This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Soares Barreto-Filho, J. A. Articles by Krieger, E. M. Search for Related Content PubMed PubMed Citation Articles by Soares Barreto-Filho, J. A. Articles by Krieger, E. M. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Medline Plus Health Information Autonomic Nervous System Disorders Cardiomyopathy Chagas Disease Peripheral Nerve Disorders Related Collections Other heart failure Autonomic, reflex, and neurohumoral control of circulation

(Circulation. 2001;104:1792.)
© 2001 American Heart Association, Inc.

Clinical Investigation and Reports

Dysregulation of Peripheral and Central Chemoreflex Responses in Chagas’ Heart Disease Patients Without Heart Failure

José Augusto Soares Barreto-Filho, MD PhD; Fernanda Marciano Consolim-Colombo, MD PhD; Heno Ferreira Lopes, MD PhD; Carlos Roberto Martins Sobrinho, MD PhD; Grazia M. Guerra-Riccio, RN PhD; Eduardo Moacyr Krieger, MD PhD

From the Hypertension Unit, Heart Institute, InCor, University of São Paulo, São Paulo, Brazil.

Correspondence to Eduardo M. Krieger, MD, PhD, Hypertension Unit, Heart Institute, InCor, HCFMUSP, Av Dr Eneas de Carvalho Aguiar, 44, 05403-000 São Paulo, Brazil. E-mail edkrieger{at}incor.usp.br

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.

Key Words: hypoxia • hypercapnia • reflex • nervous system, autonomic • trypanosomiasis • Chagas’ disease

This article has been cited by other articles:

				D. F. Davila Sympathetic nervous system activation in chagasic patients with congestive heart failure J. Am. Coll. Cardiol., May 5, 2004; 43(9): 1723 - 1724. [Full Text] [PDF]

				J. A. S. Barreto-Filho, F. M. Consolim-Colombo, G. M. Guerra-Riccio, R. D. Santos, A. P. Chacra, H. F. Lopes, S. H. Teixeira, T. Martinez, J. E. Krieger, and E. M. Krieger Hypercholesterolemia Blunts Forearm Vasorelaxation and Enhances the Pressor Response During Acute Systemic Hypoxia Arterioscler Thromb Vasc Biol, September 1, 2003; 23(9): 1660 - 1666. [Abstract] [Full Text] [PDF]