Selective AV nodal vagal stimulation improves hemodynamics during acute atrial fibrillation in dogs

Although the atrioventricular node (AVN) plays a vital role in blocking man y of the atrial impulses from reaching the ventricles during atrial fibrill ation (AF), a rapid irregular ventricular rate nevertheless persists. The g oals of the present study were to explore the feasibility of novel epicardi al selective vagal nerve stimulation for slowing of the ventricular rate du ring AF and to characterize the hemodynamic benefits in vivo. Electrophysio logical-echocardiographic experiments were performed on 11 anesthetized ope n-chest dogs. Hemodynamic measurements were performed during three distinct periods: 1) sinus rate, 2) AF, and 3) AF with vagal nerve stimulation. AF was associated with significant deterioration of all measured parameters (P < 0.025). The vagal nerve stimulation produced slowing of the ventricular rate, significant reversal of the pressure and contractile indexes (P < 0.0 25), and a sharp reduction in one-half of the abortive ventricular contract ions. The present study provides comprehensive evidence that slowing of the ventricular rate during AF by selective ganglionic stimulation of the vaga l nerves that innervate the AVN successfully improved the hemodynamic respo nses.