Second-generation cryoballoon ablation for treatment of persistent atrial fibrillation: Three-year outcome and predictors of recurrence after a single procedure

Cryoballoon Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: From the Korean Cryoballoon Ablation Registry

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) occurs in more than 20% of hypertrophic cardiomyopathy (HCM) patients, further increasing the risk of stroke. Although radiofrequency catheter ablation in AF patients with HCM has been performed, data on cryoballoon ablation (CBA) in HCM patients are limited. We evaluated the efficacy and safety of CBA in HCM patients with AF.

METHODS

The study included 2,649 patients with AF from the Korean CBA registry database with follow-up >12 months after de novo CBA. The primary efficacy outcome was recurrence of atrial tachyarrhythmias (ATs) ≥30s after a 3-month blanking period.

RESULTS

Totals of 1,176 paroxysmal AF (44.4%) and 1,473 persistent atrial fibrillation (PeAF, 55.6%) patients (mean age 61.7 years; 76.7% men) underwent de novo CBA. Compared to non-HCM patients (n=2,590), those with HCM (n=59) had larger left atrium and higher prevalence of heart failure, previous stroke or transient ischemic attack, and PeAF. Procedure-related complications were not statistically different between the 2 groups. During a mean follow-up period of 638±308 days, 875 (33.0%) patients experienced recurrence of ATs (845 [32.6%] non-HCM patients and 30 [50.8%] HCM patients) (p=0.01). The overall AT-free survival rate at 2 years was 45.9% in HCM group and 63.3% in non-HCM group, respectively (p=0.014), whereas there was no significant difference between the two groups in PeAF.

CONCLUSIONS

CBA may be an effective rhythm control treatment for patients with AF and HCM, with an AT-free survival rate of approximately 50% at 2-year follow-up and low procedure-related complications.

Intracardiac echocardiography Chinese expert consensus

In recent years, percutaneous catheter interventions have continuously evolved, becoming an essential strategy for interventional diagnosis and treatment of many structural heart diseases and arrhythmias. Along with the increasing complexity of cardiac interventions comes ever more complex demands for intraoperative imaging. Intracardiac echocardiography (ICE) is well-suited for these requirements with real-time imaging, real-time monitoring for intraoperative complications, and a well-tolerated procedure. As a result, ICE is increasingly used many types of cardiac interventions. Given the lack of relevant guidelines at home and abroad and to promote and standardize the clinical applications of ICE, the members of this panel extensively evaluated relevant research findings, and they developed this consensus document after discussions and correlation with front-line clinical work experience, aiming to provide guidance for clinicians and to further improve interventional cardiovascular diagnosis and treatment procedures.

The Long-Term Outcomes of Ablation With Vein of Marshall Ethanol Infusion vs. Ablation Alone in Patients With Atrial Fibrillation: A Meta-Analysis

Background

The long-term outcomes of ablation with vein of Marshall ethanol infusion (VOM-ABL) compared with ablation alone in patients with atrial fibrillation (AF) remains elusive. We aimed to explore whether VOM-ABL showed better long-term benefits and screen the potential determinants of outcome impact of VOM-ABL procedure.

Methods

PubMed, Cochrane Library, Web of Science, and Embase were searched up to 1st September 2021. Studies comparing the long-term (one-year or longer) outcomes between VOM-ABL and ablation alone were included. Subgroup analysis identified potential determinants for VOM-ABL procedure.

Results

Compared with ablation alone, VOM-ABL was associated with a significantly higher rate of long-term freedom from AF/AT (risk ratio [RR], 1.28; 95% confidence interval [CI], 1.12–1.47; p = 0.00) and successful mitral isthmus (MI) block (RR, 1.52; 95% CI, 1.16–1.99; p = 0.00), whereas, there was no significant difference in pericardial effusion, stroke/transient ischemic attack (TIA), and all-cause death. Subgroup analysis identified two significant treatment-covariate interactions: one was ablation strategy subgroup (pulmonary vein isolation plus linear and/or substrate ablation [PVI+]; RR, 1.41; 95% CI, 1.27–1.56 vs. PVI; RR, 1.05; 95% CI, 0.92–1.19, p = 0.00 for interaction) for freedom from AF/AT, while the other was VOM-ABL group sample size subgroup (≥ 100; RR, 1.98; 95% CI, 1.24–3.17 vs. <100; RR, 1.20; 95% CI, 1.10–1.30, p = 0.04 for interaction) for MI block.

