Impact of Pulmonary Vein Anatomy on Long-term Outcome of Cryoballoon Ablation for Atrial Fibrillation

Variant pulmonary vein anatomy （PVA） has been reported to influence the recurrence of atrial fibrillation （AF） after radiofrequency ablation. However, the effects of PVA on AF in patients undergoing cryoballoon ablation （CBA） remain unknown. The present study aimed to examine the impact of PVA on the long-term outcome of CBA for AF. A total of 78 patients （mean age 60.7±10.9 years, 64.1% males） with symptomatic and drug-refractory paroxysmal AF were enrolled in the study. Left atrium （LA） and PVA acquired at computed tomography angiography （CTA） were reconstructed with CARTO 3 SYSTEM. Patients were routinely evaluated by 24-hour Holter monitoring following CBA. Cox regression was used to detect the predictors of AF recurrence after CBA. The results showed abnormal PVA in 30 patients （38.5%） and 18 patients （23.1%） had left common PV （LCPV）. Electrical pulmonary vein isolation was achieved in all patients. After a mean follow-up of 689.5±103.8 days, it was found that patients with abnormal PVA had similar AF recurrence rate to those with normal PVA （26.7% vs. 25.0%, P=0.54）, and there was no significant difference in AF recurrence rate between LCPV patients and non-LCPV patients （33.7% vs. 23.3%, P=0.29）. Cox regression analysis showed that AF duration （72.9±9.0 vs. 42.3±43.2 months, HR 1.001; 95%CI 1.003- 1.014; P〈0.001） and cryo-applications of right-side PVs （3.0±1.6 vs. 4.7±1.7, HR 0.661; 95% CI 0.473-0.925; P=0.016） were independent predictors of freedom from AF, but PVA was not identified as a predictor of long-term success. In conclusion, the variant PVA cannot significantly influence the long-term outcome of AF patients undergoing CBA; longer AF duration and less cryo-applications of right-side PVs are associated with higher AF recurrent rate.

Role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in cryoballoon ablation outcomes for paroxysmal atrial fibrillation

BACKGROUND Cryoballoon ablation(CBA)is recommended for patients with paroxysmal atrial fibrillation(AF)refractory to antiarrhythmic drugs.However,only 80%of patients benefit from initial CBA.There is growing evidence that pretreatment with angiotensin-converting enzyme inhibitors(ACEIs)and angiotensin receptor blockers(ARBs)decreases the recurrence of AF postablation,particularly in nonparoxysmal AF undergoing radiofrequency ablation.The role of ACEIs and ARBs in patients with paroxysmal AF in CBA remains unknown.We decided to investigate the role of ACEIs and ARBs in preventing the recurrence of atrial arrhythmia(AA)following CBA for paroxysmal AF.AIM To investigate the role of ACEIs and ARBs in preventing recurrence of AA following CBA for paroxysmal AF.METHODS We followed 103 patients(age 60.6±9.1 years,29%women)with paroxysmal AF undergoing CBA 1-year post procedure.Recurrence was assessed by documented AA on electrocardiogram or any form of long-term cardiac rhythm monitoring.A multivariable Cox proportional hazard model was used to assess if ACEI or ARB treatment predicted the risk of AA recurrence.RESULTS After a 1-year follow-up,19(18.4%)participants developed recurrence of AA.Use of ACEI or ARB therapy was noted in the study population.Patients on ACEI/ARB had a greater prevalence of hypertension and coronary artery disease.On a multivariate model adjusted for baseline demographics and risk factors for AF,ACEI or ARB therapy did not prevent recurrence of AA following CBA(P=0.72).Similarly,on Kaplan–Meier analysis pretreatment with ACEI/ARB did not predict the time to first recurrence of AA(P=0.2173).CONCLUSION In our study population,preablation treatment with an ACEI or ARB had no influence on the recurrence of AA following CBA for paroxysmal AF.

