Chronic Cardiac Neurostimulation for Ventricular Rate Control During Atrial Fibrillation

Abstract

The inferior interatrial ganglionated parasympathetic plexus (IIGP) almost exclusively innervates the atrioventricular node. Acute intracardiac stimulation of this plexus with electrode catheters has been shown to decrease the ventricular rate during atrial fibrillation (AF) in humans. The present study reports on the 6 months stimulation effects of a permanent neurostimulation lead which has been implanted transvenously into this IIGP in dogs. In 5 dogs a DDD-pacemaker was implanted and AF induced by rapid pacing. During 6 months intermittent high frequency stimulation of the IIGPP was performed over a second implantable stimulator to assess chronic neurostimulation efficacy. From 1 to 6 months a continuous decrease of the voltage at which atrioventricular block III° could be elicited was observed. At implant/6 months a 1.8/2.5-fold prolongation of the RR interval during AF was achieved at 1 V/1 ms. Dynamic modulations of the magnitude of the negative dromotropic effect could be obtained by varying stimulus frequency, voltage and duration. Selective chronic cardiac neurostimulation for ventricular rate control during AF can be achieved in animals. The results obtained so far justify human studies.