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Introduction: Catheter ablation of atrial fibrillation (AF) is frequently studied in randomized trials, observational and registry studies. The aim of this expert opinion is to provide guidance for clinicians and industry regarding the development of future clinical studies on catheter ablation of AF, implement lessons learned from previous studies, and promote a higher degree of consistency across studies., Background: Studies on catheter ablation of AF may benefit from well-described definitions of endpoints and consistent methodology and documentation of outcomes related to efficacy, safety and cost-effectiveness. The availably of new, innovative technologies warrants further consideration about their application and impact on study design and the choice of endpoints. Moreover, recent insights gained from AF ablation studies suggest a reconsideration of some methodological aspects., Methods: A panel of clinical experts on catheter ablation of AF and designing and conducting clinical studies developed an expert opinion on the design and endpoints for studies on catheter ablation of AF. Discussions within the expert panel with the aim to reach consensus on predefined topics were based on outcomes reported in the literature and experiences from recent clinical trials., Results: A comprehensive set of recommendations is presented. Key elements include the documentation of clinical AF, medication during the study, repeated ablations and their effect on endpoint assessments, postablation blanking and the choice of rhythm-related and other endpoints., Conclusion: This expert opinion provides guidance and promotes consistency regarding design of AF catheter ablation studies and identified aspects requiring further research to optimize study design and methodology., Condensed Abstract: Recent insights from studies on catheter ablation of atrial fibrillation (AF) and the availability of new innovative technologies warrant reconsideration of methodological aspects related to study design and the choice and assessment of endpoints. This expert opinion, developed by clinical experts on catheter ablation of AF provides a comprehensive set of recommendations related to these methodological aspects. The aim of this expert opinion is to provide guidance for clinicians and industry regarding the development of clinical studies, implement lessons learned from previous studies, and promote a higher degree of consistency across studies., (© 2024 The Author(s). Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Introduction: Three randomised controlled trials (RCTs) have demonstrated that first-line cryoballoon pulmonary vein isolation decreases atrial tachycardia in patients with symptomatic paroxysmal atrial fibrillation (PAF) compared with antiarrhythmic drugs (AADs). The aim of this study was to develop a cost-effectiveness model (CEM) for first-line cryoablation compared with first-line AADs for the treatment of PAF. The model used a Danish healthcare perspective., Methods: Individual patient-level data from the Cryo-FIRST, STOP AF and EARLY-AF RCTs were used to parameterise the CEM. The model structure consisted of a hybrid decision tree (one-year time horizon) and a Markov model (40-year time horizon, with a three-month cycle length). Health-related quality of life was expressed in quality-adjusted life years (QALYs). Costs and benefits were discounted at 3% per year. Model outcomes were produced using probabilistic sensitivity analysis., Results: First-line cryoablation is dominant, meaning it results in lower costs (-€2,663) and more QALYs (0.18) when compared to first-line AADs. First-line cryoablation also has a 99.96% probability of being cost-effective, at a cost-effectiveness threshold of €23,200 per QALY gained. Regardless of initial treatment, patients were expected to receive ∼ 1.2 ablation procedures over a lifetime horizon., Conclusion: First-line cryoablation is both more effective and less costly (i.e. dominant), when compared with AADs for patients with symptomatic PAF in a Danish healthcare system., (© 2024. The Author(s).)

