房室结慢径区域消融对迷走神经功能及心房颤动易感性的影响

Objective Atrioventricular node reentrant tachycardia (AVNRT) ablation may effect the vagal response,which is indicated by sinus tachycardia. On the other hand,atrial fibrillation (AF) ,which was found to be associated with vagal irmervation, often coexists with AVNRT. However,little is known about the im-pact of slow pathway ablation on local vagal innervation to atria. Methods In 11 dogs, bilateral cervical sympa-thovagal trunks were decentralized and metoprolol was given to block sympathetic effects. Linear lesion was per-formed from coronary sinus (CS) ostium to the middle area of Koch triangle. Atrial effective refractory period(ERP) ,vulnerability window (VW) of AF, and sinus rhythm cycle length (SCL) were measured at high fight atrium (HRA),low right atrium (LRA), distal (CSd) and proximal CS (CSp) at baseline with and without vagal stimulation before and after ablation. The histological study was also performed. Results (1) SCL during vagal stimulation remained unchanged before and after ablation(107±19)bpm vs (108±8) bpm (P > 0.05). (2) After ablation, ERP during vagal stimulation remained unchanged at HRA (55±34) ms vs (69 ±37) ms (P >0.05),and decreased slightly at CSd (42±32) ms vs (55±30) ms (P =0.08). However,at LRA and CSp,ERP was significantly decreased after ablation (19±21) ms vs (66±24) ms (P <0.001) ; and (7± 18) ms vs (46±24) ms (P < 0.001), respectively. (3) AF was difficult to be induced at baseline before and after ablation in all sites (VW close to 0). While during vagal stimulation, after ablation VW of AF significantly decreased at LRA (1±3) ms vs (49±36) ms (P < 0.005) and CSp (10±12) ms vs (45±34) ms (P < 0.05) ,decreased slightly at CSd after ablation (35±37) ms vs (57±28) ms (P =0.07) ,and remained un-changed at HRA (63±31) ms vs (63±25) ms (P > 0.05). (4) The altered architecture of individual gan-glia was histologically observed. Conclusions The decreased ERP shortening to vagal stimulation in CS and LRA induced by slow pathway ablation indicates that ablation in such area may result in the vagal dennervation in LRA and CS,thereby attenuating the susceptibility to vagal mediated AF. While unchanged SCL,ERP short-ening and VW to vagal stimulation in sinus node area and HRA indicate that slow pathway ablation did not change the vagal innervation to these sites.

Impact of slow pathway ablation on vagal innervation and vulnerability to atrial fibrillation