Sympathetic neural effects on regional atrial recovery properties and cardiac rhythm.

The functional distribution of the cardiac sympathetic nerves to the atria and their arrhythmiogenic effects were determined in 16 open-chest pentobarbital-anesthetized dogs. Shortening of refractory periods at four right and two left atrial sites during stimulation of the nerves was taken as a criterion of their distribution. Stimulation of right stellate ganglion, craniovagal, and right stellate cardiac nerves produced localized shortening on the right atrium, particularly at the sinus node area, and invariably induced sinus tachycardia. The recurrent cardiac nerve produced little shortening at all sites and less arrhythmiogenic effect. The left stellate ganglion and ventrolateral cardiac nerve affected only left atrial sites and induced atrioventricular junctional rhythm. The ventromedial cardiac nerve affected all sites and had no consistent arrhythmiogenic effect. The innominate nerve had no substantial effect. We concluded that the functional distribution of the cardiac sympathetic nerves is localized, and that rate, rhythm, and refractory period changes induced by stimulation of these nerves are characteristic of the area of distribution.