Comparison of the First and Second Cryoballoon

Safety of pulsed field ablation in more than 17,000 patients with atrial fibrillation in the MANIFEST-17K study

Pulsed field ablation (PFA) is an emerging technology for the treatment of atrial fibrillation (AF), for which pre-clinical and early-stage clinical data are suggestive of some degree of preferentiality to myocardial tissue ablation without damage to adjacent structures. Here in the MANIFEST-17K study we assessed the safety of PFA by studying the post-approval use of this treatment modality. Of the 116 centers performing post-approval PFA with a pentaspline catheter, data were received from 106 centers (91.4% participation) regarding 17,642 patients undergoing PFA (mean age 64, 34.7% female, 57.8% paroxysmal AF and 35.2% persistent AF). No esophageal complications, pulmonary vein stenosis or persistent phrenic palsy was reported (transient palsy was reported in 0.06% of patients; 11 of 17,642). Major complications, reported for ~1% of patients (173 of 17,642), were pericardial tamponade (0.36%; 63 of 17,642) and vascular events (0.30%; 53 of 17,642). Stroke was rare (0.12%; 22 of 17,642) and death was even rarer (0.03%; 5 of 17,642). Unexpected complications of PFA were coronary arterial spasm in 0.14% of patients (25 of 17,642) and hemolysis-related acute renal failure necessitating hemodialysis in 0.03% of patients (5 of 17,642). Taken together, these data indicate that PFA demonstrates a favorable safety profile by avoiding much of the collateral damage seen with conventional thermal ablation. PFA has the potential to be transformative for the management of patients with AF.

Comparison of Second-Generation Cryoballoon Ablation and Quantitative Radiofrequency Ablation Guided by Ablation Index for Atrial Fibrillation

We compared the efficacy and complication rates of quantitative radiofrequency ablation guided by ablation index (RFCA-AI) with those of second-generation cryoballoon ablation (CBA-2). Consecutive patients (n = 230) with symptomatic atrial fibrillation (AF) undergoing a first ablation CBA-2 (92 patients) or RFCA-AI (138 patients) procedure were enrolled in this study. The late recurrence rate in the CBA-2 group was higher than that in the RFCA-AI group (P = .012). Subgroup analysis showed the same result in patients with paroxysmal AF (PAF) (P = .039), but no difference was found in patients with persistent AF (P = .21). The average operation duration in the CBA-2 group (85 [75-99.5] minutes) was shorter than that in the RFCA-AI group (100 [84.5-120] minutes) (P < .0001), but the average exposure time (17.36(13.87-22.49) vs 5.49(4.00-8.24) minutes) in the CBA-2 group and X-ray dose (223.25(149.15-336.95) vs 109.15(80.75-168.7) mGym) were significantly longer than those in RFCA-AI group (P < .0001). Multivariate logistic regression analysis showed that left atrial diameter (LAD), early recurrence, and methods of ablation (cryoballoon ablation) were independent risk factors for late recurrence after AF ablation. Early recurrence of AF and LAD were independent risk factors for predicting late recurrence after AF ablation.

A randomized controlled trial of the size-adjustable cryoballoon vs conventional cryoballoon for paroxysmal atrial fibrillation: The CONTRAST-CRYO II trial rationale and design

Background

Pulmonary vein isolation (PVI) with cryoballoon technology is a well-established therapy for treatment of atrial fibrillation (AF). Recently, a size-adjustable cryoballoon (POLARxTM FIT) that enables delivery in a standard 28-mm or an expanded 31-mm size was introduced.

Objective

The purpose of this study was to perform a randomized clinical trial to evaluate the safety and efficacy of this novel cryoballoon compared to the conventional cryoballoon.

Methods

The CONTRAST-CRYO II trial is a multicenter, prospective, open-label, randomized controlled trial in which 214 patients with paroxysmal AF will be randomized 1:1 to cryoballoon ablation with either a conventional cryoballoon (Arctic Front AdvanceTM Pro) or a size-adjustable cryoballoon (POLARx FIT). The study was approved by the Institutional Review Boards at all investigational sites and has been registered in the UMIN Clinical Trials Registry (UMIN000052500).

Results

The primary endpoint of this study will be the incidence of phrenic nerve injury. Secondary endpoints include procedural success, chronic success through 12 months, procedure-related adverse events, biophysiological parameters during applications for each pulmonary vein (PV), total procedural and fluoroscopy times, level of PVI and isolation area, and probability of non-PV foci initiating AF.

Conclusion

The CONTRAST-CRYO II trial is a multicenter, prospective, randomized controlled trial designed to assess the safety and efficacy of the POLARx FIT vs the Arctic Front Advance Pro. The findings from this trial will provide additional utility data on the efficacy of the size-adjustable cryoballoon for isolating PVs in patients with paroxysmal AF.

Impact of intracardiac echocardiography usage on the safety of cryoballoon atrial fibrillation ablation: Subanalysis of the prospective FREEZE cluster cohort study

INTRODUCTION

Cryoballoon ablation (CBA) aiming at pulmonary vein isolation (PVI) became a standardized atrial fibrillation (AF) ablation procedure. Life-threatening complications like cardiac tamponade exist. Intracardiac echocardiography (ICE) usage is associated with superior safety in radiofrequency ablation. It is unclear if ICE has an impact on safety of CBA.

METHODS

The FREEZE Cohort (NCT01360008) subanalysis included patients undergoing "PVI only" CBA. Patients with intraprocedural transesophageal echocardiography were excluded. Group A comprises conventional, group B ICE-guided CBA. Periprocedural results were compared.

