CHANGES IN RIGHT AND LEFT CORONARY ARTERY INFLOW WITH CARDIAC NERVE STIMULATION

Abstract

The effects of stimulation of the stellate ganglia and their cardiac branches on coronary inflow in the anesthetized, open-chest dog have been studied with the use of the rotameter (for recording mean rate of inflow) and the orifice meter (for recording phasic flow). Stimulation of these structures usually causes a considerable and sustained augmentation of left coronary inflow and a somewhat smaller increase in right coronary inflow. In no instance was a sustained reduction in flow observed. The increase in mean rate of flow is the resultant of a decreased inflow during systole and a proportionately larger increase in flow during diastole. Occasionally, the phasic redistribution of flow throughout the cycle is such that the net flow increase is quite small. The augmentation of coronary inflow is frequently accompanied by simultaneous elevation of aortic blood pressure and/or heart rate. However, observations that the inflow increases when these variables either do not increase spontaneously or are artificially kept at the control level, indicate that these factors alone are not an indispensable part of the mechanism by which coronary inflow is increased. The augmentation of coronary inflow is regarded as an indication of coronary vessel dilatation. The mechanism remains to be detd.