Conclusions

This meta-analysis demonstrates that VOM-ABL has superior efficacy and comparable safety over ablation alone in AF patients with long-term follow-up. Moreover, PVI+ and VOM-ABL group sample size ≥ 100 may be associated with a great impact on freedom from AF/AT and MI block, respectively.

Improving the Quality of Human Upper Urinary Tract Specimens by Cryobiopsy

Objective

The quality of histopathological specimens obtained from the upper urinary tract with conventional flexible ureterorenoscopic biopsy needs to be improved. We investigated the feasibility and biopsy quality of specimens obtained by cryobiopsy, compared with standard ureterorenoscopic biopsy techniques in a human ex vivo model.

Materials and Methods

Human ureters obtained from nephrectomy specimens (N=12) were dissected and canulated with an ureteral access sheath. Ureterorenoscopic biopsies were randomly obtained from different sites of the renal pelvic caliceal system using different types of instruments. The performance of two newly developed flexible cryoprobes with outer diameters of 1.1 mm (CB11) and 0.9 mm (CB09) was compared with that of the biopsy forceps(FB) and Bigopsy®(BiG) and two different Dormia baskets N‐Gage (NG) and Zero‐Tip (ZT). We assessed the feasibility of the various biopsy techniques based on the number of biopsy attempts needed to obtain macroscopically discernible biopsies. The specimens were examined histopathologically for size, biopsy quality, presence of various artifact types, and representativeness.

Results

Biopsies taken with the cryoprobes showed a higher biopsy quality than biopsies taken with the comparative instruments. The CB11 provided significantly larger biopsies than forceps biopsies and also than biopsies with ZT. The CB09 was able to collect larger samples when compared with the FB and BiG biopsy forceps. There were no significant differences in artifact area, except for the CB11 cryoprobe compared with the NG. To clarify the results a subdivision of larger or smaller than 20% artifact area was performed. A significant difference was found between CB11 and the forceps biopsies, as well as between CB11 and NG and ZT in favor of the cryoprobe. The representation of the histopathological sample was also determined. Biopsies taken with CB11 were more representative compared with forceps biopsies BiG and FB and basket biopsies NG and ZT.

Conclusions

In a standardized comparative ex vivo setting, larger biopsies were obtained by using the cryobiopsy technique with the CB11 probe. Qualitatively, cryobiopsy specimens were overlaid by fewer artifacts and a higher biopsy quality was achieved in histopathologic examination compared with standard instrumentation. Further stepwise development will transfer the promising cryobiopsy technique into the clinical setting.

Ablation Therapy for Persistent Atrial Fibrillation

Atrial Fibrillation (AF) is the most common form of electrical disturbance of the heart and contributes to significant patient morbidity and mortality. With a better understanding of the mechanisms of atrial fibrillation and improvements in mapping and ablation technologies, ablation has become a preferred therapy for patients with symptomatic AF. Pulmonary Vein Isolation (PVI) is the cornerstone for AF ablation therapy, but particularly in patients with AF occurring for longer than 7 days (persistent AF), identifying clinically significant nonpulmonary vein targets and achieving durability of ablation lesions remains an important challenge.

Cryoballoon Ablation Strategy in Persistent Atrial Fibrillation

Background: Cryoballoon ablation is established for pulmonary vein isolation (PVI) in paroxysmal atrial fibrillation (AF). The objective was to evaluate CBA strategy in consecutive patients with persistent AF in the initial AF ablation procedure.

Material and Methods: Prospectively, patients with symptomatic persistent AF scheduled for AF ablation all underwent cryoballoon PVI. Technical enhancements, laboratory management, safety, single-procedure outcome, predictors of recurrence, and durability of PVI were evaluated.