RESULTS

From 2011 to 2016, a total of 4189 patients were enrolled, and 1906 (45.5%) were included in this subanalysis, split up in two groups (A: 1066 [55.9%], B: 840 [44.1%]). Group A was younger (60.6 ± 10.8 vs. 62.4 ± 10.5 years, p < .001), with smaller left atria (41 vs. 43 mm, p < .001), and less persistent AF (23.1 vs. 38.1%, p < .001). Procedure, left atrial, and fluoroscopy times were shorter in group A as compared to group B. Dose area product was significantly higher in group A (2911 vs. 2072 cGyxcm2 , p < .001). In-hospital major adverse cerebrovascular and cardiac event rates including two deaths in group A were not different between groups (0.5% vs. 0.1%, p = .18). The rate of total procedural (10.4% vs. 5.1%, p < .001) and major complications (3.2% vs. 1.3%, p < .001) was significantly higher in group A. Cardiac tamponade occurred significantly more frequently in group A (8 [0.8%] vs. 1 [0.1%], p = .046). Independent predictors for major complications were female sex (odds ratio [OR] 2.03, p = .03) and non-ICE usage (OR 2.38, p = .02). No differences were observed for persistent phrenic nerve palsy, nor for groin complications.

CONCLUSION

CBA was significantly safer and required less radiation if ICE was used, although the procedures were more complex. The risk of groin complications was not increased with ICE usage. Non-ICE usage was the only modifiable independent predictor of major complications.

Adverse events in cryoballoon ablation for pulmonary vein isolation: Insight from the Food and Drug Administration Manufacturer and User Facility Device Experience

Background

Real-world clinical data on the adverse events related to the use of cryoballoon catheter for pulmonary vein isolation remains limited.

Objective

To report and describe the adverse events related to the use of Artic Front cryoballoon catheters (Arctic Front, Arctic Front Advance, and Arctic Front Advance Pro) reported in the Food and Drug Administration's (FDA) Manufacturers and User Defined Experience (MAUDE) database.

Methods

We reviewed all the adverse events reported to the FDA MAUDE database over a 10.7-year study period from January 01, 2011 to September 31, 2021. All events were independently reviewed by two physicians.

Results

During the study period, a total of 320 procedural-related adverse events reported in the MAUDE database were identified. The most common adverse event was transient or persistent phrenic nerve palsy (PNP), accounting for 48% of all events. This was followed by cardiac perforation (15%), pulmonary vein stenosis (8%), transient ischemic attack or stroke (6%), vascular injury (4%), transient or persistent ST-elevation myocardial infarction (3%), hemoptysis (2%), pericarditis (2%), and esophageal ulcer or fistula (1%). There were six reported intra-procedural death events as a result of cardiac perforation.

Conclusion

The two most common procedural adverse events associated with cryoballoon ablation were PNP and cardiac perforation. All cases of procedural mortality were due to cardiac perforation.

Wide Antral Circumferential Re-Ablation for Recurrent Atrial Fibrillation after Prior Pulmonary Vein Isolation Guided by High-Density Mapping Increases Freedom from Atrial Arrhythmias

Performing repeated pulmonary vein isolation (re-PVI) after recurrent atrial fibrillation (AF) following prior PVI is a standard procedure. However, no consensus exists regarding the most effective approach in redo procedures. We assessed the efficacy of re-PVI using wide antral circumferential re-ablation (WACA) supported by high-density electroanatomical mapping (HDM) as compared to conventional re-PVI. Consecutive patients with AF recurrences showing true PV reconnection (residual intra-PV and PV antral electrical potentials within the initial ablation line) or exclusive PV antral potentials (without intra-PV potentials) in the redo procedure were prospectively enrolled and received HDM-guided WACA (Re-WACA group). Conventional re-PVI patients treated using pure ostial gap ablation guided by a circular mapping catheter served as a historical control (Re-PVI group). Patients with durable PVI and no antral PV potentials were excluded. Arrhythmia recurrences ≥30 s were calculated as recurrences. In total, 114 patients were investigated (Re-WACA: n = 56, 68 ± 10 years, Re-PVI: n = 58, 65 ± 10 years). There were no significant differences in clinical characteristics including the AF type or the number of previous PVIs. In the Re-WACA group, 11% of patients showed electrical potentials only in the antrum but not inside any PV. At 402 ± 71 days of follow-up, the estimated freedom from arrhythmia was 89% in the Re-WACA group and 69% in the Re-PVI group (p = 0.01). Re-WACA independently predicted arrhythmia-free survival (HR = 0.39, 95% CI 0.16-0.93, p = 0.03), whereas two previous PVI procedures predicted recurrences (HR = 2.35, 95% CI 1.20-4.46, p = 0.01). The Re-WACA strategy guided by HDM significantly improved arrhythmia-free survival as compared to conventional ostial re-PVI. Residual PV antral potentials after prior PVI are frequent and can be easily visualized by HDM.

Incidence of Long-Term Pulmonary Vein Reconnection after a 2-Minute Cryoballoon Freeze for Pulmonary Vein Isolation—Invasive Insights of TTI-Dependent Cryoenergy Titration

Introduction: The optimal freeze duration in cryoballoon pulmonary vein isolation (PVI) is unknown. TTI-based titration of cryoenergy allows individualized freeze duration and has emerged as a favorable ablation strategy in PV cryoablation. In a recent study, we demonstrated that omission of a bonus freeze and reduction in freeze duration to a minimum of 2 min in the case of short TTI led to comparable arrhythmia recurrence rates. Whereas clinical outcome seems to be comparable to fixed freeze duration, evidence of long-term PV reconnection rates in patients undergoing TTI-based cryoballoon ablation is sparse. Aim of the study: To evaluate the procedural efficacy of a single 2-min freeze for PVI, we assessed PV conduction recovery after cryoballoon PVI with a TTI-guided titration of freeze duration compared to a fixed ablation protocol. Methods and Results: We included consecutive patients with atrial fibrillation (AF) recurrence undergoing a second ablation procedure after the initial cryoballoon procedure. The second AF ablation procedure was performed by the 3D-mapping system and radiofrequency ablation technique. A total of 219 patients (age: 66.2 ± 10.8 years, 53% female, paroxysmal AF: 53%) treated with the TTI-guided protocol (174 patients, 685 PV) or fixed protocol (45 patients, 179 PV) showed comparable total reconnection rates (TTI: 36.9% vs. fixed: 31.8%, p = 0.21). The PV reconnection rate was not statistically different for PVs treated with a 2-min freeze in case of short TTI, compared to longer freeze duration. Interestingly, the PV reconnection rate was lower in LIPVs treated with the fixed protocol (13% vs. 31%, p = 0.029). In the TTI group, 17 out of 127 patients (15%) had durable isolation of all PVs, whereas in 8 out of 40 patients (20%) in the fixed group, all PVs were still isolated (p = 0.31). Conclusions: overall reconnection rate was not different using a TTI-guided ablation protocol compared to a fixed ablation protocol, whereas the LIPV reconnection rate was significantly lower in patients treated with a fixed ablation protocol.

