The influence of the autonomic system upon atrio-ventricular accessory pathways conductive performance

In this report, the influence of the autonomic nervous system on the accessory pathway (Kent and Mahaim fibers) is discussed, based on electrophysiological and centrifuge examination results in two military pilots. We demonstrated that catecholamines reduce the effective refractory period (ERP) and improve conductivity in both the atrio-ventricular node (A-V node) and the accessory pathway. We concluded that the pattern of intermittent preexcitation may be connected with phenomenon of the 3rd and 4th phase block of the functional potential in the accessory pathway, and that in some cases the +Gz gravitoinertial tolerance test performed on the human centrifuge may help in distinguishing subjects with the intermittent preexcitation syndrome. Finally we concluded that all pilots with preexcitation syndrome should be dismissed from flying.