AUTONOMIC MODULATION OF THE INTERACTION BETWEEN THE INPUTS TO THE ATRIOVENTRICULAR NODE

The existence and the functional importance of multiple atrial inputs into the atrioventricular node influencing conduction is now well recognized. The predominant excitation wave front entering the node through the crista terminalis or via the interatrial septum appears to determine variations in the conduction pattern. Successful summation of the inputs can enhance conduction while cancellation may result in A-V nodal block. Functional reentry circuits utilizing the dual inputs have also been observed. The focus of this study addresses the influence of the autonomic nervous system on the interaction between these atrioventricular nodal inputs which appear to engender an indirect mechanism for regulation of conduction in addition to the direct chronotropic and dromotropic effects.