Vagal stimulation produces non-uniform effects on the atrial refractory period, providing basic electrophysiological insights into autonomic influences on the atrium.
The refractory period (RP) was measured at several points on the right atrial surface in anesthetized dogs. Under control conditions with vagi cut the values recorded at various points varied by no more than 40 msec. During stimulation of the vagus nerves, singly or together, the RP varied widely. At some points marked effects were observed, while at others little or no effect was apparent. Reflex excitation of the vagi, induced by increased arterial pressure, yielded similar results. It was concluded that the effects of vagal stimulation are not uniformly distributed.
Alessi et al. (Fri,) studied this question.