Introduction: Three recent randomised controlled trials have demonstrated that pulmonary vein isolation as an initial rhythm control strategy with cryoablation reduces atrial arrhythmia recurrence in patients with symptomatic paroxysmal atrial fibrillation (PAF) compared with antiarrhythmic drug (AAD) therapy. The aim of this study was to evaluate the cost-effectiveness of first-line cryoablation compared with first-line AADs for treating symptomatic PAF in an English National Health Service (NHS) setting., Methods: Individual patient-level data from 703 participants with PAF enrolled into Cryo-FIRST (Catheter Cryoablation Versus Antiarrhythmic Drug as First-Line Therapy of Paroxysmal Atrial Fibrillation), STOP AF First (Cryoballoon Catheter Ablation in an Antiarrhythmic Drug Naive Paroxysmal Atrial Fibrillation) and EARLY-AF (Early Aggressive Invasive Intervention for Atrial Fibrillation) were used to derive the parameters applied in the cost-effectiveness model (CEM). The CEM comprised a hybrid decision tree and Markov structure. The decision tree had a 1-year time horizon and was used to inform the initial health state allocation in the first cycle of the Markov model (40-year time horizon; 3-month cycle length). Health benefits were expressed in quality-adjusted life years (QALYs). Costs and benefits were discounted at 3.5% per year. Model outcomes were generated using probabilistic sensitivity analysis., Results: The results estimated that cryoablation would yield more QALYs (+0.17) and higher costs (+£641) per patient over a lifetime than AADs. This produced an incremental cost-effectiveness ratio of £3783 per QALY gained. Independent of initial treatment, individuals were expected to receive ~1.2 ablations over a lifetime. There was a 45% relative reduction in time spent in AF health states for those initially treated with cryoablation., Discussion: AF rhythm control with first-line cryoablation is cost effective compared with first-line AADs in an English NHS setting., Competing Interests: Competing interests: JP reports consultancy payments and educational support received from Medtronic. JM, SM, TB, EL, DL report that Medtronic provided payment to York Health Economics (YHEC), a wholly owned subsidiary of the University of York, to conduct the statistical and cost-effectiveness analyses and write the manuscript. JA reports grants and personal fees from Medtronic, grants from Baylis, personal fees from Biosense-Webster. MK reports honoraria for teaching, participation in clinical trials, proctoring and lectures/presentations from Medtronic. OW reports grants from Medtronic and personal fees from Biosense Webster and Boston Scientific. GBC reports compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik, Boston Scientific, and Acutus Medical. EI, AS, MS, RK report being employees and stockholders of Medtronic. DT reports speaker’s fees from Boston Scientific and Abbott., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

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 cGyxcm 2 , 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., (© 2023 Wiley Periodicals LLC.)

Aims: Cryoballoon (CB)-based pulmonary vein isolation (PVI) is an effective treatment for atrial fibrillation (AF). The most frequent complication during CB-based PVI is right-sided phrenic nerve injury (PNI) which is leading to premature abortion of the freeze cycle. Here, we analysed reconnection rates after CB-based PVI and PNI in a large-scale population during repeat procedures., Methods and Results: In the YETI registry, a total of 17 356 patients underwent CB-based PVI in 33 centres, and 731 (4.2%) patients experienced PNI. A total of 111/731 (15.2%) patients received a repeat procedure for treatment of recurrent AF. In 94/111 (84.7%) patients data on repeat procedures were available. A total of 89/94 (94.7%) index pulmonary veins (PVs) have been isolated during the initial PVI. During repeat procedures, 22 (24.7%) of initially isolated index PVs showed reconnection. The use of a double stop technique did non influence the PV reconnection rate (P = 0.464). The time to PNI was 140.5 ± 45.1 s in patients with persistent PVI and 133.5 ± 53.8 s in patients with reconnection (P = 0.559). No differences were noted between the two populations in terms of CB temperature at the time of PNI (P = 0.362). The only parameter associated with isolation durability was CB temperature after 30 s of freezing. The PV reconnection did not influence the time to AF recurrence., Conclusion: In patients with cryoballon application abortion due to PNI, a high rate of persistent PVI rate was found at repeat procedures. Our data may help to identify the optimal dosing protocol in CB-based PVI procedures., Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03645577?term=YETI&cntry=DE&draw=2&rank=1 ClinicalTrials.gov Identifier: NCT03645577., Competing Interests: Conflict of interest: C.H.H. received travel grants and research grants from Medtronic, Boston Scientific, Biosense Webster and Cardiofocus and is a proctor and lecturer of Medtronic, Boston Scientific, Cardiofocus and Biosense Webster. K.H.K. received travel grants and research grants from Biosense Webster, Stereotaxis, Prorhythm, Medtronic, Edwards, Cryocath, and is a consultant to St. Jude Medical, Biosense Webster, Prorhythm, and Stereotaxis. He received speaker's honoraria from Medtronic. R.R.T. received travel grants from St. Jude Medical, Biosense Webster, Daiichi Sankyo, SentreHeart and Speaker’s Bureau Honoraria from Biosense Webster, Biotronik, Boston scientific, Pfizer, Topera, Bristol-Myers Squibb, Bayer, Sanofi Aventis, and research grants by Cardiofocus, Boston Scientific and Lifetech. K.A. is a proctor and lecturer