Results: From 2007 to 2020, a total of 1,140 patients with persistent AF, median age 68 years, underwent cryoballoon ablation (CBA). Median left atrial (LA) diameter was 45 mm (interquantile range, IQR, 8), and Congestive heart failure, Hypertension, Age ≥75 years (doubled), Diabetes mellitus, prior Stroke or TIA or thromboembolism (doubled), Vascular disease, Age 65 to 74 years, Sex category (CHA₂DS₂-VASc) score was 3. Acute isolation was achieved in 99.6% of the pulmonary veins by CBA. Median LA time and median dose area product decreased significantly over time (p < 0.001). Major complications occurred in 17 (1.5%) patients including 2 (0.2%) stroke/transitory ischemic attack (TIA), 1 (0.1%) tamponade, relevant groin complications, 1 (0.1%) significant ASD, and 4 (0.4%) persistent phrenic nerve palsy (PNP). Transient PNP occurred in 66 (5.5%) patients. No atrio-esophageal fistula was documented. Five deaths (0.4%), unrelated to the procedure, occurred very late during follow-up. After initial CBA, arrhythmia recurrences occurred in 46.6% of the patients. Freedom from atrial arrhythmias at 1-, and 2-year was 81.8 and 61.7%, respectively. Independent predictors of recurrence were LA diameter, female sex, and use of the first cryoballoon generation. Repeat ablations due to recurrences were performed in 268 (23.5%) of the 1,140 patients. No pulmonary vein (PV) reconduction was found in 49.6% of the patients and 73.5% of PVs. This rate increased to 66.4% of the patients and 88% of PVs if an advanced cryoballoon was used in the first AF ablation procedure.

Conclusion: Cryoballoon ablation for symptomatic persistent AF is a reasonable strategy in the initial AF ablation procedure.

Results and Predictive Factors After One Cryoablation for Persistent Atrial Fibrillation

Cryoballoon pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) ablation is an increasingly used strategy. We aimed to determine the results and predictors of arrhythmia recurrence after a single procedure of cryoballoon PVI for patients with persistent and long-standing persistent AF. We included all consecutive patients who underwent cryoballoon PVI for the treatment of persistent symptomatic drug-refractory AF since 2012. All patients were prospectively followed to detect the recurrence of atrial tachyarrhythmia (ATa). Predictors of recurrence were assessed. Cryoballoon PVI was performed on 399 patients with persistent AF, among whom 52 (13%) had long-standing persistent AF. Patients with long-standing persistent AF had a significantly larger left atrium than those with persistent AF. A 28-mm cryoballoon was used for 322 patients (93%). In total, 359 patients (90%) completed the 12-month follow-up visit and the median follow-up was 24 months (interquartile range 43 to 13). The 2-year probability of freedom from ATa recurrence was 51% for persistent AF and 27% for long-standing persistent AF. Long-standing persistent AF and left atrial area/volume were independent predictors of ATa recurrence. Ten patients (2.5%) experienced phrenic nerve palsy, 1 tamponade (0.25%), 2 stroke (0.5%), 2 pericardial effusions (0.5%), and 5 vascular complications (1.25%). In conclusion, 2-year ATa-free survival rates were 51 and 27% for persistent and long-standing persistent AF patients, respectively. Complications were rare. Long-standing persistent AF and left-atrial area/volume were predictors of recurrence.

Anatomical targets and expected outcomes of catheter-based ablation of atrial fibrillation in 2020

