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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Pressure and time dependence of the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy

Full text
Author(s):
M.E.B. Otto [1] ; F.M. Consolim-Colombo [2] ; C.R.M. Rodrigues Sobrinho [3] ; E.M. Krieger [4]
Total Authors: 4
Affiliation:
[1] Universidade de São Paulo. Faculdade de Medicina. Instituto do Coração - Brasil
[2] Universidade de São Paulo. Faculdade de Medicina. Instituto do Coração - Brasil
[3] Universidade de São Paulo. Faculdade de Medicina. Instituto do Coração - Brasil
[4] Universidade de São Paulo. Faculdade de Medicina. Instituto do Coração - Brasil
Total Affiliations: 4
Document type: Journal article
Source: Brazilian Journal of Medical and Biological Research; v. 37, n. 11, p. 1615-1622, 2004-11-00.
Field of knowledge: Biological Sciences - Physiology
Abstract

The first minutes of the time course of cardiopulmonary reflex control evoked by lower body negative pressure (LBNP) in patients with hypertensive cardiomyopathy have not been investigated in detail. We studied 15 hypertensive patients with left ventricular dysfunction (LVD) and 15 matched normal controls to observe the time course response of the forearm vascular resistance (FVR) during 3 min of LBNP at -10, -15, and -40 mmHg in unloading the cardiopulmonary receptors. Analysis of the average of 3-min intervals of FVR showed a blunted response of the LVD patients at -10 mmHg (P = 0.03), but a similar response in both groups at -15 and -40 mmHg. However, using a minute-to-minute analysis of the FVR at -15 and -40 mmHg, we observed a similar response in both groups at the 1st min, but a marked decrease of FVR in the LVD group at the 3rd min of LBNP at -15 mmHg (P = 0.017), and -40 mmHg (P = 0.004). Plasma norepinephrine levels were analyzed as another neurohumoral measurement of cardiopulmonary receptor response to LBNP, and showed a blunted response in the LVD group at -10 (P = 0.013), -15 (P = 0.032) and -40 mmHg (P = 0.004). We concluded that the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy is blunted at lower levels of LBNP. However, at higher levels, the cardiopulmonary reflex has a normal initial response that decreases progressively with time. As a consequence of the time-dependent response, the cardiopulmonary reflex response should be measured over small intervals of time in clinical studies. (AU)

FAPESP's process: 01/00009-0 - An integrated approach for the dissection of primary hypertension: molecular and functional characterization of the cardiovascular system
Grantee:Eduardo Moacyr Krieger
Support Opportunities: Research Projects - Thematic Grants