The Research Of The Relationship Between Autonomic Function Changes And The Recurrence After Atrial Fibrillation Radiofrequency Ablation

Background: Recent experimental and clinical studies show that the cardiacautonomic nerve system(ANS) plays an important role in the initiation andmaintenance of atrial fibrillation (AF). Once AF initiated, atrial electrical andstructural remodeling promotes its own maintenance and recurrences. In clinical,endocardial and/or epicardial ganglion plexus (GP) ablation including pulmonaryvein(PV) ablation damage to healthy myocardial tissue, and make the hyperactivity ofthe cardiac ANS to the damage of the ANS and suppressed. Whether autonomicdenervation reduce the paroxysmal atrial fibrillation recurrence rate and enhances thelong-term benefit after PV isolation(PVI) for atrial fibrillation (AF) is still underdiscussion. Objective: Through a retrospective study of radiofrequency ablation inpatients with paroxysmal atrial fibrillation(PAF), this study analysis the feature of theheart rate variability(HRV), explore the role of left atrial circumferential pulmonaryvein isolation(CPVI) of autonomic function and the relationship between autonomicfunction changes and the recurrence after atrial fibrillation radiofrequency ablation,find out the impact on ANS denervation for the efficacy of atrial fibrillation ablation.Methods: Part I: Influence of autonomic nerve system on the early recurrence ofatrial fibrillation after radiofrequency ablation of paroxysmal atrial fibrillation.A total of90paroxysmal atrial fibrillation patients with the average age of58±11(47～69) years underwent circumferential pulmonary vein ablation usingCARTO system in department of Cardiology, Chinese PLA General Hospital, fromFeb,2011to May,2012, using two or more anti-arrhythmic drug (AAD) ineffectivewith non-structural atrial fibrillation. All patients underwent24-hour ambulatoryHolter monitoring and heart rate variability (HRV) analysis3days before and afterthe ablation, respectively. Patients were divided into recurrence group (n=38) and non-recurrence group (n=52) based on the postoperative Holter results, symptoms andECG. The average heart rate (MeanHR), HRV including time domain index such asSDNN、SDANN、rMSSD、PNN50, and frequency domain index such as LF、HF、LF/HF of the two groups were compared. All patients underwent laboratory tests,12-lead ECG,24-hour Holter, chest radiography, transthoracic echocardiogram beforethe operation. All anti-arrhythmic drugs were discontinued at least5half-lives beforethe study, transesophageal echocardiography was performed in all patients except forleft atrial appendage and left atrial thrombus, and CT heart scans to determine theanatomy of the left atrium and pulmonary before1～2days of the ablation. Part Ⅱ:Comparative analysis of early recurrence and late recurrence of HRV afterAtrial fibrillation radiofrequency ablation. A total of82paroxysmal atrialfibrillation patients with the age of57.4±10.2(47～67)years underwent CPVI usingCARTO system from the period of Feb,2011to Aug,2012of cardiology department,Chinese PLA General Hospital. A11patients underwent24-hour ambulatory Holtermonitoring and heart rate variability (HRV) analysis3days before and after, and3,6,12months respectively after CPVI to analyze the heart rate variability. Patients weredivided into early recurrence group (n=34) and early non-recurrence group (n=48)based on the early postoperative Holter results, symptoms and ECG and were dividedinto late recurrence group (n=22) and late non-recurrence group (n=60) based on thepostoperative follow-up results. The average heart rate (MeanHR), HRV parameterswere recorded and compared. Any episode of tachycardia symptoms, or Atrialfibrillation, atrial flutter, atrial tachycardia identified on the surface ECG, or Atrialfibrillation, atrial flutter, atrial tachycardia lasting>30s in Holter monitoring during3days of the postoperation was considered to be the early recurrence. As a basis of it,patients were divided into early recurrence group and non-recurrent. A3-monthblanking period followed operation, after blanking period, Atrial fibrillation, atrialflutter, atrial tachycardia lasting>30were viewed as late recurrence. And patientswere divided into late recurrence group and non-recurrent group according to it.Results: Part I: Electrical isolation of the pulmonary veins was achieved in all the90patients.38of the90patients have atrial fibrillation, atrial flutter, atrial tachycardia, the early recurrence were42%. Clinical characteristics, MeanHR and HRVparameters before the operation in the2groups did not different significantly(P＞0.05). Postoperative and preoperative overall HRV indicators were significantly lower.HF indicted of parasympathetic tone was significantly lower, while LF/HF was higherand other HRV parameters decreased significantly in the non-recurrence group.Whereas, MeanHR increased, LF indicted of sympathetic tone significantly reduced,LF/HF reduced in the recurrence group.Difference was statistically significant(P＜0.05). Part Ⅱ: Electrical isolation of the pulmonary veins was achieved in all the82patients.34of the82patients had atrial fibrillation, atrial flutter, atrial tachycardia,the early recurrence were41%. During the13.5±10.5months follow-up,22patientshad atrial fibrillation, atrial flutter, atrial tachycardia, the late recurrence were27%.Clinical characteristics, MeanHR and HRV parameters of patients before theoperation in the2groups did not different significantly(P＞0.05). MeanHR decreases,the parameters of HRV decreased significantly and LF/HF increased in the earlypostoperative non-recurrence group. Whereas, only parasympathetic tone wassignificantly decreased and LF/HF increased in the late postoperative non-recurrencegroup. Conclusions:1、Both sympathetic and parasympathetic function decreasedsignificantly after CPVI of AF.2、Vagal denervation may inhabit early recurrence ofatrial fibrillation after left atrium CPVI in paroxysmal AF patients.3、Sustained vagaldenervation could also help prevent late recurrence of PAF in patients with CPVI.