Functional distribution of the peripheral cardiac sympathetic pathways.

The functional peripheral cardiac sympathetic pathways of the dog were delineated in isovolumetric left ventricle preparations. In unpaced hearts, supramaximal stimuli at 2 cycles/sec to the right stellate ganglion caused the heart rate to increase 2.8 times more than stimuli applied to the left side. In paced hearts, such stimuli evoked rises in left ventricular systolic pressure which were 2.3 times greater when applied to the left than to the right stellate ganglion. Tonic cardiac sympathetic impulses appear to funnel through the stellate ganglia. Decentralization of the stellate ganglia abolished the ventricular responses to stimulation of the carotid baroreceptors and cephalic ischemia. Approximately two thirds of the tonic and baroreceptor reflex influences to the left ventricle entered the stellate ganglia from lower segments of the thoracic paravertebral chain, and one third entered from the communicating rami of the stellate ganglia. The ratio of the effects of complete decentralization of the left to those of decentralization of the right stellate ganglion was 1.6, both with respect to eliminating sympathetic tone and abolishing the baroreceptor reflex. ADDITIONAL