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.

Cardiac computed tomography angiography-derived analysis of left atrial appendage morphology and left atrial dimensions for the prediction of atrial fibrillation recurrence after pulmonary vein isolation

Background

Left atrial appendage (LAA) is a potential source of atrial fibrillation (AF) triggers.

Hypothesis

LAA morphology and dimensions are associated with AF recurrence after pulmonary vein isolation (PVI).

Methods

From cardiac computed tomography angiography (CCTA), left atrial (LA), pulmonary vein (PV), and LAA anatomy were assessed in cryoballoon ablation (CBA) patients.

Results

Among 1103 patients undergoing second‐generation CBA, 725 (65.7%) received CCTA with 473 (42.9%) qualifying for detailed LAA analysis (66.3 ± 9.5 years). Symptomatic AF reoccurred in 166 (35.1%) patients during a median follow‐up of 19 months. Independent predictors of recurrence were LA volume, female sex, and mitral regurgitation ≥°II. LAA volume and AF‐type were dependent predictors of recurrence due to their strong correlations with LA volume. LA volumes ≥122.7 ml (sensitivity 0.53, specificity 0.69, area under the curve [AUC] 0.63) and LAA volumes ≥11.25 ml (sensitivity 0.39, specificity 0.79, AUC 0.59) were associated with recurrence. LA volume was significantly smaller in females. LAA volumes showed no sex‐specific difference. LAA morphology, classified as windsock (51.4%), chicken‐wing (20.7%), cactus (12.5%), and cauliflower‐type (15.2%), did not predict successful PVI (log‐rank; p = 0.596).

Conclusions

LAA volume was strongly correlated to LA volume and was a dependent predictor of recurrence after CBA. Main independent predictors were LA volume, female sex, and mitral regurgitation ≥°II. Gender differences in LA volumes were observed. Individual LAA morphology was not associated with AF recurrence after cryo‐PVI. Our results indicate that preprocedural CCTA might be a useful imaging modality to evaluate ablation strategies for patients with recurrences despite successful PVI.

Optimizing cryoballoon pulmonary vein isolation: lessons from >1000 procedures- the Frankfurt approach

AIMS

Cryoballoon (CB) pulmonary vein isolation (PVI) is an accepted ablation strategy for rhythm control in atrial fibrillation (AF). We describe efficacy and safety in a high volume centre with a long experience in the use of the second-generation CB (CB2).

METHODS AND RESULTS

Consecutive paroxysmal AF (PAF) or persistent AF (persAF) patients undergoing CB2-PVI were enrolled. Procedural data, efficacy, and safety issues were systematically collected. The 28 mm CB2 was used in combination with an inner lumen spiral catheter, a luminal oesophageal temperature (LET) probe was used with a cut-off of 15°C, the phrenic nerve (PN) monitored during septal PVs ablation. Freeze duration was mainly set at 240 s with a bonus application in case of delayed time-to-isolation (TTI > 75 s). A total of 1017 CB2 procedures were analysed (58% male, 66 ± 12 years old, 70% with PAF). 3964 PVs were identified, 99.8% PVs isolated using solely the 28 mm CB. Mean procedure time was 69 ± 25 min, TTI during the first application was recorded in 77% of PVs after a mean of 48 ± 31 s. We recorded 0.2% cardiac tamponade, 4.8% PN injury (1.6% of PN palsy), and 19% of LET < 15°C. Among 725 patients with follow-up data, 84% with PAF and 75% with persAF were in stable SR at 1 year. Shorter freezing duration and longer TTI were procedural predictors for recurrence.

CONCLUSION

Cryoballoon procedures are fast and associated with a benign safety profile. Shorter TTI and longer freeze durations are associated with sinus rhythm during follow-up.

Impact of age on the outcome of cryoballoon ablation as the primary approach in the interventional treatment of atrial fibrillation: Insights from a large all-comer study

INTRODUCTION

The objective was to analyze the impact of patient age on clinical characteristics, procedural results, safety, and outcome of cryoballoon ablation (CBA) as the primary approach in the interventional treatment of symptomatic atrial fibrillation (AF).

METHODS AND RESULTS

The single-center prospective observational study investigated consecutive patients who underwent initial left atrial ablation for symptomatic paroxysmal (PAF) or persistent AF (persAF). Age groups (A-F) of less than 40, 40-49, 50-59, 60-69, 70-79 and more than or equal to 80 years were evaluated. Follow-up (FU) included ECG, Holter monitoring and assessment of AF-symptoms. From 2012 to 2016, a total of 786 patients (64 ± 11 years, range 21-85) underwent CBA. With advancing age, more cardiovascular comorbidities and larger LA diameter were observed, more females were included (each p < .001). PAF (57%) and persAF (43%, p = .320) were equally distributed over all age groups. Age was neither related to procedural parameters, nor to the complication rate (3.9%, p = .233). Median FU was 38 months. Two non-procedure related noncardiac deaths occurred late during FU. Freedom from arrhythmia was independent of age at 18 months (p = .210) but decreased for patients more than or equal to 70 years at 24 months (p = .02). At 36 months, freedom from arrhythmia was 66%-74% (groups A-D), 54% (E) and 49% (F), respectively (p = .002). LA diameter and persAF were independent predictors, whereas age was a dependent predictor of recurrence.