for Medtronic, Biosense Webster, and Abbott. A.M. received speaker's honoraria and travel grants from Medtronic, Biosense Webster and Cardiofocus. F.S. received honoraria for lectures from Medtronic, Philips EPD Solutions, and Bristol-Myers-Squibb, outside the submitted work; and educational support from Pfizer. S.C. received travel grants and speaker’s honoraria from Medtronic, Biosense Webster and Abbott, and is a proctor of Medtronic. E.J.P. received consultant fees from Medtronic, Biotronik, Abbott, Boston Scientific. E.W. is a consultant to Medtronic. All other authors have no relevant disclosures., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Pulmonary vein isolation (PVI) is recommended to treat paroxysmal and persistent atrial fibrillation (AF). This analysis aimed to assess the hospital efficiency of single-shot cryoballoon ablation (CBA) and point-by-point radiofrequency ablation (RFA)., Methods: The discrete event simulation used PVI procedure times from the FREEZE Cohort study to establish the electrophysiology (EP) lab occupancy time. 1000 EP lab days were simulated according to an illustrative German hospital, including 3 PVI cases per day using CBA at one site and RFA at the other., Results: The analysis included 1560 CBA patients and 1344 RFA patients from the FREEZE Cohort. Some baseline patients' characteristics were different between groups (age, AF type, and some concomitant diseases), without being statistically associated to ablation procedure time. Mean procedure time was 122.2 ± 39.4 min for CBA and 160.3 ± 53.5 min for RFA (p < 0.0001). RFA was associated with a more than five-fold increase of cumulative overtime compared to CBA over the simulated period (1285 h with RFA and 253 h with CBA). 70.7% of RFA lab days included overtime versus 25.7% for CBA. CBA was associated with more days with an additional hour at the end of the EP lab shift compared to RFA (47.8% vs 11.5% days with one hour left, respectively)., Conclusion: CBA is faster and more predictable than point-by-point RFA, and enables improvements in EP lab efficiency, including: fewer cumulative overtime hours, more days where overtime is avoided and more days with remaining time for the staff or for any EP lab usage. Clinical trial registration NCT01360008 (first registration 25/05/2011)., (© 2023. The Author(s).)

Atrial fibrillation (AF) is a commonly encountered chronic and progressive heart rhythm disorder, characterized by exacerbations and remissions. Contemporary clinical practice guidelines recommend a trial of antiarrhythmic drugs (AADs) as the initial therapy for sinus rhythm maintenance; however, these medications have modest efficacy and are associated with significant adverse effects. Recently, several trials have demonstrated that an initial treatment strategy of cryoballoon catheter ablation significantly improves arrhythmia outcomes (e.g. freedom atrial tachyarrhythmia and reduction in arrhythmia burden), produces clinically meaningful improvements in patient-reported outcomes (e.g. symptoms and quality of life), and significantly reduces subsequent healthcare resource utilization (e.g. hospitalization), without increasing the risk of serious or any adverse events. These findings are relevant to patients, providers, and healthcare systems, helping inform the decision regarding the initial choice of rhythm-control therapy in patients with treatment-naïve AF., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2022. For permissions, please email: journals.permissions@oup.com.)

Background: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce., Methods: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible., Results: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 10 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was -49±8°C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months., Conclusions: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03645577. Graphic Abstract: A graphic abstract is available for this article.

Background: Cryoballoon ablation (CBA) as a first-line rhythm control strategy is superior to antiarrhythmic drugs (AADs) for preventing atrial fibrillation (AF) recurrence; the impact of first-line CBA on quality of life (QoL) and symptoms has not been well characterized., Methods: Patients aged 18 to 75 with symptomatic paroxysmal AF naïve to rhythm control therapy were randomized (1:1) to CBA (Arctic Front Advance, Medtronic) or AAD (Class I or III). Symptoms and QoL were assessed at baseline, 1, 3, 6, 9, and 12 months using the EHRA classification and Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) and SF-36v2 questionnaires. Symptomatic palpitations were evaluated via patient diary., Results: Overall, 107 patients were randomized to CBA and 111 to AAD; crossovers occurred in 9%. Larger improvements in the AFEQT summary, subscale and treatment satisfaction scores were observed at 12 months with CBA vs AAD (all P <0.05). At 12 months, the mean adjusted difference in the AFEQT summary score was 9.9 points higher in the CBA group (95% CI: 5.5 -14.2, P <0.001). Clinically important improvements in the SF-36 physical and mental component scores were observed at 12 months in both groups, with no significant between group differences at this timepoint. In the CBA vs AAD group, larger improvements in EHRA class were observed at 6, 9 and 12 months (P <0.05) and the incidence rate of symptomatic palpitations was lower (4.6 vs 15.2 days/year post-blanking; IRR: 0.30, P <0.001)., Conclusions: In patients with symptomatic AF, first-line CBA was superior to AAD for improving AF-specific QoL and symptoms., Trial Registration: ClinicalTrials.gov number: NCT01803438., (Copyright © 2021. Published by Elsevier Inc.)