Long-term Outcomes after Second-Generation Cryoballoon Ablation of Atrial Fibrillation and Analysis of Risk Factors Related to Recurrence

Objective:This study is aimed to analyze the long-term safety and effectiveness of second-generation cryoballoon(CB2)ablation in the treatment of atrial fibrillation(AF).Methods:Data from 760 consecutive patients in the Department of Cardiology,General Hospital of Northern Theater Command from August 2016 to December 2018 with drug-refractory symptomatic AF undergoing pulmonary vein isolation(PVI)using CB2 were assessed.Procedure-related safety and freedom from AF and atrial flutter/atria tachycardia through 3 years were determined.The risk factors related to atrial tachyarrhythmia recurrence were analyzed.Results:Acute PVI was achieved in 100%of the 760 patients.Radiofrequency application for additional focal ablation was needed in 11(1.4%)patients and for 14 pulmonary veins(0.5%,14/(760×4))to achieve PVI.A total of 748 patients,including 539 with paroxysmal AF(PAF)and 209 with persistent AF(SAF)completed the follow-up,and only 12(1.6%)patients were lost.The mean follow-up duration was(19±8)months.The rate of major complications was 0.9%,including 0.8%of right phrenic nerve injury,which resolved before discharge.Freedom from all tachyarrhythmias was achieved in 75.0%,69.4%,and 63.2%of patients with PAF,respectively,at 12-,24-,and 36-month follow-up,and in 75.1%,67.4%,and 60.9%for SAF,with no significant differences between the PAF and SAF groups.AF course and the rate of body weight gain were independent risk factors for recurrence at 12 months after ablation(P=0.001 and P=0.009,respectively).Conclusion:PVI using CB2 has a high acute success rate and good safety in the treatment of PAF and SAF.Long course of AF and weight gain after ablation were independent risk factors for recurrence.

Pulmonary vein isolation implemented by second-generation cryoballoon for treating hypertrophic cardiomyopathy patients with symptomatic atrial fibrillation:a case-control study

Background Atrial fibrillation(AF)is a generally acknowledged turning-point of the natural history of hypertrophic cardiomyopathy(HCM);however,data from the cryoballoon ablation(CBA)for AF in HCM patients are relatively scarce.The study aimed to evaluate the efficacy and safety of CBA in HCM patients with AF.Methods We retrospectively analyzed HCM patients among 1253 patients with symptomatic AF who underwent CBA for pulmonary vein isolation in a single center.The study analyzed the AF recurrence and assessed the CBA indexes,including nadir temperature,time-to-isolation,CBA failure,pulmonary vein potentials(PVPs),and redo procedure.Results A total of 108 patients were included(mean age:59.0±6.9 years),27 patients(25%)had HCM,with the median follow-up duration of 25.5 months.The one-year AF-free rates were 79.0%vs.63.0%(non-HCM vs.HCM),while the two-year AF-free rates were 77.8%vs.55.1%[hazard ratio(HR)=2.758,log-rank P=0.024].Patients with persistent AF had poor AF-free rates compared to those with paroxysmal AF(P<0.001).The CBA failure was the most common in the right inferior pulmonary veins,which had the lowest PVPs.Multivariate Cox regression analysis indicated that HCM and persistent AF were risk factors for AF recurrence(HR=2.74,95%CI:1.29–5.79,P=0.008;and HR=3.97,95%CI:1.85–8.54,P<0.001,respectively).Conclusions The CBA can be effectively and safely used to treat HCM patients with symptomatic AF.The freedom from AF for HCM patients after CBA is relatively low compared to that for non-HCM patients.

