Reflex control of sympathetic activity during simulated ventricular tachycardia in humans

Ventricular tachyarrhythmias present a unique set of stimuli to arterial and cardiopulmonary baroreceptors by increasing cardiac filling pressures and decreasing arterial pressure. The net effect on the control of sympathetic nerve activity (SNA) in humans is unknown. The purpose of this study was t...

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Bibliographic Details
Published in:Circulation (New York, N.Y.) N.Y.), 1999-08, Vol.100 (6), p.628-634
Main Authors: SMITH, M. L, JOGLAR, J. A, WASMUND, S. L, CARLSON, M. D, WELCH, P. J, HAMDAN, M. H, QUAN, K, PAGE, R. L
Format: Article
Language:English
Subjects:
Action Potentials
Adult
Baroreflex - physiology
Biological and medical sciences
Blood Pressure - drug effects
Cardiac Catheterization
Cardiac dysrhythmias
Cardiac Pacing, Artificial
Cardiology. Vascular system
Cardiotonic Agents - pharmacology
Cardiovascular Agents - pharmacology
Cardiovascular Agents - therapeutic use
Heart
Humans
Medical sciences
Middle Aged
Nitroprusside - pharmacology
Peroneal Nerve - physiopathology
Phenylephrine - pharmacology
Reflex, Abnormal - physiology
Space life sciences
Sympathetic Nervous System - physiopathology
Tachycardia, Supraventricular - physiopathology
Tachycardia, Ventricular - physiopathology
Tilt-Table Test
Vasodilator Agents - pharmacology
Ventricular Dysfunction, Left - physiopathology
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Summary:Ventricular tachyarrhythmias present a unique set of stimuli to arterial and cardiopulmonary baroreceptors by increasing cardiac filling pressures and decreasing arterial pressure. The net effect on the control of sympathetic nerve activity (SNA) in humans is unknown. The purpose of this study was to determine the relative roles of cardiopulmonary and arterial baroreceptors in controlling SNA and arterial pressure during ventricular pacing in humans. Two experiments were performed in which SNA and hemodynamic responses to ventricular pacing were compared with nitroprusside infusion (NTP) in 12 patients and studied with and without head-up tilt or phenylephrine to normalize the stimuli to either the arterial or cardiopulmonary baroreceptors in 9 patients. In experiment 1, the slope of the relation between SNA and mean arterial pressure was greater during NTP (-4.7+/-1.4 U/mm Hg) than during ventricular pacing (-3.4+/-1.1 U/mm Hg). Comparison of NTP doses and ventricular pacing rates that produced comparable hypotension showed that SNA increased more during NTP (P=0.03). In experiment 2, normalization of arterial pressure during pacing resulted in SNA decreasing below baseline (P
ISSN:0009-7322
1524-4539
DOI:10.1161/01.CIR.100.6.628