Atrial fibrillation (AF), the most common sustained arrhythmia observed in clinical practice, is a chronic and progressive disorder characterized by exacerbations and remissions. Guidelines recommend antiarrhythmic drugs as the initial therapy for the maintenance of sinus rhythm; however, antiarrhythmic drugs have modest efficacy to maintain sinus rhythm and can be associated with significant adverse effects. An initial treatment strategy of cryoballoon catheter ablation in patients with treatment-naïve AF has been shown to significantly improve arrhythmia outcomes (freedom from any, or symptomatic atrial tachyarrhythmia), produce clinically meaningful improvements in patient-reported outcomes (symptoms and quality of life), and significantly reduce subsequent health care resource use (hospitalization), and it does not increase the risk of serious or any adverse events compared with initial antiarrhythmic drug therapy. These findings are relevant to inform patients, providers, and health care systems regarding the initial choice of rhythm-control therapy in patients with treatment-naïve AF., Competing Interests: Funding Support and Author Disclosures The EARLY-AF Trial was funded by a peer-reviewed grant from the Cardiac Arrhythmia Network of Canada (grant number SRG-15-P15-001), with additional unrestricted support from Medtronic and Baylis Medical. The STOP-AF First trial and the Cryo-FIRST trial were supported by Medtronic. Dr Andrade has received grants and personal fees from Medtronic; has received grants from Baylis; and has received personal fees from Biosense Webster. Dr Wazni has received grants from Medtronic; and has received personal fees from Biosense Webster and Boston Scientific. Dr Kuniss has received speaker fees from Abbott and Medtronic; has provided proctoring, consultancy, and advisory board services for Medtronic; and has received research grants from Medtronic and Biosense Webster. Dr Deyell has received grants and personal fees from Biosense Webster; and has received personal fees from Medtronic and Abbott. Dr Chierchia has received speaker fees from Medtronic, Biotronik, Biosense Webster, and Abbott. Dr Nissen has received grants from Medtronic. Dr Verma has received grant support from Biotronik, Bristol Myers Squibb, and Boehringer Ingelheim; has received grant support, advisory board fees, and lecture fees from Bayer and Biosense Webster; has received advisory board fees and lecture fees from and served as principal investigator (PULSED AF and DIAMOND II trial) for Medtronic; has received consulting fees from and served on steering committees for Boston Scientific, Kardium, Medlumics, and Thermedical; and has received lecture fees from Servier. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Although cryoballoon ablation of atrial fibrillation (AF) traditionally has been guided by pulmonary vein (PV) occlusion, there is evidence and growing interest in performing segmental, nonocclusive cryoballoon ablation to target not only large/common PVs but extra-PV structures such as the left atrial (LA) roof and posterior wall in conjunction with PV isolation. A number of studies have demonstrated improved clinical efficacy associated with nonocclusive cryoballoon ablation of the LA roof and posterior wall in addition to PV isolation, particularly in patients with persistent AF. Not only can the cryoballoon be used for targeting extra-PV structures through segmental, nonocclusive ablation, but the large size and durability of cryolesions coupled with the enhanced stability afforded through cryoadhesion render the cryoballoon an effective tool for such an approach. This article reviews the rationale and practical approach to segmental, nonocclusive cryoballoon ablation of large/common PV antra and the LA roof and posterior wall., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Treatment guidelines for patients with atrial fibrillation (AF) suggest that patients should be managed with an antiarrhythmic drug (AAD) before undergoing catheter ablation (CA). This study evaluated whether pulmonary vein isolation employing cryoballoon CA is superior to AAD therapy for the prevention of atrial arrhythmia (AA) recurrence in rhythm control naive patients with paroxysmal AF (PAF)., Methods and Results: A total of 218 treatment naive patients with symptomatic PAF were randomized (1 : 1) to cryoballoon CA (Arctic Front Advance, Medtronic) or AAD (Class I or III) and followed for 12 months. The primary endpoint was ≥1 episode of recurrent AA (AF, atrial flutter, or atrial tachycardia) >30 s after a prespecified 90-day blanking period. Secondary endpoints included the rate of serious adverse events (SAEs) and recurrence of symptomatic palpitations (evaluated via patient diaries). Freedom from AA was achieved in 82.2% of