Factorial analysis of the cardiovascular responses to carotid sinus nerve stimulation.

Abstract

The changes in arterial blood pressure, heart period, and respiration evoked by carotid sinus nerve (CSN) stimulation were studied in closed-chest, anesthetized dogs. Multifactorial regression equations were derived to express the various steady-state responses as functions of the parameters of stimulation. With the CSN and vagi intact, the changes in arterial pressure produced by CSN stimulation were much less pronounced than after the CSN and vagi were interrupted. When the CSN and vagi were intact, changes in stimulus duration had relatively little influence on heart period at the lower voltage levels. However, at higher voltages, increases in pulse duration produced substantial increments in heart period. TheRR interval increased progressively as the frequency of CSN stimulation was varied from 15 to 45 Hz; the magnitude of this effect varied directly with the stimulus voltage.