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Titolo:
Time delay of vagally mediated cardiac baroreflex response varies with autonomic cardiovascular control
Autore:
Keyl, C; Schneider, A; Dambacher, M; Bernardi, L;
Indirizzi:
Univ Regensburg, Med Ctr, Dept Anesthesiol, D-93042 Regensburg, Germany Univ Regensburg Regensburg Germany D-93042 , D-93042 Regensburg, Germany Fraunhofer Inst Phys Messtech, D-70110 Freiburg, Germany Fraunhofer Inst Phys Messtech Freiburg Germany D-70110 Freiburg, Germany Univ Pavia, Dept Internal Med, I-27100 Pavia, Italy Univ Pavia Pavia Italy I-27100 , Dept Internal Med, I-27100 Pavia, Italy Ist Ricovero & Cura Carattere Sci, I-27100 Pavia, Italy Ist Ricovero & Cura Carattere Sci Pavia Italy I-27100 27100 Pavia, Italy
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 1, volume: 91, anno: 2001,
pagine: 283 - 289
SICI:
8750-7587(200107)91:1<283:TDOVMC>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACUTE MYOCARDIAL-INFARCTION; HEART-RATE-VARIABILITY; RR-INTERVAL; ARTERIAL-PRESSURE; SPECTRAL-ANALYSIS; RATE TURBULENCE; OSCILLATIONS; REFLEX; MODULATION; MORTALITY;
Keywords:
autonomic nervous system; heart rate; neck suction; spectral analysis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Keyl, C Univ Regensburg, Med Ctr, Dept Anesthesiol, D-93042 Regensburg, Germany Univ Regensburg Regensburg Germany D-93042 2 Regensburg, Germany
Citazione:
C. Keyl et al., "Time delay of vagally mediated cardiac baroreflex response varies with autonomic cardiovascular control", J APP PHYSL, 91(1), 2001, pp. 283-289

Abstract

To examine whether changes in autonomic activity have an effect on the latency of the vagally mediated cardiac baroreflex response in humans, we investigated the effects of neck suction fluctuating sinusoidally at 0.2 Hz on R-R intervals (known to be mediated mainly by vagal activity) in the supineposition, during 15 degrees head-down tilt and 60 degrees head-up tilt, and during vagotonic (2 mug/kg) and vagolytic (10 mug/kg) doses of atropine while the subjects breathed at 0.25 Hz. The phase shift between fluctuationsin neck chamber pressure and in R-R interval was calculated by complex transfer function analysis and was used as a measure of the time delay betweencarotid baroreceptor stimulation and cardiac effector response. Cardiac baroreflex responsiveness increased significantly during low-dose atropine and decreased during head-up tilt or 10 mug/kg atropine. With increasing tiltangle, the time delay between cyclic baroreceptor stimulation and oscillations in R-R interval increased from 0.32 +/- 0.27 s (head down), to 0.59 +/- 0.25 s (supine position, P < 0.05 vs. head down), and to 0.86 +/- 0.27 s (head up, P < 0.01 vs. supine). Low-dose atropine had a similar effect to head-down tilt on baroreflex latency, whereas 10 mug/kg atropine increased the time delay markedly to 1.24 +/- 0.30 s. Our results demonstrate that changes in autonomic activity, generated either by gravitational stimulus or by atropine, not only affect baroreflex responsiveness but also have a majorinfluence on the latency of the vagally mediated carotid baroreceptor-heart rate reflex. The prolonged baroreflex latency during decreased parasympathetic function may contribute to an unstable regulation of heart rate in patients with cardiac disease.

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Documento generato il 22/01/20 alle ore 12:41:17