Document Detail

Dysregulation of peripheral and central chemoreflex responses in Chagas' heart disease patients without heart failure.
MedLine Citation:
PMID:  11591616     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The peripheral and central chemoreflexes are important autonomic mechanisms for regulating breathing and cardiovascular function. Although pathological inflammatory infiltration of the peripheral chemoreceptors and central nervous system has been reported in Chagas' disease, functional evaluation of chemoreflexes has not yet been performed. METHODS AND RESULTS: The hypothesis that chemoreflex function is altered in patients with Chagas' heart disease (CH) but normal left ventricle function was tested in 12 CH patients and 13 matched control subjects. The ventilatory rate, minute ventilation, heart rate, mean arterial pressure, forearm blood flow, forearm vascular resistance, and venous norepi-nephrine responses to hypoxia and hypercapnia were determined. During hypoxia, the decrease in oxygen saturation was smaller in CH patients, despite a similar ventilatory response between groups. Both groups showed an increase in heart rate during hypoxia, but this response was blunted in CH patients. Although the mean arterial pressure response to hypoxia was similar in both groups, forearm vascular resistance significantly decreased in control subjects while remaining unchanged in CH patients. Moreover, a significant increase in plasma norepinephrine levels elicited by stimulation of peripheral chemoreceptors was observed only in the CH group. During hypercapnia, the increase in minute ventilation was smaller in CH patients, who did not exhibit the increase in norepinephrine observed in control subjects. CONCLUSIONS: These data suggest that CH potentiates respiratory, cardiovascular, and autonomic responses to peripheral chemoreceptor activation by hypoxia in patients with normal left ventricular function. The ventilatory and sympathetic responses to central chemoreceptor activation by hypercapnia, however, are significantly blunted.
J A Soares Barreto-Filho; F M Consolim-Colombo; H Ferreira Lopes; C R Martins Sobrinho; G M Guerra-Riccio; E M Krieger
Related Documents :
7961246 - Effect of dopamine on hypoxic ventilatory response of sedated piglets with intact and d...
7124306 - Effect of supramaximal vagal stimulation in combination with hypoxia, respiratory acido...
7468246 - Effect of hypoxia on mechanical properties of isolated rat heart. comparison of the eff...
16050126 - Effect of prebiotic on gut development and ascites incidence of broilers reared in a hy...
7877306 - Triiodothyronine improves left ventricular function without oxygen wasting effects afte...
6228676 - The role of l-carnitine in the pathogenesis of cardiomegaly in patients with chronic he...
Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Circulation     Volume:  104     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2001 Oct 
Date Detail:
Created Date:  2001-10-09     Completed Date:  2001-12-04     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1792-8     Citation Subset:  AIM; IM    
Hypertension Unit, Heart Institute, InCor, University of São Paulo, São Paulo, Brazil.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Anoxia / physiopathology
Autonomic Nervous System Diseases / complications,  diagnosis,  physiopathology*
Blood Flow Velocity
Blood Pressure
Chagas Cardiomyopathy / complications,  physiopathology*
Chemoreceptor Cells / physiopathology*
Forearm / blood supply,  physiopathology
Heart Rate
Hypercapnia / physiopathology
Middle Aged
Norepinephrine / blood
Peripheral Nervous System Diseases / complications,  diagnosis,  physiopathology*
Pulmonary Ventilation
Reflex, Abnormal*
Vascular Resistance
Ventricular Function, Left
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Parasympathetic neural activity accounts for the lowering of exercise heart rate at high altitude.
Next Document:  Hypothermia after cardiac arrest: feasibility and safety of an external cooling protocol.