Severe hypoxemia after radiofrequency ablation for atrial fibrillation in palliatively repaired tetralogy of Fallot: A case report

BACKGROUND Patients with tetralogy of Fallot(TOF)often have arrhythmias,commonly being atrial fibrillation(AF).Radiofrequency ablation is an effective treatment for AF and does not usually cause severe postoperative hypoxemia,but the risk of complications may increase in patients with conditions such as TOF.CASE SUMMARY We report a young male patient with a history of TOF repair who developed severe hypoxemia after radiofrequency ablation for AF and was ultimately confirmed to have a new right-to-left shunt.The patient subsequently underwent atrial septal occlusion and eventually recovered.CONCLUSION Radiofrequency ablation may cause iatrogenic atrial septal injury;thus possible complications should be predicted in order to ensure successful treatment and patient safety.

Value of cystatin C in predicting atrial fibrillation recurrence after radiofrequency catheter ablation

Backgroud Recent studies have demonstrated that cystatin C is a valuable risk marker for cardiovascular disease morbidity and mortality.Therefore,we hypothesized that the pre-ablation cystatin C level was associated with post-ablation atrial fibrillation(AF)recurrence.Methods 207 patients were enrolled and completed in this prospective observational study.Patients with AF scheduled for receive radiofrequency catheter ablation(RFCA)therapy were screened for the study.Before ablation therapy,electrocardiogram,24 h holter monitor,transesophageal echocardiography,serum cystatin C,high-sensitivity C-reactive protein,creatinine levels,and routine blood examinations were examined.After ablation,patients were followed up every week for the first month,and then at 2,3,6,9,and 12 months.Thereafter,patients came back to out-patient clinic every six months regularly.Electrocardiogram or 24 h holter monitor were repeated if the patient experienced palpitations or every six months.AF recurrence was defined as atrial flbrillation/atrial flutter or atrial tachycardia lasting≥30 seconds within three months after therapy.Results Compared to patients with no AF recurrence,patients with recurrence had longer AF history(P=0.007),more early recurrence(P=0.000),a larger left atrium(P=0.004),and higher pre-ablation cystatin C levels(P=0.000).Multivariate regression analysis revealed that cystatin C and left atria(LA)diameter were risk factors for AF recurrence.After adjusting for LA diameter,the risk of AF recurrence increased 30%with every milligram cystatin C elevation(95%CI:1.117-1.523).Conclusions Pre-ablation cystatin C levels were associated with AF recurrence after RFCA therapy,an optimal cut-off value of 1.190 mg/L(sensitivity=0.576;specificity=0.851).

Catheter ablation of atrial fibrillation: Radiofrequency catheter ablation for redo procedures after cryoablation

AIM: To evaluate the effectiveness of two different strategies using radiofrequency catheter ablation for redo procedures after cryoablation of atrial fibrillation.METHODS: Thirty patients(paroxysmal atrial fibrillation: 22 patients,persistent atrial fibrillation: 8 patients) had to undergo a redo procedure after initially successful circumferential pulmonary vein(PV) isolation with the cryoballoon technique(Arctic Front Balloon,CryoCath Technologies/Medtronic).The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy(CARTO;Biosense Webster) depending on the intra-procedural findings.After discharge,patients were scheduled for repeated visits at the arrhythmia clinic.A 7-day Holter monitoring was performed at 3,12 and 24 mo after the ablation procedure.RESULTS: During the redo procedure,a mean number of 2.9 re-conducting pulmonary veins(SD ± 1.0 PVs) were detected(using a circular mapping catheter).In 20 patients,a segmental approach was sufficient to eliminate the residual pulmonary vein conduction because there were only a few recovered pulmonary vein fibres.In the remaining 10 patients,a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction.All recovered pulmonary veins could be isolated successfully again.At 2-year follow-up,73.3% of all patients were free from an arrhythmia recurrence(22/30).There were no major complications.CONCLUSION: In patients with an initial circumferential pulmonary vein isolation using the cryoballoon technique,a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation.