CONCLUSION

CBA as the primary approach in the initial ablation procedure is safe and highly effective in the young, middle aged, and elderly population. LA diameter and persAF, but not ageing, were independent predictors for arrhythmia recurrence.

Ablation for paroxysmal atrial fibrillation-real-life results from a middle-volume electrophysiology laboratory

Introduction

A significant improvement in safety and efficacy of ablation for paroxysmal atrial fibrillation (PAF) has been reported by experienced centers over recent years; however, data from real-life surveys and smaller electrophysiology (EP) laboratories have been less optimistic.

Aim

To asses efficacy of ablation for PAF in a middle-volume EP center over last years.

Methods

Retrospective analysis of 1 year efficacy and safety of ablation for PAF in three cohorts of patients treated between 2011 and 2014 (period I), 2015–2017 (period II), and 2018–2019 (period III).

Results

Of 234 patients (mean age 57 ± 9 years, 165 males), 81 (35%) were treated in period I, 84 (36%) in period II, and 69 (29%) in period III. The overall efficacy of ablation during all analyzed periods was 67%. The overall efficacy of ablation increased over time—from 56% in period I to 68% in period II and 81% in period III. Significant improvement was achieved using radiofrequency ablation (RF) (53% in period I vs 82% in period III, and 55% in period II vs 82% in period III, p = 0.003 and 0.0012, respectively) whereas positive trend in the improvement of cryoballoon efficacy was NS. The rate of peri-procedural complications was 9% and it did not change significantly over time.

Conclusions

This real-life observational study from a medium volume EP center shows that progress in PAF ablation, especially RF, reported by highly-skilled centers, can be reproduced in real life by less experienced operators.

Contemporary analysis of phrenic nerve injuries following cryoballoon-based pulmonary vein isolation: A single-centre experience with the systematic use of compound motor action potential monitoring

BACKGROUND

Phrenic nerve injury (PNI) remains one of the most frequent complications during cryoballoon-based pulmonary vein isolation (CB-PVI). Since its introduction in 2013, the use of compound motor action potential (CMAP) for the prevention of PNI during CB-PVI is increasing; however, systematic outcome data are sparse.

METHODS

The CMAP technique was applied in conjunction with abdominal palpation during pacing manoeuvres (10 mV, 2 ms) from the superior vena cava for 388 consecutive patients undergoing CB-PVI between January 2015 and May 2017 at our tertiary arrhythmia centre. Cryoablation was immediately terminated when CMAP amplitude was reduced by 30%.

RESULTS

Reductions in CMAP amplitude were observed in 16 (4%) of 388 patients during isolation of the right veins. Of these, 11 (69%) patients did not manifest a reduction in diaphragmatic excursions. The drop in CMAP amplitude was observed in 10 (63%) patients during ablation of the right superior pulmonary veins (PVs) and in 7 (44%) patients during ablation of the right inferior PVs. Postprocedural persistent PNI was observed in three of four patients for a duration of 6 months, with one of these patients remaining symptomatic at the 24-month follow-up. One of the four patients was lost to long-term follow-up.

CONCLUSIONS

All PNIs occurred during right-sided CB-PVI and were preceded by a reduction in CMAP amplitude. Thus, the standardized use of CMAP surveillance during CB-PVI is easily applicable, reliable and compared with other studies, results in a lower number of PNIs.

Cryoballoon or radiofrequency ablation? Alternating technique for repeat procedures in patients with atrial fibrillation

BACKGROUND

Which technique is better for repeat ablation in patients with atrial fibrillation (AF) remains unclear. The aim of the study was to compare long-term efficacy of repeat ablation using the alternative technique for the first redo ablation procedure: (a) cryoballoon (CB) re-ablation after a failed index pulmonary vein isolation (PVI) with radiofrequency (RF) ablation, RF-then-CB group or (b) RF repeat ablation following a failed CB ablation, CB-then-RF group.

METHODS

Within the 1STOP Italian Project, consecutive patients undergoing repeat ablation with a different technique from the index procedure were included.

RESULTS

We studied 474 patients, 349 in RF-then-CB and 125 in CB-then-RF group. Less women (21% vs 30%; P = .041), more persistent AF (33% vs 22%; P = .015), longer duration of AF (60 vs 31 months; P < .001), and more hypertension (50% vs 36%; P = .007) were observed in the RF-then-CB cohort as compared with the CB-then-RF group. The number of reconnected PVs was 3.7 ± 0.7 and 1.4 + 1.3 in RF-then-CB and CB-then-RF group, respectively (P < .001). During the follow-up, significantly less AF recurrence occurred in the CB-then-RF group (22% vs 8%, HR = 0.46; 95% CI: 0.24-0.92; P = .025). Cohort designation was the only independent predictor of AF recurrence.

CONCLUSION

Alternation of energy source for repeat ablation was safe and effective, regardless the energy used first. However, patients initially treated with CB PVI undergoing repeat ablation with RF current had less AF recurrence at long-term follow-up as compared with those originally treated by RF ablation receiving a CB repeat ablation.

Balloon-Based Ablation Technologies

Pulmonary vein isolation (PVI) is widely accepted as the mainstay of interventional treatment of atrial fibrillation. Ablation with radiofrequency (RF) point-by-point catheters is highly operator dependent and may fail because of ineffective lesions or gaps. Several balloon-based catheter ablation technologies have emerged as an alternative to effect PVI. Cryoballoon ablation is widely used, and current iterations of the technology show comparable acute and long-term efficacy to RF ablation. Techniques such as time to isolation have emerged to improve efficacy and safety. Laser balloon is a highly compliant variably sized balloon that has been validated as an effective strategy for PVI.