Anatomical-based approaches, targeting either pulmonary vein isolation (PVI) or additional extra PV regions, represent the most commonly used ablation treatments in symptomatic patients with atrial fibrillation (AF) recurrences despite antiarrhythmic drug therapy. PVI remains the main anatomical target during catheter-based AF ablation, with the aid of new technological advances as contact force monitoring to increase safety and effective radiofrequency (RF) lesions. Nowadays, cryoballoon ablation has also achieved the same level of scientific evidence in patients with paroxysmal AF undergoing PVI. In parallel, electrical isolation of extra PV targets has progressively increased, which is associated with a steady increase in complex cases undergoing ablation. Several atrial regions as the left atrial posterior wall, the vein of Marshall, the left atrial appendage, or the coronary sinus have been described in different series as locations potentially involved in AF initiation and maintenance. Targeting these regions may be challenging using conventional point-by-point RF delivery, which has opened new opportunities for coadjuvant alternatives as balloon ablation or selective ethanol injection. Although more extensive ablation may increase intraprocedural AF termination and freedom from arrhythmias during the follow-up, some of the targets to achieve such outcomes are not exempt of potential severe complications. Here, we review and discuss current anatomical approaches and the main ablation technologies to target atrial regions associated with AF initiation and maintenance.

Magnetic resonance imaging-guided cryoballoon ablation for left atrial substrate modification in patients with atrial fibrillation

BACKGROUND

Cryoballoon ablation (CBA) for pulmonary vein isolation (PVI) is an established modality for the treatment of atrial fibrillation (AF). We report feasibility of left atrial (LA) substrate modification in addition to PVI both using the cryoballoon.

METHODS

LA substrates and CBA-induced scar were assessed at baseline and 3 months after ablation using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). Common periprocedural data including postablation LGE-MRI for evaluation of esophageal thermal injury, and CBA-associated complications were collected. Freedom from AF recurrence at 12 months was assessed using Holter and 30-day rhythm monitors.

RESULTS

In 26 patients (64 ± 11 years, 69% male; 27% persistent AF, CHADSVASC score: 2.3 ± 1.5; left ventricular ejection fraction: 56 ± 10%, oral anticoagulation with warfarin/direct oral anticoagulants: n = 11/15), referred for first-time AF ablation, CBA of the pulmonary veins and extrapulmonary LA substrates was performed (median: 12 [interquartile range {IQR}: 7-14] freezes over 1675 seconds [IQR: 1168-2160]). On LGE-MRI, significant postablation cryoballoon-induced LA scar (median: 19.4% [IQR: 13.4-24.7] in comparison to baseline preablation LA-LGE (median: 10.6% [IQR 3.1-13.1]; P = .01) was found. Freedom from AF recurrence at 12 months was 74.5% with median time-to-recurrence of 242 days (IQR: 172-298). In 15 of 26 (58%) patients, esophageal enhancement on the postablation MRI was present with full recovery after 3 months. No major periprocedural complications were observed.

CONCLUSION

LA substrate modification in addition to PVI using LGE-MRI-guided CBA is feasible but still experimental. The efficacy and safety have to be investigated in a prospective randomized trial.

Strategies to Improve the Outcome of Cryoballoon Ablation in the Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is a common arrhythmia contributing to severe outcomes, including cardiac dysfunction and stroke, and it has drawn great attention around the world. Drug therapies have been available for many years to terminate AF and control heart rate. However, the results from clinical studies on drug therapies have been discouraging. Mounting evidence indicates that radiofrequency catheter ablation (RFCA) is a safe and effective method to maintain sinus rhythm, especially in patients who are drug intolerant or for whom the drugs are ineffective, although it is a technically demanding and complex procedure. Fortunately, a novel application, cryoballoon ablation (CBA), with outstanding characteristics has been widely used. Great outcomes based on CBA have manifested its significant role in the treatment of AF. However, how to improve the safety and efficacy of CBA is a question that has not been well-answered. Would it be helpful to develop a different generation of cryoballoon? Is bonus freezing beneficial, or not? Is it better to prolong freezing time? Dose CBA combined with RFCA bring higher success rates? In this review, we comprehensively summarized useful applications for improving outcomes of CBA in AF patients.

Conversion of atrial fibrillation to sinus rhythm during cryoballoon ablation: A favorable and not unusual phenomenon during second-generation cryoballoon pulmonary vein isolation

BACKGROUND

The prevalence and the clinical impact of conversion of atrial fibrillation (AF) to sinus rhythm (SR) during cryoballoon ablation (CB-A) are unknown.

