Premium
Muscle Vasoconstriction During Chemoreceptors Stimulation in Patients with Heart Failure
Author(s) -
Negrao Carlos Eduardo,
Vanna Andrea,
Braga Ana,
Laterza Mateus,
Ueno Linda,
Barretto Antonio,
Middlekauff Holly,
Rondon Maria
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1268
Subject(s) - hypercapnia , medicine , vasodilation , anesthesia , hypoxia (environmental) , peripheral chemoreceptors , central chemoreceptors , forearm , vasoconstriction , cardiology , microneurography , hypoxic pulmonary vasoconstriction , plethysmograph , ventilation (architecture) , stimulation , heart rate , respiratory system , blood pressure , baroreflex , surgery , oxygen , chemistry , carotid body , mechanical engineering , organic chemistry , engineering
Objective: We tested the hypothesis that muscle vasodilatation during hypoxia and hypercapnia would be altered in patients with heart failure (HF). Methods: Sixteen HF patients (49±3 years, Class II‐III, NYHA) and 11 age‐paired normal controls were studied. Peripheral chemoreflex control was evaluated by inhalation of 10% O 2 and 90% N 2 and central chemoreflex control by inhalation of 7% CO 2 and 93% O 2 during 3 minutes. MSNA was evaluated by microneurography and forearm blood flow by venous occlusion plethysmography. Results: Baseline MSNA and pulmonary ventilation were significantly greater in patients with HF. Forearm vascular conductance (FVC) was not different between the groups. During hypoxia and hypercapnia, MSNA responses were significantly greater in patients with HF than in normal controls. FVC responses were significantly lower in HF patients (Hypoxia: 0.00±0.10 vs. 0.76±0.25 U, P=0.001; Hypercapnia: −0.29±0.10 vs. 0.37±0.18 U, P=0.001). There was a significant correlation between peak of response in MSNA and forearm blood flow (Hypoxia: r=0.40, P<0.05 and Hypercapnia: r=0.50, P<0.01). Ventilatory responses were not different between groups. Conclusions: Muscle vasodilatation during peripheral and central chemoreceptors stimulation is blunted in patients with HF. This vascular response may be explained, at last in part, by the exaggerated MSNA responses during hypoxia and hypercapnia.