Long-term outcomes after second-generation cryoballoon ablation of paroxysmal atrial fibrillation - Feasibility of a single short freeze strategy without bonus applications

BACKGROUND

A paucity of data exists about long-term outcomes after second-generation cryoballoon ablation (2nd-CBA), and the feasibility of short freeze strategies remains under debate. We assessed the long-term follow-up outcomes.

METHODS

This study included 186 paroxysmal atrial fibrillation (PAF) patients (62 ± 11 years, 136 men) who underwent 2nd-CBAs with a 28-mm balloon and single 3-min freeze strategy without bonus applications. Fourteen-day consecutive monitoring was performed to detect early AF recurrences (ERAFs).

RESULTS

Overall, 713/736(96.9%) PVs were isolated with CBs. The total number of applications/patient was 5.3 ± 1.5. The total procedure and fluoroscopic times were 79.9 ± 28.1 and 24.4 ± 14.2 min. Asymptomatic right phrenic nerve injury occurred in 11 patients, however, all recovered during the follow-up. A total of 76(41.7%) patients experienced ERAFs. During a median 45.0 [30.0-51.0] month follow-up, the single procedure AF freedom was 76.1, 73.5, 70.5, and 63.7% at 1, 2, 3, and 4 years, respectively. At a median of 7.0 [4.0-12.0] months after the initial procedure, 35 (18.8%) patients underwent second procedures, and 106/137 (77.4%) PVs were still isolated. The multiple procedure AF freedom was 91.7, 89.3, 86.8, and 81.3% at 1, 2, 3, and 4 years, respectively. A Cox's proportional hazards model determined that the presence of ERAF was associated with a greater risk of recurrence after the last procedure (Hazard ratio = 2.830; 95% confidence interval = 1.173-6.833; p = 0.021). The percentage of continuation of anticoagulation therapy after the initial procedure was 33.1, 23.5, 21.7, and 21.7% at 1, 2, 3, and 4 years, respectively.

CONCLUSIONS

Our long-term follow-up data demonstrated the feasibility of a single short freeze strategy in PAF patients.

Feasibility, safety, and acute efficacy of the fourth-generation cryoballoon for ablation of atrial fibrillation: Another step forward?

Background

The second‐generation cryoballoon (CB2) is widely used for pulmonary vein (PV) isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). Recently, the novel fourth‐generation CB (CB‐Advance PRO) was introduced, incorporating a shortened catheter tip.

Hypothesis

The aim of this study was to evaluate the feasibility and acute efficacy of PVI using the CB‐Advance PRO.

Methods

A total of 200 consecutive patients were analyzed. Hundred patients who underwent PVI due to symptomatic, drug‐refractory AF were treated with the CB‐Advance PRO (group I) and were included into this multicenter analysis. A group of 100 patients were treated with the CB2 and acted as controls (group II).

Results

In total, 739 of 739 PVs (100%) were successfully isolated. There was a nonsignificant trend in the incidence of online registration of PV signals between both groups (group I: 77.9% vs group II: 71.4%, P = .09). Median time to PVI (time to isolation [TTI]) and mean total freezing time were significantly shorter when using the CB‐Advance PRO (group I: 33 [23, 50] vs group II: 40 [26, 60] seconds and group I: 166 ± 29 vs group II: 183 ± 38 seconds, P < .01). In three of 100 (3%) patients of group I and one of 100 (1%) patients of group II, a transient phrenic nerve palsy occurred (P = .62).

Conclusion

The use of the novel CB‐Advance PRO is feasible and associated with a significant reduction in mean TTI and mean total freezing time as compared to the CB2.

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.

The fourth cryoballoon generation with a shorter tip to facilitate real-time pulmonary vein potential recording: Feasibility and safety results

INTRODUCTION

Time-to-isolation (TTI) guided ablation protocols have been developed to ensure durable pulmonary vein isolation (PVI) in cryoballoon ablation (CBA). The aim was to determine the feasibility and safety of the fourth generation cryoballoon (CBG4) with a shortened tip.

METHODS AND RESULTS

Consecutive patients scheduled for initial atrial fibrillation (AF) ablation were prospectively included. PVI with the 28 mm CBG4 and the latest 20 mm spiral-mapping catheter (SMC) was performed. A total of 302 pulmonary veins (PVs) in 76 patients (64.8 ± 10.4 years, paroxysmal AF 49%) were treated with 617 applications. Left atrium (LA) time, fluoroscopy time, and dose-area product were 65.5 ± 19.2 minutes, 14.6 ± 5.6 minutes, and 1094 (738; 2097) cGy·cm² , respectively. PVI in cryoballoon technique was achieved in 302 of 302 (100%) PVs. TTI was determined in 256 (84.8%) of PVs. The mean TTI was 45.3 ± 26.4 seconds. Single-shot isolation was achieved in 247 (82%) PVs. In 6 of 302 (2.0%) PV the SMC was changed to a stiff wire to isolate the PV because of instability, and in 17 of 302 (5.6%) of PVs, the 23 mm CB was used to isolate. No radiofrequency touch-up applications were applied. The mean nadir balloon temperature was -44.8°C ± 6.6°C. Balloon dislodgement during positioning occurred in 3 of 617 (0.5%) applications without complications. One PN palsy occurred which resolved until discharge. One patient suffered from the inflammatory syndrome.

CONCLUSION

The CBG4 with a shorter distal tip seems to be safe and effective, and allows determining the TTI in 84.8% of PVs. In case of balloon instability, the exchange of the SMC to a stiff wire or, in small PV, the 23 mm cryoballoon facilitate PVI.

Is the time between first diagnosis of paroxysmal atrial fibrillation and cryoballoon ablation a predictor of efficacy?