subjects in the cryoballoon arm and 67.6% of subjects in the AAD arm (HR = 0.48, P = 0.01). There were no group differences in the time-to-first (HR = 0.76, P = 0.28) or overall incidence [incidence rate ratio (IRR)=0.79, P = 0.28] of SAEs. The incidence rate of symptomatic palpitations was lower in the cryoballoon (7.61 days/year) compared with the AAD arm (18.96 days/year; IRR = 0.40, P < 0.001)., Conclusions: Cryoballoon CA was superior to AAD therapy, significantly reducing AA recurrence in treatment naive patients with PAF. Additionally, cryoballoon CA was associated with lower symptom recurrence and a similar rate of SAEs compared with AAD therapy., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: It is unknown whether left atrial (LA) roof ablation combined with pulmonary vein isolation (PVI) using a second-generation cryoballoon provides additional benefit beyond that of PVI alone in patients with persistent atrial fibrillation (AF). The aim of this study was to compare arrhythmia recurrence rates after PVI alone versus PVI plus LA roof ablation., Methods and Results: In this observational study, we analyzed 399 symptomatic patients with persistent AF treated with cryoballoon ablation. After univariate and multivariate analyses of the entire cohort, propensity score matching resulted in two groups of 86 patients each: (1) PVI plus LA roof ablation (PVI-plus group) and (2) PVI alone (PVI-only group). The primary endpoint was the first documented > 30-s arrhythmia recurrence after a 3-month blanking period. PVI was successful in all patients. A bidirectional conduction block across the LA roof was verified in 91.9% of patients in the PVI-plus group. During a median mid-term follow-up of 33 months, 21 patients (24.4%) in the PVI-plus group and 37 patients (43.0%) in the PVI-only group (P = 0.01) reached the primary endpoint. Multivariate analysis revealed AF history > 2 years (hazard ratio [HR] = 2.04, P < 0.01), LA area > 21 cm 2 (HR = 2.36, P < 0.01), female sex (HR = 1.92, P = 0.02), and LA roof ablation (HR = 0.47, P < 0.01) as significant predictors of outcome., Conclusions: We observed a significant difference in arrhythmia recurrence rates between the two groups. LA roof ablation is an effective adjuvant treatment option that shows improved outcome compared with PVI alone.

Background: Radiofrequency current (RFC) catheter ablation for patients with paroxysmal atrial fibrillation (AF) has been shown to be safe and effective in first-line therapy. Recent data demonstrates that RFC ablation provides better clinical outcomes compared to antiarrhythmic drug (AAD) in the treatment of early AF disease. Furthermore, studies comparing RFC and cryoballoon have established comparable efficacy and safety of pulmonary vein isolation (PVI) for patients with symptomatic paroxysmal AF., Objectives: The Cryo-FIRST trial was designed to compare AAD treatment against cryoballoon PVI as a first-line therapy in treatment naïve patients with AF. Efficacy and safety will be compared between the two cohorts and amongst subgroups., Methods: The primary hypothesis is that cryoablation is superior to AAD therapy. To test this hypothesis, patients will be randomized in a 1:1 design. Using a 90-day blanking period, primary efficacy endpoint failure is defined as (at least) one episode of atrial arrhythmia with a duration >30 sec (documented by 7-day Holter or 12-lead ECG). Secondary endpoints (Quality-of-Life, rehospitalization, arrhythmia recurrence rate, healthcare utilization, and left atrial function) and adverse events will also be evaluated. Study enrollment will include 218 patients in up to 16 centers., Conclusions: This study will be a multi-national randomized controlled trial comparing cryoablation against AAD as a first-line treatment in patients with paroxysmal AF. The results may help guide the selection of patients for early AF disease therapy via cryoballoon ablation., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: There are no data concerning clinical outcome and left atrial (LA) function after LA roof ablation using a second-generation cryoballoon (CB) for treatment of persistent atrial fibrillation (AF). Here, we report the first follow-up results after pulmonary vein isolation (PVI) plus LA roof ablation with the CB technique in patients with symptomatic persistent AF., Methods and Results: We enrolled 107 consecutive patients who underwent CB ablation at our institution with the aim of PVI and bidirectional conduction block across the LA roof. Clinical success was defined as freedom from >30-s recurrence of AF, atrial flutter, or atrial tachycardia after a 3-month blanking period. Follow-up data were collected during outpatient clinic visits. LA volume, LA emptying fraction, and LA expansion index (parameters of LA function) were evaluated by echocardiography before and 3 months after ablation. PVI was achieved in all patients, and bidirectional conduction block was verified in 91.6%. Median follow-up duration was 31 (interquartile range 11/44) months. PVI plus LA roof ablation was sufficient to restore and maintain sinus rhythm in 72.9% (n = 78) of patients. The overall complication rate was 1.8%. LA volumes decreased significantly after ablation (P < 0.05), whereas total LA emptying fraction (P = 0.25) and LA expansion index (P = 0.32) were preserved within the 3-month follow-up., Conclusions: LA roof ablation combined with PVI using the CB technique is a safe and effective adjuvant treatment with a promising midterm outcome and preserved LA function 3 months after ablation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aims: To evaluate the effectiveness and safety of cryoballoon ablation (CBA) compared with radiofrequency ablation (RFA) for symptomatic paroxysmal or drug-refractory persistent atrial fibrillation (AF)., Methods and Results: Prospective cluster cohort study in experienced CBA and RFA centres. Primary endpoint was 'atrial arrhythmia recurrence', secondary endpoints were as follows: procedural results, safety, and clinical course. A total of 4189 patients were included: CBA 2329 (55.6%) and RFA 1860 (44.4%). Cryoballoon ablation population was younger, with fewer comorbidities. Procedure time was longer in the RFA group (P = 0.01). Radiation exposure was 2487 (CBA) and 1792 cGycm2 (RFA) (P < 0.001). Follow-up duration was 441 (CBA) and 511 days (RFA) (P < 0.0001). Primary endpoint occurred in 30.7% (CBA) and 39.4% patients (RFA) [adjusted hazard ratio (adjHR) 0.85, 95% confidence interval (CI) 0.70-1.04; P = 0.12). In paroxysmal AF, CBA resulted in a lower risk of recurrence (adjHR 0.80, 95% CI 0.64-0.99; P = 0.047). In persistent AF, the primary outcome was not different between groups. Major adverse cardiovascular and cerebrovascular event rates were 1.0% (CBA) and 2.8% (RFA) (adjHR 0.53, 95% CI 0.26-1.10; P = 0.088). Re-ablations (adjHR 0.46, 95% CI 0.34-0.61; P < 0.0001) and adverse events during follow-up (adjHR 0.64, 95% CI 0.48-0.88; P = 0.005) were less common after CBA. Higher rehospitalization rates with RFA were caused by re-ablations., Conclusions: The primary endpoint did not differ between CBA and RFA. Cryoballoon ablation was completed rapidly; the radiation exposure was greater. Rehospitalization due to re-ablations and adverse events during follow-up were observed significantly less frequently after CBA than after RFA. Subgroup analysis suggested a lower risk of recurrence after CBA in paroxysmal AF., Trial Registration: ClinicalTrials.gov (NCT01360008), https://clinicaltrials.gov/ct2/show/NCT01360008., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: Stroke is one of the most feared complications during catheter ablation of atrial fibrillation (AF). While symptomatic thromboembolic events are rare, magnetic resonance imaging (MRI) may identify asymptomatic (ie, silent) cerebral lesions (SCLs) following pulmonary vein isolation (PVI) procedures., Methods and Results: The REDUCE-TE Pilot was a prospective multicenter, single-arm observational study investigating the incidence of SCL in patients with symptomatic paroxysmal AF undergoing PVI with a novel gold-tip, externally irrigated ablation catheter. After ablation, cerebral diffusion-weighted MRI and a postablation follow-up were performed at 1 to 3 days after the ablation procedure. A neurocognitive test was done before and after ablation. The primary study endpoint was the occurrence of one or more new SCLs. Secondary study endpoints included neurocognitive status, procedural success rate, and periprocedural complications including symptomatic thromboembolic events. A total of 104 patients were enrolled (69% male, mean age: 61.5 ± 9.7 years, mean CHA 2 DS 2 -VASc score: 1.7 ± 1.2). Postprocedural MRI examination was performed in 97 patients, and in nine of them (9.3%; 95% CI: 4.3-16.9%) a total of 11 SCLs were detected. Univariate analyses did not reveal any significant predictor for new SCLs. Nonsignificant trends were observed for low activated clotting time during ablation and for international normalized ratio value outside the range of 2 to 3 at ablation. There was no evidence of significant deterioration of neurocognitive function after PVI. In four patients, a pericardial tamponade was noted but all patients fully recovered during follow-up., Conclusions: Ablation of AF using a novel gold-tip, externally irrigated ablation catheter, resulted in SCLs in approximately one out of 10 patients without a measurable effect on neurocognitive function., (© 2019 The Authors. Journal of Cardiovascular Electrophysiology Published by Wiley Periodicals, Inc.)

