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Titolo:
Dynamic regulation of heart rate during acute hypotension: new insight into baroreflex function
Autore:
Zhang, R; Behbehani, K; Crandall, CG; Zuckerman, JH; Levine, BD;
Indirizzi:
Presbyterian Hosp Dallas, Inst Exercise & Environm Med, Dallas, TX 75231 USA Presbyterian Hosp Dallas Dallas TX USA 75231 nm Med, Dallas, TX 75231 USA Univ Texas, SW Med Ctr, Dallas, TX 75231 USA Univ Texas Dallas TX USA 75231 iv Texas, SW Med Ctr, Dallas, TX 75231 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 1, volume: 280, anno: 2001,
pagine: H407 - H419
SICI:
0363-6135(200101)280:1<H407:DROHRD>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTRAL VENOUS-PRESSURE; BODY NEGATIVE-PRESSURE; BLOOD-PRESSURE; ARTERIAL-PRESSURE; CARDIOVASCULAR REGULATION; CAROTID BARORECEPTORS; PULSATILE PRESSURE; REFLEX; HUMANS; RESPONSIVENESS;
Keywords:
blood pressure; mathematical modeling;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Levine, BD Presbyterian Hosp Dallas, Inst Exercise & Environm Med, 7232 Greenville Ave, Dallas, TX 75231 USA Presbyterian Hosp Dallas 7232 GreenvilleAve Dallas TX USA 75231
Citazione:
R. Zhang et al., "Dynamic regulation of heart rate during acute hypotension: new insight into baroreflex function", AM J P-HEAR, 280(1), 2001, pp. H407-H419

Abstract

To examine the dynamic properties of baroreflex function, we measured beat-to-beat changes in arterial blood pressure (ABP) and heart rate (HR) during acute hypotension induced by thigh cuff deflation in 10 healthy subjects under supine resting conditions and during progressive lower body negative pressure (LBNP). The quantitative, temporal relationship between ABP and HRwas fitted by a second-order autoregressive (AR) model. The frequency response was evaluated by transfer function analysis. Results: HR changes during acute hypotension appear to be controlled by an ABP error signal between baseline and induced hypotension. The quantitative relationship between changes in ABP and HR is characterized by a second-order AR model with a pure time delay of 0.75 s containing low-pass filter properties. During LBNP, the change in HR/change in ABP during induced hypotension significantly decreased, as did the numerator coefficients of the AR model and transfer function gain. Conclusions: 1) Beat-to-beat HR responses to dynamic changes in ABP may be controlled by an error signal rather than directional changes in pressure, suggesting a "set point" mechanism in short-term ABP control. 2) The quantitative relationship between dynamic changes in ABP and HR can be described by a second-order AR model with a pure time delay. 3) The ability of the baroreflex to evoke a HR response to transient changes in pressure was reduced during LBNP, which was due primarily to a reduction of the static gain of the baroreflex.

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Documento generato il 07/08/20 alle ore 00:51:16