Impact Of Right Upper Pulmonary Vein Isolation On Parasympathetic Nerve

Purpose: Right upper pulmonary vein(RUPV) isolation is essential for interventional treatment of atrial fibrillation. Meanwhile, RUPV is very close to the epicardial fat pads thereby the efferent vagal innervation to atria.This study was to investigate the impact of RUPV isolation on vagal innervation to atria based on the hypothesis that RUPV isolation could result in the damage of the epicardia fat pad.Methods: 6 adult mongrel dogs under general anesthesia were involved in this study. Bilateral cervical sympathovagal trunks were decentralized. Metoprolol was given to block sympathetic effects. Multipolar catheters were placed into right atrium(RA), coronary sinus(CS). RUPV isolation was performed via trans-septal procedure. Atrial effective refractory period(ERP), vulnerability window(VW)of atrial fibrillation, and sinus rhythm cycle length( SCL) were measured with and without vagal stimuli before and after RUPV isolation.Results: Sinus arrest during vagal stimulation observed in all dogs, while sinus cycle length remained unchanged during vagal stimulation after RUPV isolation, it indicated that RUPV isolation eliminated vagal modulation to sinus node. ERP at base remained unchanged before and after RUPV isolation(85.00±24.29 vs 103.33±22.51 msec at RA,p=0.19; 90.00±15.49 vs 98.33±24.83 msec at CS,p=0.29), While ERP during vagal stimulation significantly increased after RUPV isolation(21.67±9.83 vs 95.00±16.43 msec at RA,p<0.001;33.33±25.03 vs 75.00±29.49 msec at cs,p<0.005), it indicated that RUPV isolation attenuated vagal tone. Atrial fibrillation was very difficult induced at baseline before and after RUPV...