Comparison of the efficacy and safety of pulmonary vein isolation using cryoballoon versus radiofrequency ablation for paroxysmal atrial fibrillation： An updated metaanalysis

Background Radiofrequency catheter ablation （RFCA） and cryoballoon ablation （CBA） are the two common ablation technologies used for the treatment of paroxysmal atrial fibrillation （PAF）. However, there is no consensus on which ablation method is the optimal choice. Methods We searched PubMed, EMBASE, Cochrane Library, Web of Knowledge and clinical trials.gov for clinically controlled trials （published up to January 11, 2017）. All included studies included fulfilled our previously defined criteria. The primary clinical outcome was the proportion of participants free from atrial fibrillation at 12-months follow-up. ; The secondary clinical outcomes were as the procedure time, fluoroscopy time, and total complications. Results We identified 573 studies, seven randomized controlled trials （RCTs） and 11 non-RCTs were included in this analysis （n=4982 participants）. Compared with RFCA, CBA had similar proportion of participants free from PAF at 12-months follow-up （70.8% vs. 69%; relative risk [RR] ： 1.01; 95% CI： 0.97 to 1.05）. Additionally, procedure time （149.61 vs. 174.73min; weighted mean difference WMD： 25.55; 95% CI： 44.69 to 6.41） was shorter in the CBA group, but the fluoroscopy time （34.52 vs. 38.59 min; WMD： 2.08; 95% CI： 5.86 to 1.71） did not have any significant difference. Total complication was not significantly different in both groups （RR： 1.22; 95% CI： 0.74 to 2.02 ）. Conclusions CBA is similar to RFCA with respect to clinical efficacy for PAF during the follow-up period of 12 months, and with no increased overall safety risk in the cryoballoon group CBA.

Effects of bronchial thermoplasty and cryoablation on airway smooth muscle

Background:The effectiveness of bronchial thermoplasty(BT)has been reported in patients with severe asthma.This study compared the effects of BT and cryoballoon ablation(CBA)therapy on the airway smooth muscle(ASM).Methods:Eight healthy male beagle dogs were included in this experiment.In the preliminary experiment,one dog received BT treatment for both lower lobe bronchus,another dog received CBA treatment for 7 s on the upper and lower lobe of right bronchus,and 30 s on the left upper and lower lobe.The treatments were performed twice at an interval of 1 month.In subsequent experiments,the right lower lobe bronchus was treated with BT,and the left lower lobe bronchus was treated with CBA.The effects of treatment were observed after 1(n=3)month and 6 months(n=3).Hematoxylin-eosin staining,Masson trichrome staining,and immunohistochemical staining were used to compare the effects of BT and CBA therapy on the ASM thickness,collagen fibers synthesis,and M3 receptor expression after treatment.One-way analysis of variance with Dunnett post hoc test was used to analyze the differences among groups.Results:In the preliminary experiment,the ASM ablation effect of 30-s CBA was equivalent to that of 7-s CBA(ASM thickness:30.52±7.75μm vs.17.57±15.20μm,P=0.128),but the bronchial mucociliary epithelium did not recover,and large numbers of inflammatory cells had infiltrated the mucosal epithelium at 1-month post-CBA with 30-s freezing.Therefore,we chose 7 s as the CBA treatment time in our follow-up experiments.Compared with the control group(35.81±11.02μm),BT group and CBA group(13.41±4.40μm and 4.81±4.44μm,respectively)had significantly decreased ASM thickness after 1 month(P<0.001).Furthermore,the ASM thickness was significantly lower in the 1-month post-CBA group than in the 1-month post-BT group(P=0.015).There was no significant difference in ASM thickness between the BT and CBA groups after six months(9.92±4.42μm vs.7.41±7.20μm,P=0.540).Compared with the control group(0.161±0.013),the average optical density of the ASM M3 receptor was significantly decreased in 6-month post-BT,1-month post-CBA,and 6-month post-CBA groups(0.070±0.022,0.072±0.012,0.074±0.008,respectively;all P<0.001).There was no significant difference in the average optical density of ASM M3 receptor between the BT and CBA therapy groups after six months(P=0.613).Conclusions:CBA therapy effectively ablates the ASM,and its ablation effect is equivalent to that of BT with a shorter onset time.A neural mechanism is involved in both BT and CBA therapy.