The combined influence of the stimulus frequency of the vagal nerves and the atrial stimulus interval on the atrioventricular conduction time.
The way in which the A-V node adapts its conduction time to stepwise alterations of atrial stimulation rates was studied under different conditions of vagal nerve activity (open chest, anaesthetised rabbit). Increase of stimulation rate induced oscillatory adaptation to a longer conduction time. Decrease caused shorter conduction times without oscillation. The time constant did not differ. Oscillation amplitude and time constants were markedly influenced by vagal activity. The observed phenomena can be explained on the basis of a time and voltage dependent K+ conductance.
D000818:Animals; D016275:Atrial Function; D001283:Atrioventricular Node / Q000502:physiology*; D004558:Electric Stimulation; D006329:Heart Conduction System / Q000502:physiology*; D008297:Male; D011817:Rabbits; D013997:Time Factors; D014630:Vagus Nerve / Q000502:physiology*