Effect of left superior pulmonary vein fat pad on atrial fibrillation in dogs

Abstract

Objective To explore the effect of ablation of left superior pulmonary vein fat pad(LSPV-FP) on atrial fibrillation(AF).Methods Twelve healthy adult mongrel dogs were anesthetized and ventilated;both cervical vagosympathetic trunks were exposed for stimulation.Thoracotomies at the 4th intercostal space of left and right chest were performed to expose the LSPV-FP.The effective refractory period(ERP)/ERP-dispersion(dERP) of atrium and LSPV,AF inducibility,and the ventricular rate of AF were measured in the following statuses: baseline,vagosympathetic trunk stimulation(VTS),LSPV-FP ablation,and VTS post LSPV-FP ablation.Results At baseline status,stimulation of the left or right vagosympathetic trunks significantly shortened the ERP of atrial([84.44±29.50] ms vs [129.7±15.83] ms,[85.42±26.11] ms vs [129.7±15.83] ms,P0.05),increased the dERP of atrial([71.67±14.03] ms vs [34.17±18.32] ms,[57.5±24.17] ms vs [34.17±18.32] ms,P0.05),the difference of ERP between proximal and distal of LSPV(P0.05),AF inducibility([5.33±1.231] times vs [0.75±0.96] times,[4.67±1.155] times vs [0.75±0.96] times,P0.05),and deceased the ventricular rate of AF([143.6±22.42] beats/min vs [226.3±28.50] beats/min,[146.4±30.72] times/min vs [226.3±28.50] times/min,P0.05).LSPV-FP ablation significantly attenuated all the above electrophysiological changes induced by left VTS(P0.05),but showed no effects on those induced by right VTS.Conclusion Left vagosympathetic trunk plays an important role in the development and maintenance of AF partially through LSPV-FP.