OBJECTIVE

The purpose of this study was to evaluate the prevalence of restoration of SR during CB-A and the clinical impact of this phenomenon.

METHODS

Between January 2012 and September 2018, all patients who experienced conversion of AF to SR during CB-A were included. This group was subsequently matched for gender, age, type of AF, diagnosis-to-ablation time, and left atrial size with patients who underwent CB-A and did not experienced conversion of AF to SR. After discharge, patients were scheduled for follow-up visits at 1, 3, 6, and 12 months and 24 hours Holter recordings were obtained at each follow-up visit. All documented AF episodes of >30 seconds were considered as recurrence. A 3 month post-procedural blanking period (BP) was applied.

RESULTS

A total of 1559 patients underwent pulmonary veins isolation by CB-A between January 2012 and September 2018; among them, 58 patients (3.7%) experienced restoration of SR during CB-A. In total, 53 patients (41 males [77.3%], mean age 61.4 ± 13.3 years) were included in the case group. During CB-A, restoration of SR occurred more frequently during right-side PVs applications (right inferior pulmonary vein 39.6%, right superior pulmonary vein 30.2%). If considering a BP, at 2 year follow-up, freedom from recurrences was 86.5% in the case group and 68.0% in the control group (P = .036).

CONCLUSION

Conversion of AF to SR is a favorable and relatively frequent phenomenon during cryoballoon pulmonary vein isolation ablation.

Medium- and long-term outcome after a single second-generation cryoballoon ablation in patients with paroxysmal and persistent atrial fibrillation

INTRODUCTION AND OBJECTIVES

To report medium- and long-term results following a single second-generation cryoballoon (CB2)-based ablation procedure in patients with paroxysmal (PAF) and persistent (PeAF) atrial fibrillation.

METHODS

A retrospective study was performed of consecutive patients undergoing a first CB2-based ablation procedure in a tertiary center. Cryoenergy was applied for 3 min if a time to effect <60 s was documented or 4 min otherwise, with a bonus application in cases of late isolation or suboptimal temperature. Follow-up was obtained from the regional health electronic records system and by telephone or personal interviews. Recurrence was defined as any atrial arrhythmia >30 s beyond a three-month blanking period. The clinical impact of recurrences was classified using a severity score.

RESULTS

A total of 172 patients (134 PAF and 38 PeAF) were included, of whom 25 (14.5%) had structural heart disease and 120 (69.7%) had a normal or mildly dilated left atrium. Acute success was achieved in 167 (97.1%). After a median follow-up of 27 (14-41) months, 100 patients (58.1%) remained free of atrial arrhythmias (64.2% for PAF and 36.8% for PeAF, p=0.006). Left atrial size (p=0.05) and clinical presentation as PeAF (p=0.006) were predictors of recurrence. Of patients with recurrences, 11.1% did not require further therapies and an additional 16.7% had good control with antiarrhythmic drugs.

CONCLUSIONS

A single CB2 procedure resulted in 58.1% of patients remaining free of atrial arrhythmias at 27-month follow-up. Conservative management was useful in 27.8% of patients with recurrences.

Comparison of Outcomes Using the First and Second Generation Cryoballoon to Treat Atrial Fibrillation

BACKGROUND

Pulmonary vein isolation using cryoballoon ablation is an effective treatment for patients with atrial fibrillation. We sought to compare outcomes with the first and second generation cryoballoon, with the second generation balloon incorporating the Achieve Lasso catheter, in terms of freedom from symptomatic recurrence and major complications.

METHODS

The first 200 patients who underwent cryoballoon ablation with the first generation balloon were compared with the first 200 patients using the second-generation balloon. All patients had symptomatic atrial fibrillation and had failed at least one antiarrhythmic drug. The primary efficacy endpoint was freedom from symptomatic recurrence of atrial fibrillation (AF) after a single pulmonary vein isolation (PVI) procedure using the cryoballoon. The primary safety endpoint was major procedural complications.

