Chemorreflex and ergorreflex response before introduction and after optimization of beta-blocker therapy in heart failure patients

• Grant number: 09/17457-8
• Support type: Regular Research Grants
• Duration: August 01, 2010 - July 31, 2012
• Field of knowledge: Biological Sciences - Physiology - Physiology of Effort
• Principal researcher: Guilherme Veiga Guimarães
• Grantee: Guilherme Veiga Guimarães
• Home Institution: Instituto do Coração Professor Euryclides de Jesus Zerbini (INCOR). Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Exercise intolerance has been related to the alterations from hemodynamics and neurohumoral systems by complex interaction between cardioreflexes in heart failure (HF). The central, peripheral chemorreflexes and ergoreflexes are thought to be responsible for hyperventilation at rest and exercise, contributing to dyspnea. Objectives: To evaluate the central and peripheral chemoreceptor function course and the ergoreflex by the alterations in the ventilatory response, the HF biomarkers profile before the drug treatment and after introduction and optimization of beta-blockers, and to elucidate the influence of the medication on the relief of the symptoms related to the heart failure. Method: There will be studied 25 patients of both genders, between 18 and 65 years old, with the diagnoses of heart failure for more than 3 months, NYHA functional class II-IV, left ventricular ejection fraction d 45%, sorted on the Heart Failure Clinic of the Heart Institute, and that have not began the use of beta-blockers. These patients might be in use of angiotensin conversion enzyme inhibitors (ACE inhibitors), angiotensin-receptor blockers, aldosteron antagonists. All subjects will be assessed by cardiopulmonary test, spirometry test, six-minute walk test with central and peripheral chemoreceptors sensibilizations and regional circulatory occlusion test, plasma cathecolamines and BNP-B analysis. All subjects will be undergo a standard drug medical treatment of the Institute, based on the Brazilian Cardiology Society Guidelines for diagnoses and treatment of heart failure with the introduction and optimization of beta-blocker therapy and, after six months, they will be reevaluated. (AU)