In vivo papillary muscle responses to cardiac nerve stimulation.

Abstract

SummaryFrom strain gauge arches applied to the longitudinal surface of the APM and PPM of the dog's left ventricle, patterns of mechanical contraction were recorded in vivo during sympathetic nerve stimulation. Profound augmentatian in force of contraction characterized these responses to excitation of the right and left stellate ganglia. Direct electrical excitation of small cardiac branches distal to the caudal cervical ganglion induced differential inotropic and chronotropic actions, depending upon the particular branch stimulated. The PPM appears to receive its primary innervation from the left cardiac sympathetic nerves, whereas the APM is supplied by both the left and right sympathetics.