Background: Robotic (RNS) or magnetic navigation systems (MNS) are available for remotely performed catheter ablation for atrial fibrillation (AF)., Objective: The present study compares remotely assisted catheter navigation (RAN) to standard manual navigation (SMN) and both systems amongst each other., Methods: The analysis is based on a sub-cohort enrolled by five hospitals from the multicenter German ablation Registry., Results: Out of 2442 patients receiving catheter ablation of AF, 267 (age 61.4 ± 10.4, 69.7% male) were treated using RAN (RNS n = 187, 7.7% vs. MNS n = 80, 3.3%). Fluoroscopy time [RNS median 17 (IQR 12-25) min vs. MNS 22 (16-32) min; p < 0.001] and procedure duration [RNS 180 (145-220) min vs. MNS 265 (210-305) min; p < 0.001] were significantly different. Comparing RAN (11%) to SMN (89%) fluoroscopy time (RAN 19 (13-27) min, vs. SMN 25 (16-40) min; p < 0.001), energy delivery (RAN 3168 (2280-3840) s vs. SMN 2640 (IQR 1799-3900) s; p = 0.008) and procedure duration [RAN 195 (150-255) min vs. SMN 150 (120-150) min; p = 0.001] differed significantly. In terms of acute and 12 months outcome, no differences were seen between the two systems or in comparison to SMN., Conclusion: AF ablation can be performed safely, with high acute success rates using RAN. RNS results in less fluoroscopy burden and shorter procedure durations. Compared to SMN, a reduced fluoroscopy burden, prolonged procedure and ablation duration were observed using RAN. Overall, the number of RAN procedures is small suggesting low impact on clinical routine of AF ablation.

Introduction: We analyzed the procedural experience and clinical outcome after pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF) gained over 5 years using the second-generation cryoballoon (CB-Adv)., Methods and Results: For this retrospective study, we enrolled 281 patients undergoing PVI at our institution between 2012 and 2016. The analyzed period was divided into 5 calendar years. Follow-up data, including Holter electrocardiography recordings, were collected during outpatient clinic visits. The impact of several variables on outcome was evaluated by means of univariate and multivariate analyses and Cox proportional hazards regression models. The median procedure and fluoroscopy times over the years were 90 (72 of 114) and 15 (11 of 21) minutes, respectively. A continuous decline in complication rates and fluoroscopy and procedure times was observed in each subsequent year. During mid-term follow-up (33 [25 of 48] months), 178 (63.3%) patients were AF, atrial flutter, or atrial tachycardia free. Multivariate analysis revealed left atrial area (hazard ratio [HR] = 1.05; P < 0.001), female sex (HR = 2.53; P < 0.001), and common ostium (HR = 1.93; P < 0.001) as significant predictors of outcome. The overall 1-year success rate was 76.2%. A gradual decrease in the 1-year success rate (from 90.5% in 2012 to 67.9% in 2016) was mainly related to a steady increase of left atrial area in the entire cohort with successive years of the study., Conclusions: PVI using CB-Adv in patients with persistent AF is accompanied by a learning curve and facilitates a satisfactory outcome, followed by the proper selection of patients., (© 2018 Wiley Periodicals, Inc.)

