Heart Rate Deceleration Force In Patients With Vasovagal Syncope And Long - Term Efficacy Of Radiofrequency Catheter Ablation

Part Ⅰ:Quantative Evaluation of Parasympathetic Tone in Vasovagal Syncope Patients through Deceleration Capacity MeasurementBackground:There were no appropriate tools to specifically measure the cardiac parasympathetic innervation of vasovagal syncope patients. This study was designed to quantatively depict the abnormal cardiac parasympathetic tone by measuring deceleration capacity (DC) in vasovagal syncope patients.Methods:Thirty-eight drug refractory vasovagal syncope patients were consecutively enrolled (21 female; mean age,40.8±14.5 years). Thirty-eight age-and sex-matched healthy volunteers were recruited as control group. Longtime electrophysiological signals were collected from which overall deceleration capacity (ODC), daytime deceleration capacity (DDC), nighttime deceleration capacity (NDC) and heart rate variables were calculated. Receiver operating curve analysis (ROC) was performed to analyze the sensitivity and specificity values of ODC, DDC, NDC and heart rate variables in predicting vasovagal syncope.Results: ① ODC[(9.52±3.44)ms]、DDC[(8.86±3.37)ms] and NDC[(11.30±4.43)ms] in VVS group were significantly higher when compared with that of the control group, which were (6.11±1.83) ms、(5.54±1.71) ms and (7.58±3.45) ms, respectively, P 0.001; ② SDSD[(33.1±13.2) ms] and rMSSD[(30.7±13.4) ms] in VVS group were higher than SDSD[(27.0±6.4) ms] and rMSSD[(25.7±7.6) ms] in control group, P<0.05; ③ ROC analysis demonstrated that area under curve (AUC) of ODC, DDC and NDC curves were greater than 0.7 (P<0.001), while the AUC of SDSD and Rmssd were lower than 0.7 (P>0.05). The optimal cut-off value of ODC, DDC and NDC in predicting vasovagal syncope were 6.08 ms (sensitivity=89.5% and specificity=65.8%), 5.26 ms (sensitivity=94.7% and specificity=73.2%),7.02 ms (sensitivity=86.8% and specifity=73.2%), respectively.Conclusion:Deceleration capacity measurements served as quantative evaluation for the abnormal parasympathetic activity in vasovagal syncope patients. ODC, DDC and NDC could be used to predict the occurrence of VVS.Part Ⅱ:Impact of Left Atrial Ganglionated Plexi Denervation on Deceleration Capacity of Vasovagal Syncope PatientsBackground:Cardiac autonomous innervation of vasovagal syncope patients is featured with an abnormally elevated parasympathetic tone. Current body of literature lacked specific research concerning the impact of catheter ablation on cardiac autonomous function. This study used deceleration capacity measurement to evaluate the modification of left atrial ganglionated plexi denervation on cardiac autonomous innervation of vasovagal syncope patients.Methods:We consecutively enrolled thirty-five drug-refractory vasovagal syncope patients (age 41.3±14.2 y; 54.3% female). Anatomical-guided catheter ablation was targeted at five ganglionated plexus of the left atrium in all 35 patients. Overall deceleration capacity (ODC), daytime deceleration capacity (DDC) and nighttime deceleration capacity (NDC) were regularly repeated after the procedure. Recurrent syncope events were carefully documented during the follow-up period. Pearson’s correlation analysis was performed to evaluate the association between the inducibility of vagal response in each GP and deceleration capacity variables. Mixed linear effect model analysis was carried out to compare the differences of post-ablation ODC, DDC and NDC in patients with or without recurrent syncope.Results:A total number of 35 procedures were performed. In 30 patients vagal response was elicited and ablated in different GPs, including 30 LSGP,10 LLGP,14 LIGP,17 RAGP and 9 RIGP. There were five patients in whom none vagal response was induced in any GP site and these five patients experienced recurrent syncope after the procedure. According to Pearson’s correlation analysis, the inducibility of vagal response in each GP site demonstrated no correlation with baseline ODC, DDC and NDC (P<0.05). Meanwhile, vagal response induced in LSGP was negatively correlated with post-ablation ODC, DDC and NDC in different follow-up times (P<0.05) while RAGP vagal response was only negatively associated with the 1-day post-ablation ODC and DDC (P<0.05). Mixed linear effect model analysis revealed that post-ablation ODC, DDC and NDC differed significantly between patients with recurrent syncope and patients without recurrent syncope in each follow-up times (P<0.05).Conclusion:Anatomical-guided left atrial ganglionated plexi denervation prevented the majority of vasovagal syncope from recurring. The treatment demonstrated significant impact on the cardiac autonomous nerve system, especially the modification of parasympathetic nerve system.Part Ⅲ:Long-term Follow-up of Left Atrial Ganglionated Plexi Denervation as Treatment to Vasovagal SyncopeBackground:Autonomic modification through catheter ablation of ganglionated plexi (GP) in left atrium has been previously reported as alternative treatment for vasovagal syncope (VVS). The purpose of this study was to report the long-term clinical outcome in a larger cohort.Methods:We consecutively enrolled fifty-seven patients (age 43.2±13.4 years; female 35) with refractory VVS and performed high frequency stimulation (HFS) or anatomical-guided GP ablation in 10 and 47 cases, respectively. Survival analysis was performed. Changes of Deceleration capacity (DC), heart rate (HR), heart rate variable (HRV) measurements and head-up tilt test (HUT) were recorded.Results:A total number of 127 GP sites with positive vagal response were successfully elicited and ablated, including 52 left superior GP,19 left lateral GP,18 left inferior GP, 27 right anterior GP and 11 right inferior GP. During a follow-up of 36.4±22.2 (12-102) months, there were 52 (91.2%) patients who remained free from syncope. Prodromes recurred in 16 patients. No statistical differences were found between HFS-guided and anatomical-guided ablation groups in either freedom from syncope (100% vs 89.4%, P=0.348) or recurrent prodromes (50% vs 76.6%, P=0.167). DC, HR and HRV measurements demonstrated reduced vagal tone lasted for at least 12 months after ablation, with improved tolerance to repeated HUT. Transient sinus tachycardia occurred in one patient. No other complications were observed.Conclusion:LA GP ablation showed an excellent long-term clinical outcome and might be considered as therapeutic option in symptomatic VVS patients.