RESULTS

At 12 months, freedom from symptomatic AF after a single procedure in the first generation cohort was 64.3% compared with 78.6% in the second-generation cohort (p = 0.002). At 24 months, freedom from symptomatic AF in the first generation cohort was 51.3% compared with 72.6% in the second-generation cohort (p < 0.001). Procedural time (150 min vs 101 min; p < 0.001) and fluoroscopy time (32.5 min vs 21.4 min; p < 0.001) was lower in the second-generation group. The rate of major complications was comparably low in both groups.

CONCLUSIONS

The second-generation cryoballoon was associated with improved freedom from symptomatic AF with reduction in procedure and fluoroscopy time, with a similar low rate of major complications.

Patient characteristics as predictors of recurrence of atrial fibrillation following cryoballoon ablation

BACKGROUND

While several studies have evaluated predictors for atrial fibrillation (AF) recurrence following catheter ablation, there are limited data specific to cryoballoon ablation (CBA).

METHODS

We analyzed a prospective registry of patients at a single institution who underwent CBA. Recurrence of AF (RAF) was defined as recurrence of AF by 12-month follow-up, excluding the 3-month blanking period. Univariate analysis was performed to evaluate predictors of RAF. Receiver operating characteristic analysis was used to compare and evaluate the performance of various risk scores for discriminating risk of RAF.

RESULTS

There were 542 patients included in the analysis with mean age 61.3 ± 10.6 years, 67.9% male, and 51.6% paroxysmal AF (PAF). Overall, only left atrial diameter (LAD) > 40 mm and ERAF (early recurrence of AF within 0-3 month blanking period) were significant predictors of RAF. In the PAF specific subgroup, LAD > 40 mm, AF duration > 12 months, prior stroke or transient ischemic attack, ERAF, and having previously failed an antiarrhythmic drug were significant predictors of RAF. In persistent AF (PeAF) subgroup, obstructive sleep apnea (OSA) and ERAF were significant predictors of RAF. Out of clinical risk scores tested, BASEAF2 had the highest performance with area under the curve of 0.646 (95% confidence interval [0.548, 0.708]; P < .01).

CONCLUSIONS

In this single-center retrospective study of CBA, we found only LAD > 40 mm and ERAF to be predictors of RAF. We identified OSA as a potential targetable risk factor in PeAF patients undergoing CBA. Out of risk scores tested for discriminating risk of RAF, BASEAF2 had the best performance.

Clinical outcome of the 2nd generation cryoballoon for pulmonary vein isolation in patients with persistent atrial fibrillation - A sub-study of the randomized trial evaluating single versus dual cryoballoon applications

AIMS

To assess the efficacy of the 2nd generation Cryoballoon for pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (PersAF), and to compare it to patients with paroxysmal atrial fibrillation (PAF).

METHODS

The outcome (arrhythmia recurrence at 12 months) was prospectively assessed in patients with PersAF(n = 77) and compared to that in patients with PAF(n = 62), who underwent PVI within a randomized trial evaluating single versus dual applications with the 2nd generation cryoballoon. Other endpoints included symptoms of AF, quality of life, procedure related characteristics, redo ablation rates and adverse events. Variables predicting recurrences were studied including all patients.

RESULTS

Freedom from arrhythmia recurrence was 64.9% after a single ablation and 68.8% after one or more procedures, which was significantly lower compared to PAF patients; 82.2% (p = 0.029) and 83.9% (p = 0.048) respectively, at 12 months. The improvements in EHRA score (-1.3 ± 0.8, p < 0.0001), symptom severity score (SSQ) (-5.0 ± 4.2, p < 0.0001) and EQ5D-5 L global score (+10.4 ± 20.3, p = 0.0002) after ablation was significant compared to baseline. The re-ablation rate was 7/77 (9.1%) which did not differ from that in PAF patients, 9/62 (14.5%), p = 0.42. Procedure duration, 104.8 ± 37.4 versus 113 ± 31.2 min (p = 0.129), application time, 1605 ± 659 versus 1521 ± 557 s (p = 0.103) and total adverse events after 12 months, 8/77 (10.4%) versus 5/62 (8.1%) (p = 0.77) did not differ in PersAF versus PAF patients.

