Biomaterial Database

Vagal stimulation decreases rate of left ventricular relaxation. 1989

R J Henning, and J Cheng, and M N Levy

Division of Investigative Medicine, Mt. Sinai Medical Center, Cleveland, Ohio.

We determined the effects of vagal stimulation on the time constant (tau) of left ventricular isovolumic pressure decay and on the maximum rates of left ventricular pressure change (dP/dt) during contraction and relaxation in anesthetized dogs. In each dog, the atria were paced at a constant rate of 150 beats/min. We recorded left ventricular pressure waveforms in the absence (control) and in the presence of vagal stimulation at frequencies of 1, 2, and 3 Hz. During the control periods and during vagal stimulation at each frequency, we determined tau, the maximal rate of contraction, and the maximal rate of relaxation from left ventricular pressure waveforms recorded at medium (100 mmHg), high (130 mmHg), and low (73 mmHg) afterloads. Vagal stimulation at a frequency of 3 Hz increased tau by 23%. This effect of vagal stimulation on tau was most pronounced at the high afterload. Vagal stimulation at 3 Hz decreased the maximal rate of relaxation by 19%, but it decreased the maximal rate of contraction by only 8%. Thus vagal stimulation significantly decreased the rate of left ventricular relaxation and had a greater depressant effect on ventricular relaxation than on contraction.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009200	Myocardial Contraction	Contractile activity of the MYOCARDIUM.	Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014630	Vagus Nerve	The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).	Cranial Nerve X,Pneumogastric Nerve,Tenth Cranial Nerve,Nerve X,Nervus Vagus,Cranial Nerve, Tenth,Cranial Nerves, Tenth,Nerve X, Cranial,Nerve Xs,Nerve, Pneumogastric,Nerve, Tenth Cranial,Nerve, Vagus,Nerves, Pneumogastric,Nerves, Tenth Cranial,Nerves, Vagus,Pneumogastric Nerves,Tenth Cranial Nerves,Vagus Nerves,Vagus, Nervus
D016276	Ventricular Function	The hemodynamic and electrophysiological action of the HEART VENTRICLES.	Function, Ventricular,Functions, Ventricular,Ventricular Functions