Hemoptysis secondary to pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation: A case report and literature review

Objectives: Pulmonary vein stenosis(PVS) is a known complication after radiofrequency ablation of atrial fibrillation(RAAF) and is often misdiagnosed owing to lack of awareness regarding PVS among noncardiologists.Misdiagnosis results in unnecessary treatment;therefore, greater understanding of PVS can improve the management of these patients.Methods: We report the case of a 38-year-old man with a history of RAAF who presented with massive hemoptysis.His symptoms persisted despite undergoing transcatheter bronchial artery embolization on two occasions.Results: Pulmonary computed tomography angiography revealed a completely occluded left superior pulmonary vein. Considering the patient’s history of RAAF, we diagnosed him with RAAF-induced PVS and performed left superior lobectomy after which hemoptysis did not recur.Conclusions: Unexplained massive hemoptysis should alert clinicians regarding the possibility of RAAF-induced PVS. Balloon angioplasty and stent placement are used to treat PVS;however, their efficacy is controversial considering the high recurrence rates associated with these interventions.

Endoscopic management of an esophagopericardial fistula after radiofrequency ablation for atrial fibrillation

A case is reported of a 76-year-old man with a past history of atrial fibrillation. A radiofrequency ablation procedure was suggested following several failed cardioversion attempts. However, an esophagopericardial fistula complicated the procedure. This life-threatening complication was successfully managed using both the placement of a covered esophageal stent and surgical pericardial and mediastinal drainage. In fact, no persisting fistula could be detected when the esophageal stent was removed seven weeks later. Atrioesophageal and esophagopericardial fistulas are two of the most severe complications associated with cardiological radiofrequency ablation procedures. They are responsible for majority of the deaths associated with this procedure. Despite the extremely high morbimortality associated with cardiothoracic surgery in such conditions, this treatment is the gold-standard for the management of such complications. This case report emphasizes the importance and efficacy of the endoscopic approach as part of a multidisciplinary management approach to this serious adverse event following radiofrequency ablation for atrial fibrillation.

The correlation between MFAP4 and recurrence and clinical outcome of atrial fibrillation after radiofrequency catheter ablation

Objective:To investigate the correlation between Microfibrillar-associated protein 4(MFAP4)and recurrence and clinical outcome of atrial fibrillation(AF)after radiofrequency catheter ablation(RFCA).Methods:A total of 101 patients with AF admitted to our department from December 2018 to January 2020 were treated with RFCA.The average follow-up period was(11.91±0.38)months.They were divided into recurrence group and non-recurrence group according to whether they had recurrence of AF.The levels of MFAP4,transforming growth factor-β1(TGF-β1),cardiac ultrasound indexes,body mass index(BMI)and major cardio-cerebral vascular events were compared between the two groups.The receiver operating characteristic(ROC)curve was drawn to analyze the predictive value of MFAP4 for recurrence of AF after RFCA.Results:The levels of MFAP4,TGF-β1,left atrial diameter(LAD)and BMI in the recurrent group were higher than those in the non-recurrent group(P<0.05).The left ventricular ejection fraction(LVEF)in the recurrent group was lower than that in the non-recurrent group(P<0.05).The levels of MFAP4,TGF-β1 and LAD in the patients of recurrent paroxysmal AF and persistent AF after RFCA were higher than those in the respective non-recurrent patients(P<0.05).MFAP4 was positively correlated with TGF-β1 and LAD(P<0.05).Logistic regression analysis showed that MFAP4,TGF-β1,and LAD were independent risk factors for recurrence of AF after RFCA.The ROC curve analysis showed that the area under the ROC curve of MFAP4 for predicting recurrence of AF after RFCA was 0.888(P=0.000),and the optimal cut-off value was 19.295ng/ml,with a sensitivity of 77.3%and a specificity of 77.2%.The incidence of readmission and total adverse events in recurrence group was significantly higher than that in non-recurrence group(P<0.05).Conclusions:MFAP4 was significantly increased in patients with recurrence after RFCA of AF,which was one of the independent risk factors for recurrence after RFCA of AF,and had certain clinical application value.

Mechanisms and clinical significance of early recurrences of atrial arrhythmias after catheter ablation for atrial fibrillation

Early recurrence of atrial arrhythmias(ERAA) after ablation is common and strongly predicts late recurrences and ablation failure. However, since arrhythmia may eventually resolve in up to half of patients with ERAA, guidelines do not recommend immediate reintervention for ERAA episodes occurring during a 3-mo postablation blanking period. Certain clinical demographic, electrophysiologic, procedural, and ERAA-related characteristics may predict a higher likelihood of longterm ablation failure. In this review, we aim to discuss potential mechanisms of ERAA, and to summarize the clinical significance, prognostic implications, and treatment options for ERAA.

Segmental radiofrequency ablation of pulmonary vein ostia for patients with refractory paroxysmal atrial fibrillation using multi-slice spiral computed tomography guidance

Objective： To evaluate the safety and clinical efficacy of segmental radiofrequency ablation of pulmonary vein （PV） ostia for patients with refractory paroxysmal atrial fibrillation （AF） under multi-slice spiral computed tomography （MSCT） guidance before the procedure. Methods： A series of 58 consecutive patients with refractory paroxysmal AF were enrolled to undergo segmental radiofrequency ablation ofPV ostia. The 36 male and 22 female patients with mean age of （57.4±9.5） （32-79） years and no obvious organic heart disease. Before ablation, patients received MSCT to generate 3-dimentional image of the left atrium （LA） and proximal PVs. Patients then underwent segmental radiofrequency ablation ofPV ostia using PV circular mapping catheter manipulated several times to ensure complete isolation between PVs and LA. Results： No complications occurred during the procedure. One patient developed delayed cardiac tamponade, which was drained percutaneously. The mean follow-up time was （17.1±9.3） months. Forty-one patients （95%） experienced improved quality of life one month after the procedure. Thirty-six patients （83%） showed stable sinus rhythm, while 10 patients （23%） required additional anti-arrhythmic drugs. AF returned≥1 time in 6 （14%） patients who underwent anti-arrhythmic drug therapy, but the number of episodes was less than that before the procedure. However, one patient experienced recurrent episodes of atrial flutter. Conclusion： It is safe and effective to perform segmental radiofrequency ablation of PV ostia for patients with refractory paroxysmal AF using MSCT guidance mappening.

Clinical outcomes of radiofrequency catheter ablation of atrial fibrillation in octogenarians lO-year experience of a one high-volume center

Background Prevalence of atrial fibrillation （AF） increases with age. Radiofrequency catheter ablation （RFCA） is an establishedtreatment option superior to antiarrhythmics （AAs）. In this study, we investigated safety and efficacy of RFCA of AF in octogenarians.Methods From our database, we extracted procedural and follow-up data for patients 〉 80 years with symptomatic AF undergoing RFCAand compared this population to RFCA patients 〈 50 years. All patients underwent pulmonary vein isolation （PVI） supplemented by linearlesions in PVI-nonresponders. Arrhythmia-free survival was assessed using seven day Holter every three months post procedure. All patientscompleted their 12 months follow-up. Results Fifty patients aged ≥80 years （80.5 ± 1.6 years） were compared to 259 patients aged 〈 50years （43.5±5.5 years）. The RFCA complication rate did not vary between groups. No differences in procedural characteristics were seenafter being analyzed by type of AF. Among patients with paroxysmal AF, 71.4% octogenarian vs. 84.7% young patients was free of anyarrhythmia, without AAs, after single procedure. For non-paroxysmal AF, arrhythmia-free survival without AAs, was considerably lower（58.6% octogenarians vs. 81.2% younger patients, P = 0.023）. If AAs were used, arrhythmia-free survival for paroxysmal AF increased to90.5% and 92.1% in octogenarians and younger patients, respectively; and in non-paroxysmal AF it increased to 79.3% vs. 88.4%. ConclusionsRFCA is a safe and effective strategy to achieve normal sinus rhythm in a highly selected group of octogenarians. Paroxysmal AF ablation inoctogenarians has similar clinical effectiveness as that seen in much younger patients. Non-paroxysmal AF ablation has lower, but still rea-sonable clinical effectiveness.

Comparison of long-term outcome between patients aged 〈 65 years vs. ≥ 65 years after atrial fibrillation ablation

Background Atrial fibrillation （AF） is the most frequent arrhythmia, and its prevalence is increasing with aging. We aimed to com-pare the long-term outcome data of patients 〈 65 years vs.≥ 65 years who underwent catheter ablation （CA） for drug-refractory AF. MethodsConsecutive patients with primary pulmonary vein isolation performed between March 2001 and December 2011, and those who completeda five-year of follow-up were divided into two groups： patients aged 〈 65 years into group 1, and patients aged ≥ 65 into group 2. Long-termoutcome data concerning mortality, thromboembolic events （TE） and success rates were compared between these groups. Results A totalnumber of 390 patients were included, group 1 contained 310 patients, and 80 patients in group 2. In group 2, patients had more often impairedrenal function （P 〈 0.001） and thyroid disease （P = 0.047）. A total of fifteen patients died during the 6.63 ± 2.1 years of follow-up, with a sig-nificantly higher incidence in the older group （8/80 vs. 7/310 patients, P = 0.004）. The majority of fatal outcome was due to cancerous dis-eases in both groups. No difference was observed concerning the long-term TE rate （12/310 vs. 4/80 patients, P = 0.75）. Rhythm controlfailed in 25.9% of the patients, with no difference between the groups： 26.4% in group 1 vs. 23.7% in group 2 （P = 0,67）, ConclusionsDespite growing prevalence of AF in aging population, the elderly patients are underrepresented in CA procedures. Similar clinical successand TE complication rate are observed between the age-groups. Our data suggest more liberal criteria might be applied while selecting pa-tients for AF ablation.

Modified Maze lines plus pulmonary vein isolation created by radiofrequency catheter ablation on the atrial wall to treat atrial fibrillation in elderly

Objective To evaluate the effect of modified Maze lines plus pulmonary vein (PV) isolation created by radiofrequency catheter ablation (RFCA) on atrial wall guided by a novel geometry mapping system in the treatment of elderly patients with paroxysmal atrial fibrillation (PAF). Methods After regular electrophysiological study, transseptal punctures were achieved twice with Swartz L1 and R1 sheaths. PV angiographies were conducted to evaluate their orifices and branches. A balloon electrode array catheter with 64 electrodes was put in the middle of the left atrium. Atrium geometry was constructed using Ensite 3000 Navx system. Two RFCA lesion loops and three lines (modified Maze) were created on left and right atrial walls. Each lesion point was ablated for 30 seconds with preset temperature 50 (ae) and energy 30W. The disappearance or 80% decrease of the amplitude of target atrial potential and 10 to 20(|), decrease of ablation impedance were used as an index of effective ablation. Results A total of 11 patients (7 male and 4 female, mean age, 68.7±5.1 years) were enrolled. PAF history was 7.9±4.5 years. PAF could not be prevented by mean 3.1±1.6 antiarrhythmic agents in 6.3±3.4 years. None of the patients had complications with structural heart disease or stroke. Left atrial diameter was 41.3±3.6 mm and LVEF was 59.2±3.7% on echocardiography. Two loops and three lines were completed with 67.8±13.1 (73-167) lesion points. Altogether 76-168 (89.4±15.3) lesion points were created in each patient. PAF could not be provoked by rapid burst pacing up to 600 beat per minute delivered from paroxysmal coronary sinus electrode pair.Complete PV electrical isolation was confirmed by three-dimensional activation mapping. Mean procedure time was 2.7±0.6 hours and fluoroscopy time was 17.8±9.4 minutes. Patients were discharged with oral aspirin and without antiarrhythmic agents. During follow up of 6.5±1.8 months, seven patients were PAF symptom free (63.6%). PAF attacks were decreased more than 70% in two patients (18.2%). PAF frequency did not change in another two patients (18.2%). Conclusions Ensite 3000 Navx guided modified Maze lines plus PV isolation on the atrial wall is safe and feasible in the elderly patients. It has the advantages of exact procedural endpoint, shorter X-ray exposure, fewer complications and satisfied long-term effect PAF control.

Comparison of the Outcomes of Monopolar and Bipolar Radiofrequency Ablation in Surgical Treatment of Atrial Fibrillation

Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency(RF) ablation used during cardiac surgery to treat atrial fibrillation.Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011.Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation,respectively.The sinus rhythm restoration rate,the procedural duration,the frequency of severe perioperative complications,and mortality were compared between the two groups.Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months(P=0.199).The frequencies of severe perioperative complications and mortality were also similar in the two groups.The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation(19.7±4.6 minutes vs.28.1±8.5 minutes,P< 0.001).Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery,but bipolar RF ablation is more convenient in practice.

RADIOFREQUENCY CATHETER ABLATION OF PERMANENT ATRIAL FIBRILLATION UNDER GUIDANCE OF CARTO-MERGE TECHNIQUE

Objective To investigate the feasibility and effectiveness of radiofrequency catheter ablation (RFCA) to treat permanent atrial fibrillation (AF) under the guidance of Carto-Merge technique. Methods Fifteen male patients with permanent AF underwent RFCA under the guidance of Carto-Merge technique. The mean age was 54.00±10.44 years, and duration of AF was 23.66±14.93 months. Cardiac magnetic resonance angiography (MRA) was performed to obtain pre-procedural three-dimensional (3D) images on the anatomy of left atrium (LA) and pulmonary veins (PVs) before RFCA procedure. Then the electroanatomical map was integrated with 3D images of MRA to form Carto-Merge map that guided step-by-step ablation strategy of permanent AF. Circumferential PV ablation was performed first until complete PVs electric isolation confirmed by Lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced. Results The episodes of AF were terminated during RFCA in 2 patients, by direct current cardioversion in the remaining 13 patients. Transient AF occurred in 2 patients after ablation on 1st day and 1st week respectively, AF terminated spontaneously not long after taking metoprolol. One patient developed persistent atrial flutter (AFL) in 2 months after procedure and AFL was eliminated by the second ablation. Persistent AF recurred on 1st day, 1st and 5th week respectively in 3 patients, and did not terminate after 3 months even though amiodarone was given. The remaining 12 patients were all free of AF during 2-11 months of follow-up. The recent success rate for RFCA of permanent AF was 80%. Conclusions Carto-Merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping, lower expenses, and enhance the success rate of RFCA of permanent AF.

Long-term stroke rates after catheter ablation or antiarrhythmic drug therapy for atrial fibrillation： a meta-analysis of randomized trials

Background Atrial fibrillation （AF） is an independent risk factor for ischemic stroke and is associated with increased risk of death. Randomized studies suggest improved quality of life for patients with AF after successful catheter ablation compared to antiarrhythmic drug therapy. The value of ablation in long-term risk of ischemic stroke, however, has not been assessed. We conducted a meta-analysis to determine whether AF ablation reduces the long-term risk of stroke compared to antiarrhythmic drug therapy in randomized controlled trials. Methods ＆ Results PubMed and the Cochrane Central Register were searched for randomized trials from January 1990 to December 2014 comparing AF catheter ablation to drug therapy. The results are reported as risk differences （RDs） and 95% CI. Thirteen trials were analyzed with 1097 patients treated by catheter ablation and 855 patients received antiarrhythmic drug therapy. Overall, seven patients （0.64%） in the catheter ablation group had ischemic stroke or transient ischemic attacks vs. two patients （0.23%） in the drug therapy group. No difference was shown in the rate of stroke or transient ischemic attack between ablation and drug therapy （RD： 0.003, 95% CI： -0.006 to 0.012, P = 0.470）, and no evidence of heterogeneity was observed （I^2 = 0, P = 0.981）. No potential publication bias was found. There was also no difference in mortality between the two groups （RD： -0.004, 95% CI： -0.014 to 0.006, P = 0.472）. Conclusions This meta-analysis of randomized controlled trials showed similar rates of ischemic stroke or transient ischemic attack and death in AF patients undergoing catheter ablation compared to drug therapy. A larger prospective randomized trial to confirm this finding is warranted.

Reversal of pulmonary vein remodeling after catheter ablation of atrial fibrillation

Background Pulmonary veins （PV） and the atria undergo electrical and structural remodeling in atrial fibrillation （AF）. This study aimed to determine PV and left atrial （LA） reverse remodeling after catheter ablation for AF assessed by chest computed tomography （CT）. Methods PV electrophysiologic studies and catheter ablation were performed in 63 patients （68% male; mean ± SD age： 56 ± 10 years） with symptomatic AF （49% paroxysmal, 51% persistent）. Chest CT was performed before and 3 months after catheter ablation. Results At baseline, patients with persistent AF had a greater LA volume （91 ±29 cm3 vs. 66 ± 27 cm3; P = 0.003） and mean PV ostial area （241 ＋ 43 mm2 vs. 212 ± 47 mm2; P = 0.03） than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients （76%） were AF free on or off antiarrhythmic drugs. There was a significant reduction in LA volume （77 ±31 cm3 to 70 ± 28 cm3; P 〈 0.001） and mean PV ostial area （224 ± 48 mm2 to 182 ± 43 mm2; P 〈 0.001）. Patients with persistent AF had more reduction in LA volume （11.8 ± 12.8 cm3 vs. 4.0 ± 11.2 cm3; P = 0.04） and PV ostial area （62 mm2 vs. 34 mm2; P = 0.04） than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume （r = 0.38, P = 0.03）. Conclusions Catheter ablation of AF improves structural remodeling ofPV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.

Successful Anesthetic Management for Surgical Repair of Atrio-Esophageal Fistula Following Radiofrequency Ablation for Atrial Fibrillation

Introduction: Atrio-esophageal fistula is a rare but often fatal complication of radiofrequency ablation for atrial fibrillation. Here we report a successful case in anesthetic management of surgical repair of atrio-esophageal fistula. Case Report: The patient was a 56-year-old man status post radiofrequency ablation for atrial fibrillation one month before presenting with fever and symptoms and signs of cerebral emboli. He was diagnosed as having atrio-esophageal fistula, which required emergent surgical repair. In the operating room, rapid sequence induction was performed with avoidance of positive pressure ventilation before securing airway. Double lumen tube was used for lung isolation for left thoracotomy. Upon exploration, a small fistula was identified. Both atrial and esophageal defects were ligated and an intercostal muscle flap was placed. The patient’s heart rhythm was atrial flutter/atrial fibrillation with marginal hemodynamics during the procedure, but cardioversion was delayed until the fistula was repaired and no remaining air, blood clot or gastric content in the heart was confirmed by epicardial ultrasound. The patient tolerated the surgery and was transferred to ICU, intubated and ventilated. He recovered from surgery and was transferred to a rehabilitation hospital with residual expressive aphasia. Conclusion: We had a successful case in anesthetic management for surgical repair of atrio-esophageal fistula by preventing massive bleeding as well as multiple air embolization through the fistula.

