversely related to the Ve-Vco(2) slope. Moreover, cardiac output or Δ[THb](FC) was an effect modifier, which modulated the correlation status between Δ[THb](VL) and Ve-Vco(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.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Gung Memorial Hospital, Keelung, Taiwan.
authors.forename: Tieh-Cheng
authors.initials: TC
authors.lastname: Fu
authors.forename: Chao-Hung
authors.initials: CH
authors.lastname: Wang
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Hsu
authors.forename: Wen-Jin
authors.initials: WJ
authors.lastname: Cherng
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Huang
authors.forename: Jong-Shyan
authors.initials: JS
authors.lastname: Wang
mesh_terms: D000368:Aged; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000502:physiology; D002540:Cerebral Cortex / Q000098:blood supply* / Q000503:physiopathology; D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen