ABSTRACT
The Long-term Thromboembolic Event Analysis in Atrial Fibrillation Patients With Radiofrequency Catheter Ablation Objective: To observe the thromboembolic event in atrial fibrillation (AF) patients with long-term successful radiofrequency catheter ablation (RFCA), and to study the relationship between thromboembolic event and CHA2DS2-VASC score in order to guide the anticoagulation strategy for AF patients. Methods: A total of 321 AF patients who received RFCA in our hospital from 2000-01 to 2009-05 were studied. There were 261 patients with paroxysmal AF and 60 with persistent AF, they were followed-up for (66.7±26.9) months. The patients were divided into 2 groups according to AF recurrence condition as Non-recurrence group, n=204 and Recurrence group, n=117. The relationship between thromboembolic event and CHA2DS2-VASC score was studied. Results: The Non-recurrence group had significantly lower rate of thromboembolism than that in Recurrence group (1.96% vs 7.69%), P=0.017. In both groups, the patients with CHA2DS2-VASC score Conclusion: The AF patients who received RFCA without AF recurrence in long-term follow-up had the lower rate of thromboembolic event, CHA2DS2-VASC score was important for evaluating such event. The patients with CHA2DS2-VASC score < 2 could consider stopping warfarin anticoagulation, while the patients with CHA2DS2-VASC score ≥ 2 might be beneifted for warfarin anticoagulation.
ABSTRACT
Objective Mechanisms of pulmonary vein isolation (PVI) for atrial fibrillation remain controversy.This study aimed to investigate the impact of PVI on vagal modulation to atria.Methods Eighteen adult mongrel dogs under general anesthesia were randomly divided into two groups.Bilateral cervical sympathovagal trunks were decentralized and sympathetic effects was blocked by metoprolol administration.Atrial electrical remodeling (AER) was established by rapid right atrial pacing at the rate of 600 bpm for 30 minutes.PVI was performed in group A.Atrial effective refractory period (ERP),vulnerability window (VW) of atrial fibrillation,and sinus rhythm cycle length (SCL) were measured at baseline and during vagal stimulation before and after atrial rapid pacing with and without PVI at fight atrial appendage (RAA),left atrial appendage (LAA),distal coronary sinus (CSd) and proximal coronary sinus (CSp).Results (1) Effects of PVI on vagal modulation:Shortening of SCL during vagal stimulation decreased significantly after PVI compared with that before PVI in group A (P＜0.001).Shortening of ERP during vagal stimulation decreaseed significantly after PVI compared with that before PVI (P＜0.05).VW of atrial fibrillation during vagal stimulation decreased significantly after PVI compared with that before PVI (P＜0.05).(2) Effects of PVI on AER:shortening of ERP before and after atrial rapid pacing increased significantly at baseline and vagal stimulation in group B compared with that in group A (P＜0.05).VW during vagal stimulation increased significantly after atrial rapid pacing in group B (P＜0.05).Conclusion PVI attenuates the vagal modulation to the atria,thereby decreases the susceptibility to atrial fibrillation mediated by vagal activity.PVI releases AER,which maybe contributes to the vagal denervation.Our study indicates that PVI not only can eradicate triggered foci but also modify substrates for AF.(J Geriatr Cardiol 2008;5:28-32)
ABSTRACT
Background Atrial electrical remodeling(AER)plays an important role in the pathogenesis and maintenance of atrialfibrillation.However,little is known about modulation of vagal activilty to AER.This study aimed to investigate the relationshipbetween vagal moduation and AER. Methods Twenty four adult mongrel dogs under general anesthesia were randomized into 3groups.Sympathetic activity was blocked by administration of metoprolol in 3 groups.The changes in vagal modulation to atria afterAER were observed in 10 dogs without vagal interruption in group A.The effects of vagal intervention on AER were investigated in 8dogs with administration of atropine in group B.The impact of aggressively vagal activity on AER was studied in 6 dogs with bilateralcervical vag sympathetic trunLks stimulation during AER in group C.Bilateral cervicall vagosympathetic trunks were decentralized.Multipolar catheters wereplaced into high right atria(RA),coronary sinus(CS)and rightventricle(RV).AER was induced by 600 bpmpacing through RA catheter for 30 minutes.Attial effective refractory period(ERP)and vulnerability window (VW)of atrial fibrillationwere measured with and without vagal stimulation before and after AER.Results In group A,ERP decreased significantly at baselineand during vagal stimulation after AER compared with that beforeAER(all P＜0.05).In group B,ERP remaind unchanged at baselineand vagal stimulation after AER compared with tbat before AER (all P＞0.05).In group C,ERP shortened significantly at baseline andvagal stimulation after AER compared with that before AER(all P＜0.05).ERP shortening after AER in Groups A and C increasedsignificantly than that in group B (all P＜0.05).Atrial fibrillation could not be induced at baseline(VW close to 0) before and after AERin three groups.VW became widen significantly during vagal stimulation after AER compared with that before AER in Groups A and C(all P＜0.05),while VW remained unchanged in group B (VW close to 0).Conclusions Short-term AER results in the decrease inERP.AER is accompanied by the increases in atrial vagal modulation.The increased vagal activity and vagal stimulation promote AER,thereby increase the susceptibility to atrial fibrillation.The interrupted vagal activity attenuates AER.thereby suppresses the atriaIfibrillation mediated by vagal stimutlation.