AIMS

Cryoablation is an indicated therapy for the treatment of recurrent atrial fibrillation through pulmonary vein isolation; however, the optimal time between first diagnosis of atrial fibrillation and cryoablation is still unknown. We aimed to assess the clinical efficacy and safety of early versus later treatment of patients with paroxysmal atrial fibrillation by cryoablation.

METHODS

Five hundred and ten patients underwent atrial fibrillation cryoablation and were prospectively followed for at least 6 months in 43 Italian cardiology centers. The population was divided into two groups according to the time since the first diagnosis of atrial fibrillation until the index cryoablation procedure. An early-treatment group had an elapsed time of 15 months or less from atrial fibrillation diagnosis until cryoablation, and the late-treatment group had an elapsed time of greater than 15 months. During the evaluation, clinical efficacy was defined as atrial fibrillation recurrence outside a landmark 90-day blanking period, and safety was defined as the reporting of all procedure-related complications.

RESULTS

In the total cohort, cryoablation was performed after a median of 36 months from the point of the patient diagnosis with drug refractory symptomatic recurrent atrial fibrillation. The early-treatment group was composed of 130 (25%) patients, whereas the late-treatment group had 380 (75%) patients. Both cohorts had similar baseline clinical characteristics. Of 510 patients, 22 had a complication related to the procedure with no difference between the two groups. Multivariable analysis showed that the risk of atrial fibrillation recurrence was significantly higher in the late-treatment group (hazard ratio: 1.77; 95% confidence interval 1.00-3.13) CONCLUSION: In our multicenter observational examination, cryoablation was well tolerated and effective in the treatment of patients with drug refractory symptomatic paroxysmal atrial fibrillation. Reducing the time between diagnosis and ablation brought about a treatment that had a lower risk of atrial fibrillation recurrence with no change in safety.(Italian ClinicalService Project: NCT01007474).

Cryoballoon ablation of atrial fibrillation is effectively feasible without previous imaging of pulmonary vein anatomy: insights from the 1STOP project

BACKGROUND

Pulmonary vein isolation by cryoablation (PVI-C) is a standard therapy for the treatment of atrial fibrillation (AF); however, PVI-C can become a challenging procedure due to the anatomy of the left atrium and pulmonary veins (PVs). Importantly, the utility of imaging before the procedure is still unknown regarding the long-term clinical outcomes following PVI-C. The aim of the analysis is to evaluate the impact of imaging before PVI-C on procedural data and AF recurrence.

METHODS

Patients with paroxysmal AF underwent an index PVI-C. Data were collected prospectively in the framework of 1STOP ClinicalService® project. Patients were divided into two groups according to the utilization of pre-procedural imaging of PV anatomy (via CT or MRI) or the non-usage of pre-procedural imaging.

RESULTS

Out of 912 patients, 461 (50.5%) were evaluated with CT or MRI before the PVI-C and denoted as the imaging group. Accordingly, 451 (49.5%) patients had no pre-procedural imaging and were categorized as the no imaging group. Patient baseline characteristics were comparable between the two cohorts, but the ablation centers that comprised the imaging group had fewer PVI-C cases per year than the no imaging group (p < 0.001). The procedure, fluoroscopy, and left atrial dwell times were significantly shorter in the no imaging cohort (p < 0.001). The rates of complications were significantly greater in the imaging group compared to the no imaging group (6.9% vs. 2.7%; p = 0.003); this difference was attributed to differences in transient diaphragmatic paralysis. The 12-month freedom from AF was 76.2% in the imaging group and 80.0% in the no imaging group (p = 0.390).

CONCLUSIONS

In our analysis, PVI-C was effective regardless of the availability of imaging data on PV anatomy.

Influence of balloon temperature and time to pulmonary vein isolation on acute pulmonary vein reconnection and clinical outcomes after cryoballoon ablation of atrial fibrillation

BACKGROUND

Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon ablation (CBA) for atrial fibrillation (AF). We investigated whether balloon temperature and time to PVI can be used to predict early PV reconduction (EPVR), including residual PV conduction and adenosine triphosphate-induced dormant conduction and the relation between touch-up ablation of EPVR sites and mid-term recurrence of AF.

METHODS

We obtained procedural and outcome data from the records of 130 consecutive patients who underwent CBA and followed up for 13.4 months.

RESULTS

EPVR was identified in 86 (17%) PVs of 61 (47%) patients. Balloon temperatures during 30 seconds (-27 ± 5.7°C vs -31 ± 5.5°C), 60 seconds (-36 ± 5.6°C vs -41 ± 5.4°C), and at the nadir point (-41 ± 7.4°C vs -49 ± 7.0°C) were significantly higher, and the time to PVI was longer (90 ± 50 seconds vs 52 ± 29 seconds) in PVs with EPVR than in those without (P < 0.0001 for all). Among PVs without EPVR, the time to PVI was longer and balloon temperature was lower for the left superior pulmonary vein/ right inferior pulmonary vein (LSPV/RIPV) than for the right superior pulmonary vein/left inferior pulmonary vein (RSPV/LIPV) (time: 60 ± 25/73 ± 37 seconds vs 41 ± 31/45 ± 20 seconds, P < 0.0001) (temp: -39.2 ± 11.3/-39.4 ± 8.3°C vs -33.8 ± 10.6/-33.6 ± 6.8°C, P = 0.0023). AF recurrence rates were equivalent between patients with and without EPVR (13% [8/69] vs 15% [9/61], P = 0.845).

CONCLUSIONS

Cryoballoon temperature and time to PVI appear to be useful in predicting durable PVI, that is, prevention of EPVR, but the balloon temperature and time required for PVI differ between PVs. Although EPVR does not predict AF recurrence, high success rates can be expected when touch-up ablation of EPVR sites is performed.