Design and Baseline Patient Characteristics of the Prospective, Observational, Multicenter and Multinational Cohort Study Comparing Radiofrequency with Cryoablation for Pulmonary Vein Isolation in Patients with Atrial Fibrillation—The Freeze Cohort Study

Aims: The FREEZE-cohort study (NCT 01360008) is a prospective observational, multicenter and multinational study to evaluate safety and effectiveness of cryoballoon ablation for pulmonary vein isolation as compared to radiofrequency ablation in patients with paroxysmal or persistent atrial fibrillation (lasting < one year) under the conditions of clinical routine. Methods and Results: The study started in 2011 and anticipates inclusion up to 2000 patients in each of the two treatment groups. A total of 37 centers from 8 countries worldwide, all experienced in at least one of the two ablation techniques, participate in the study. The primary outcome parameter of the study is defined as atrial fibrillation recurrence rate during twelve months of follow-up. Secondary outcome parameters include primary success rates, complication rates in general, specific complications with respect to phrenic nerve palsy and pulmonary vein stenosis, radiation exposure, clinical course including death and repeat ablation. Finally specific procedural aspects will be evaluated in a descriptive manner. Preliminary data of the first 1882 patients show that in clinical practice cryoablation is preferentially performed in patients with paroxysmal atrial fibrillation, whereas application of radiofrequency ablation is equally distributed between patients with persistent and paroxysmal atrial fibrillation. Conclusion: Based on multi-center and multi-national data the FREEZE-cohort study will provide important information on long-term efficacy, clinical effectiveness, complication rates and procedural differences between atrial fibrillation patients treated with either cryoablation or radiofrequency ablation.

Clinical utility of left atrial strain in predicting atrial fibrillation recurrence after catheter ablation: An up-to-date review

Rhythm control is the core part of the integrated management of atrial fibrillation(AF),especially in the early stages.Despite advances in catheter ablation(CA),the recurrence rate of AF after CA remains high.As a result,stratification and early management of AF recurrence after CA are critical.Currently,predictors of recurrence of AF after CA are mostly based on dysfunction caused by structural remodeling,apart from traditional risk factors.Atrial strain is a recently developed important parameter for detecting the deformability of atrial myocardium during the cardiac cycle prior to atrial remodeling.Although there is only preliminary evidence,atrial strain is still a promising parameter in predicting the recurrence of AF after CA at an early stage.This review focuses on the evaluation of atrial strain,the current applications of atrial strain in assessing atrial function,and predicting the recurrence of AF after CA.We summarize the contents related as follows:(1)CA for rhythm control in AF;(2)Evaluation methods of atrial strain;(3)Atrial strain in the remodeling and reverse remodeling of AF;and(4)Clinical applications of atrial strain in predicting the recurrence of AF after CA.Although there is accumulating evidence on the role of decreased atrial strain in the early prediction of AF recurrence,atrial strain is limited in clinical practice for lacking exact cut-off values and difficulty in distinguishing specific function phases of the atrium.More research is needed in the future to add strength to the early prediction value of atrial strain in AF recurrences.

Left atrial voltage remodeling after pulmonary venous isolation with multipolar radiofrequency ablation

Purpose: Pulmonary vein isolation (PVI) is the accepted primary endpoint for catheter ablation of atrial fibrillation (AF). The aim of this study was to evaluate the level of PVI by PVAC, a multipolar circular catheter utilizing bipolar/unipolar radiofrequency (RF) energy. Methods: Twenty patients with paroxysmal AF underwent PVAC ablation. PVI was validated by voltage reduction and pacing tests. Before and after RF ablation, left atrium (LA) and PV electroanatomic mapping (EAM) were performed by EnSite NavX system. Voltage abatement was considered for potentials 24mm: 9/20 (45%) vs 11/57 (19%),