Oscillatory nature of AV nodal pacemaker activity.

The perfusion of the AV node artery in dog heart in vivo was performed. After destroying the sinoatrial node by selective injection of ethanol into the sinus node artery, the selective administration of catecholamines into the AV node artery induced acceleration of nodal rhythm. In the course of recovery, eminent oscillatory change in the AV nodal rhythm was regularly observed. This oscillatory change was not blocked by atropine, phenoxybenzamine and tetrodotoxin. These results led to the conclusion that the oscillatory response of the AV node to catecholamines might be probably an inherent property of AV node pacemaker itself.