The slope of the initial temperature drop predicts acute pulmonary vein isolation using the second-generation cryoballoon

Aims

There is no objective, early indicator of occlusion quality, and efficacy of cryoballoon pulmonary vein isolation. As previous experience suggests that the initial cooling rate correlates with these parameters, we investigated the slope of the initial temperature drop as an objective measure.

Methods and results

A systematic evaluation of 523 cryoapplications in 105 patients using a serial ROC-AUC analysis was performed. We found the slope of a linear regression of the temperature-time function to be a good predictor (PPV 0.9, specificity 0.72, sensitivity 0.71, and ROC-AUC 0.75) of acute isolation. It also correlated with nadir temperatures (P< 0.001, adjusted R2= 0.43), predicted very low nadir temperatures, and varied according to visual occlusion grades (ANOVA P< 0.001).

Conclusions

About 25 s after freeze initiation, the temperature-time slope predicts important key characteristics of a cryoablation, such as nadir temperature. The slope is the only reported predictor to actually precede acute isolation and thus to support decisions about pull-down manoeuvres or aborting a cryoablation early on. It is also predictive of very low nadir temperatures and phrenic nerve palsy and thus may add to patient safety.

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.

Revisiting pulmonary vein isolation alone for persistent atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Early studies demonstrated relatively low success rates for pulmonary vein isolation (PVI) alone in patients with persistent atrial fibrillation (PeAF). However, the advent of new technologies and the observation that additional substrate ablation does not improve outcomes have created a new focus on PVI alone for treatment of PeAF.

OBJECTIVE

The purpose of this study was to systematically review the recent medical literature to determine current medium-term outcomes when a PVI-only approach is used for PeAF.

METHODS

An electronic database search (MEDLINE, Embase, Web of Science, PubMed, Cochrane) was performed in August 2016. Only studies of PeAF patients undergoing a "PVI only" ablation strategy using contemporary radiofrequency (RF) technology or second-generation cryoballoon (CB2) were included. A random-effects model was used to assess the primary outcome of pooled single-procedure 12-month arrhythmia-free survival. Predictors of recurrence were also examined and a meta-analysis performed if ≥4 studies examined the parameter.

RESULTS

Fourteen studies of 956 patients, of whom 45.2% underwent PVI only with RF and 54.8% with CB2, were included. Pooled single-procedure 12-month arrhythmia-free survival was 66.7% (95% confidence interval [CI] 60.8%-72.2%), with the majority of patients (80.5%) off antiarrhythmic drugs. Complication rates were very low, with cardiac tamponade occurring in 5 patients (0.6%) and persistent phrenic nerve palsy in 5 CB2 patients (0.9% of CB2). Blanking period recurrence (hazard ratio 4.68, 95% CI 1.70-12.9) was the only significant predictor of recurrence.

CONCLUSION

A PVI-only strategy in PeAF patients with a low prevalence of structural heart disease using contemporary technology yields excellent outcomes comparable to those for paroxysmal AF ablation.

The Impact of Advances in Atrial Fibrillation Ablation Devices on the Incidence and Prevention of Complications

The number of patients with atrial fibrillation currently referred for catheter ablation is increasing. However, the number of trained operators and the capacity of many electrophysiology labs are limited. Accordingly, a steeper learning curve and technical advances for efficient and safe ablation are desirable. During the last decades several catheter-based ablation devices have been developed and adapted to improve not only lesion durability, but also safety profiles, to shorten procedure time and to reduce radiation exposure. The goal of this review is to summarise the reported incidence of complications, considering device-related specific aspects for point-by-point, multi-electrode and balloon-based devices for pulmonary vein isolation. Recent technical and procedural developments aimed at reducing procedural risks and complications rates will be reviewed. In addition, the impact of technical advances on procedural outcome, procedural length and radiation exposure will be discussed.

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.

Cryoballoon Ablation for Atrial Fibrillation: a Comprehensive Review and Practice Guide

The cryoballoon was invented to achieve circumferential pulmonary vein isolation more efficiently to compliment the shortcomings of point-by-point ablation by radiofrequency ablation (RFA). Its efficacy and safety were shown to be comparable to those of RFA, and the clinical outcomes have improved with the second-generation cryoballoon. The basic biophysics, implemental techniques, procedural recommendations, clinical outcomes, and complications of the cryoballoon are presented in this practical and systematic review.

Complications of Atrial Fibrillation Cryoablation

Catheter ablation either by using radiofrequency or cryo energy in symptomatic patients with atrial fibrillation (AF) has shown to be effective as compared to anti-arrhythmic drugs. However, all the techniques used during AF ablation are not free of complication. There are several well-known peri-procedural complications in which operators should be informed of the possible risks, cautious during the procedure and able to manage them when occurred. Herein, we aimed to review possible complications of AF cryoablation.

Cryoballoon vs. radiofrequency ablation for paroxysmal atrial fibrillation: an updated meta-analysis of randomized and observational studies

Aims

Radiofrequency (RF) ablation represents a standard of care for pulmonary vein isolation in patients with drug-refractory paroxysmal atrial fibrillation (AF). In this setting, cryoballoon (CB) ablation has emerged as alternative therapy. However, the efficacy and safety of CB vs. RF ablation in patients with paroxysmal AF remain a matter of debate.

Methods and results

We searched electronic scientific databases for studies of CB vs. RF ablation in patients with paroxysmal AF. Aggregate data were pooled to perform a meta-analysis. The primary efficacy and safety outcomes were the recurrence of any atrial arrhythmia and procedure-related complications, respectively. A total of 6473 participants from 10 studies (CB, n = 2232 vs. RF, n = 4241) were studied. After a median follow-up of 16 months, the risk of any atrial arrhythmia recurrence (risk ratio, RR 95% confidence interval [95% CI] = 1.01 [0.90-1.14], P = 0.83) and procedure-related complications (RR [95% CI] = 0.92 [0.66-1.28], P = 0.61) were comparable between CB vs. RF ablation. Cryoballoon ablation led to a higher risk of persistent phrenic nerve palsy (RR [95% CI] = 13.60 [3.87-47.81], P < 0.01) and a lower risk of cardiac tamponade (RR [95% CI] = 0.48 [0.25-0.89], P = 0.02) compared with RF ablation. There was a trend of statistically significant interaction between the type of CB and the duration of ablation (P for interaction = 0.09).

Conclusion

In patients with paroxysmal AF, ablation therapy with CB is associated with efficacy and safety comparable to that of RF. Second-generation CB catheters seem to reduce procedure duration. Further studies are warranted to disclose the impact of second-generation CB catheters compared with RF for ablation of paroxysmal AF.

Bonus vs No Bonus Cryoballoon Isolation for Paroxysmal Atrial Fibrillation Ablation

Aims

To evaluate the benefit of Bonus freeze using second generation cryoballoon after pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF).

Methods

A bonus freeze is performed after proven pulmonary vein isolation (PVI) for cryoballoon ablation of paroxysmal atrial fibrillation (PAF) as standard. In the current study, no additional freeze (No Bonus) after PVI was compared with additional freeze (Bonus) after PVI using second generation cryoballoon.

Results

A total of 136 patients (mean age 58 ± 13 years, 76 male) were included. No Bonus and Bonus groups had 56 and 80 patients, respectively. Follow-up electrocardiography and Holter monitoring were performed at 1, 3, 6, 12 months, and biannually thereafter. The PVI rate was similar after the initial ablation (82% in No Bonus group, 80% in Bonus group, p>0.05) and, at the end of the procedure (99% in No Bonus group and 99% in Bonus group, p>0.05). The median procedure and fluoroscopy times in No Bonus group were 67 (60-74) minutes and 13 (10-15) minutes, which were significantly shorter than the median durations, 85 (76-90) minutes and 17 (15-21) minutes in Bonus group, respectively (all p<0.001). Phrenic nerve palsy was observed less frequently in No Bonus group compared to Bonus group (1 patient (2%) vs. 5 patients (6%), respectively) without statistically significant difference. During a median follow-up of 13 (11-15) months, the rates of patients free from AF were 82% in No Bonus group and 84% in Bonus group, respectively (p>0.05).

Conclusions

The rate of sinus rhythm at 18 months was similar in patients with PAF who received bonus cryoablation vs patients who did not receive bonus cryoablation.

Cryoballoon ablation of atrial fibrillation: a practical and effective approach

Medical management of atrial fibrillation (AF), the most common arrhythmia in the general population, has had modest efficacy in controlling symptoms and restoring and maintaining sinus rhythm. Since the seminal observation in 1998 that pulmonary veins host the triggers of AF in the majority of cases, electrical isolation of all pulmonary veins constitutes the cornerstone of ablation in patients with symptomatic AF. However, due to the elaborate and tedious technique of the conventional point-by-point method with radiofrequency ablation guided by electroanatomical mapping, newer, more versatile single-shot techniques, such as cryoballoon ablation, have been sought and developed over recent years and are progressively prevailing. Cryoballoon ablation appears to be the most promising practical and effective approach, and we review it here by presenting all available relevant data from the literature as well as from our own experience in an attempt to apprise colleagues of the significant progress made over the last several years in this important field of electrophysiology.

Who Needs Catheter Ablation And Which Approach?

Catheter ablation therapy for atrial fibrillation (AF) has gained a significant role during maintenance of sinus rhythm compared to anti-arrhythmic medication. Catheter ablation techniques are also improved and progressed over years in parallel to better understanding of disease mechanisms and technological advancements. However, due to invasive nature of the therapy with its pertinent procedural risks, both appropriate patient selection and use of relevant approach should be considered by all electrophysiologists before decide to perform catheter ablation.

Quantitative Analysis of the Isolation Area During the Chronic Phase After a 28-mm Second-Generation Cryoballoon Ablation Demarcated by High-Resolution Electroanatomic Mapping

BACKGROUND

The post-second-generation cryoballoon (CB) ablation isolation area during the chronic phase has not been described. The aim of this study was to quantitatively evaluate the chronic-phase isolation area after 28-mm second-generation CB ablation and compare it to the estimated conventional radiofrequency circumferential pulmonary vein isolation (CPVI) line.

METHODS AND RESULTS

Thirty-two patients with paroxysmal atrial fibrillation underwent pulmonary vein (PV) isolation using second-generation CB. After a median of 6.0 (4.0-9.0) months, the PV isolation area was evaluated using high-resolution mapping (1-mm electrode, 2-mm interelectrode spacing; 527±99 points per map) and pacing techniques in all patients (17 with and 15 without arrhythmia recurrence beyond blanking period) and compared with estimated conventional radiofrequency CPVI area. PV reconnections were observed in 34 of 126 PVs (27.0%) among 21 of 32 patients (65.6%), which were eliminated by a median of 1.0 (1.0-3.0) focal radiofrequency application. The left- and right-sided PV antrum isolation area and nonablated posterior wall areas were 9.8±1.7, 8.1±2.3, and 17.0±6.1 cm(2), respectively. The cryoablated areas were significantly smaller than the estimated conventional radiofrequency CPVI areas in all but the right inferior PV. The difference was highest in the left superior PV. In 2 patients (6.3%), recurrent atrial fibrillation originated from the foci identified at the left superior PV antrum outside the CB isolation area but inside the estimated conventional radiofrequency CPVI line.

CONCLUSIONS

Although the PV isolation areas during the chronic phase after the second-generation CB ablation were generally wide, they were significantly smaller than the area encircled by the CPVI line except at the right inferior PV antrum. Recurrent atrial fibrillation could originate from the left superior PV antrum and could be isolated by a CPVI but not by a CB.