Arrhythmias Produced by Cardiac Nervous Stimulation

The experiments on the arrhythmias induced by electrical stimulation of cardiac nerves provided the following observations and speculations.(1) The nodal tachycardia induced by sympathetic stimulation was of specific type. Atrial electrographic recording revealed that there existed interference dissociation at the level varying from within the A-V node, through the atrium to the S-A node, between sinus rhythm and nodal tachycardia with a rate almost equal to that of the sinus.(2) Functionally, the left sympathetic nerve seemed to distribute mainly in the A-V nodal tissue, while the right in the S-A node. The effect of the right, sympathetic stimulation on the A-V node, even if it was, might be masked by the more intensive response in the S-A node.(3) In the mechanism of the arrhythmias on central nervous stimula-tion, some other factors seemed to participate as well as direct neural excitation of the ectopic pacemaker.