Impact Of Pulmonary Isolation On Autonomic Modulation In Patients With Long Pause Secondary To Atrial Fibrillation Termination

Aims: numerous studies have demonstrated that automatic nerve system play an important role in initiation perpetuation of atrial fibrillation(AF). Denervation by catheter ablation results in the decreased recurrence of AF after ablation. More and more evidence shave shown that the long pause secondary to AF termination may be due to the increased vagal modulation. Vagal denervation by ablation may be one of mechanisms that eradicate long pause. Additionally, vagal denervation has been applied to treat the vagal vessel syncope. This study aimed to investigate the impact of catheter ablation for AF with long pause on autonomic modulation by heart rate viability(HRV)analysis, meanwhile compare it with AF without long pause.Methods: 40 patients with paroxysmal atrial fibrillation accompanied by long pause who had undergone catheter radiofrequency ablation has been recruited into the study,and 40 cases undergone AF ablation whose factors such as age, gender and so on matched were taken into the control group. Holter was performed before and 3 days after ablation. Heart rate, indexes of HRV(SDNN, PNN50,SDANN) and frequency indexes(HF,LF,ULF,VLF) were measured. Other indexes including echocardiography,CT scanner, age, gender, drug history, underlying diseases, history of atrial fibrillation and ablative results were analyzed. Based on follow up, all patients were divided into recurrence sub-group and non-recurrence sub-group.The difference of HRV before andafter ablation was compared, and the difference of HRV between recurrence sub-group and non-recurrence sub-group was also compared.Results:(1)No significance of age, gender, history of atrial fibrillation, underlying disease,and echocardiography results have been observed between the two groups(P > 0.05).(2)No significance of age, gender, history of atrial fibrillation, underlying disease,and echocardiography results have been observed between the two groups(P > 0.05).(3)Changes of HRV before or after ablation between long pause group and the non-long pause group, HRV decreased after ablation, while heart rate increased. The regulation function of automatic nerve in long pause group was stronger than those without long pause(P<0.05).(4)HRV remained unchanged in AF recurrent patients in two group,especially in AF with long pause group(P > 0.05), while, HRV has a little change in AF without long pause group).In AF non-recurrent patients, HRV parameters decreased significantly after ablation in two group(P < 0.05).HRV changes before and after ablation in AF with long pause were more aggressive, compared with that in patients without long pause.Conclusions:( 1) Catheter ablation for atrial fibrillation results in cardiac denervation. The autonomic modulation in patients with paroxysmal atrial fibrillation accompanied by long pause is stronger than that in patients without long pause. Changes of HRV due to ablation are more aggressive in AF with long pause than that in patients without long pause.( 2) The automatic modulation for patients with paroxysmal atrial fibrillation accompanied by long pause may be play more important role than that for patients without long pause. It indicates that denervation by ablation may be more effective for prevention of AF recurrence for patients with long pause.