CONCLUSION

Both symptoms and QoL improved significantly in patients with PersAF after ablation. Freedom from AF was clinically significant but lower than in PAF patients. The cryoballoon seems an effective technique also in patients with persistent AF.

The safety and efficacy of second-generation cryoballoon ablation plus catheter ablation for persistent atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Growing evidence suggests that second-generation cryoballoon ablation (2G-CB) is effective in patients with persistent atrial fibrillation (PerAF). The cornerstone of atrial fibrillation (AF) ablation is pulmonary vein isolation (PVI). The purpose of this study was to summarize the available data on the safety and mid-term (≥ 12 months) effectiveness of a 'PVI-only' strategy vs. a 'PVI-plus' strategy using 2G-CB in patients with PerAF.

METHODS

We searched the PubMed, EMBASE and Cochrane library databases for studies on 2G-CB for PerAF. Group analysis was based on the ablation approach: 'PVI-only' versus 'PVI-plus', the latter of which involved PVI plus other substrate modifications. Studies showing clinical success rates at a follow-up (FU) of ≥ 12 months were included. Complication rates were also assessed. Data were analyzed by applying a fixed effects model.

RESULTS

A total of 879 patients from 5 studies were analyzed. After a mid-term FU of 27 months, the overall success rate of 2G-CB for PerAF was 66.1%. In the 'PVI-plus' group, the success rate was 73.8%. In the 'PVI-only' group, the success rate was 53.6%. No heterogeneity was noted among studies (I2 = 0.0%, P = 0.82). Complications occurred in 5.2% of patients (P = 0.93), and the rate of phrenic nerve (PN) injury was 2.8% (P = 0.14). Vascular assess complications were the most frequent at 1.6% (P = 0.33). No death or myocardial infarction was reported.

CONCLUSION

'PVI-plus' involving 2G-CB seems to be safe and effective for treating PerAF.

Atrial fibrillation ablation using cryoballoon technology: Recent advances and practical techniques

Atrial fibrillation (AF) affects 1-2% of the population, and its prevalence is estimated to double in the next 50 years as the population ages. AF results in impaired patients' life quality, deteriorated cardiac function, and even increased mortality. Antiarrhythmic drugs frequently fail to restore sinus rhythm. Catheter ablation is a valuable treatment approach for AF, even as a first-line therapy strategy in selected patients. Effective electrical pulmonary vein isolation (PVI) is the cornerstone of all AF ablation strategies. Use of radiofrequency (RF) catheter in combination of a three-dimensional electroanatomical mapping system is the most established ablation approach. However, catheter ablation of AF is challenging even sometimes for experienced operators. To facilitate catheter ablation of AF without compromising the durability of the pulmonary vein isolation, "single shot" ablation devices have been developed; of them, cryoballoon ablation, is by far the most widely investigated. In this report, we review the current knowledge of AF and discuss the recent evidence in catheter ablation of AF, particularly cryoballoon ablation. Moreover, we review relevant data from the literature as well as our own experience and summarize the key procedural practical techniques in PVI using cryoballoon technology, aiming to shorten the learning curve of the ablation technique and to contribute further to reduction of the disease burden.

Practical Techniques in Cryoballoon Ablation: How to Isolate Inferior Pulmonary Veins

Catheter ablation is the most effective treatment option for patients suffering from symptomatic atrial fibrillation. Electrical isolation of the pulmonary veins is the procedural cornerstone. Point-by-point radiofrequency current energy ablation in combination with a 3D electro-anatomical mapping system is the established approach to ablation. In contrast, cryoballoon ablation uses a single-shot approach to facilitate pulmonary vein isolation. However, fixed cryoballoon diameters (28 mm or 23 mm) and non-balloon compliance can lead to technical difficulties in isolating variable pulmonary vein anatomies. This review focuses on key procedural aspects and illustrates practical techniques in cryoballoon pulmonary vein isolation to shorten the learning curve without compromising safety and efficacy. It has a special emphasis on inferior pulmonary veins.