Aims: Predictors of atrial arrhythmia recurrence have not been described in a long-term follow-up study of patients undergoing pulmonary vein isolation (PVI) using the cryoballoon technique. We aimed to evaluate the efficacy of a second-generation cryoballoon and identify pre-procedural predictors of 3-year outcome after PVI., Methods and Results: For this observational cohort study, we enrolled 440 patients ablated at our institution with a second-generation cryoballoon. The endpoint was the first documented recurrence (>30 s) of atrial fibrillation (AF), atrial flutter, or atrial tachycardia after a 3-month blanking period. The impact of several pre-existing variables on clinical outcome was evaluated by univariate and multivariate analyses using the Cox proportional hazards regression model. The PLAAF (persistent AF, left atrial area, abnormal PV anatomy, AF history, female gender) score was defined to predict outcome. After a median follow-up of 36 months (interquartile range 25/75-27/42), the endpoint was achieved in 95 of 440 (21.6%) patients. Cox regression analysis showed that persistent AF, left atrial (LA) area, abnormal PV anatomy, AF history, and female gender independently predicted recurrence. The calculated optimal cut-offs for LA area and AF history were 21 cm2 and 3 years, respectively. Patients with a PLAAF score of 0 showed the best outcome, with an arrhythmia-free survival of 86.7%., Conclusion: PVI using the cryoballoon technique shows acceptable long-term results depending on predictors described by the new PLAAF score, which may facilitate patient selection for PVI.

Introduction: Data on long-term outcomes of cryoballoon ablation for treatment of atrial fibrillation (AF) are sparse. Here, we report the first 5-year follow-up results and predictors of outcome for pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB-Adv) in patients with symptomatic AF., Methods and Results: For this prospective observational study, we enrolled 178 patients with paroxysmal (132/178 [74.2%] patients) or persistent AF who underwent PVI with CB-Adv at our institution during 2012. Clinical success was defined as freedom from AF, atrial flutter or atrial tachycardia recurrence >30-s following the 3-month blanking period. Follow-up data were collected during outpatient clinic visits and included Holter-ECG recordings. The impacts of several variables on outcome were evaluated by means of univariate and multivariate analyses and Cox proportional hazards regression models. PVI was sufficient in restoring and maintaining sinus rhythm in 59.0% (n = 105) of patients (paroxysmal AF: 81/132 (61.4%) patients; persistent AF: 24/46 (52.2%) patients, P = 0.20). The median procedure and fluoroscopy times were 126 (interquartile range 114/150) and 20 (16/26) min, respectively. Cox regression analysis showed that left atrial area ≤21 cm 2 and the absence of diabetes independently predicted outcome., Conclusions: Sinus rhythm was maintained in a substantial proportion of patients even 5 years after CB-Adv ablation. Patients with a non-enlarged left atrium without diabetes had the best outcome., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Antiarrhythmic drug (AAD) therapy of patients with atrial fibrillation (AF) has limitations. We investigated the 2-year outcome and pre-procedural predictors of recurrence for first-line catheter ablation using the second-generation cryoballoon (CB-Adv) in a large cohort of patients with symptomatic AF., Methods and Results: For this prospective observational study, we enrolled 457 patients with symptomatic AF (278 paroxysmal, 179 persistent) who had no history of AAD use and who underwent pulmonary vein isolation (PVI) with the CB-Adv at our institution. Follow-up data, including Holter-ECGs, were collected during outpatient clinic visits. The impact of several variables on outcome was evaluated in univariate and multivariate analyses and Cox proportional hazards regression models. Median follow-up duration was 28 (interquartile range 15/42) months. PVI was sufficient in restoring and maintaining sinus rhythm in 79.2% (n=362) of patients. The median procedure and fluoroscopy times were 90 (72/120) and 16 (12/21) min, respectively. Phrenic nerve injury occurred in 16 (3.5%) patients, persisting until hospital discharge in 6 (1.3%) patients; phrenic nerve function recovered in all patients during follow-up. Seven patients developed groin hematomas (1.5%). Cox regression analysis showed that left atrial area >21cm 2 independently predicted recurrence., Conclusion: This is the first demonstration that PVI with CB-Adv is safe and effective as a first-line treatment of symptomatic AF. Sinus rhythm persisted in 79.2% of patients even 2years after ablation. The success rate was lower in patients with enlarged left atria., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: We aimed to compare arrhythmia recurrence rates after second-generation cryoballoon (CB-Adv) ablation and radiofrequency (RF) ablation in patients with symptomatic persistent atrial fibrillation (AF) and left atrial (LA) enlargement., Methods and Results: Persistent AF patients with LA enlargement were compared using a propensity-score-matching algorithm, and 111 patients treated with CB-Adv ablation and 111 patients treated with RF ablation were selected. The primary endpoint was the first documented >30-second arrhythmia recurrence after a 3-month blanking period. Median LA area was comparable between the RF and CB-Adv groups (24.2 vs. 24.0 cm 2 , P = 0.49). In addition to pulmonary vein isolation, roof lines (RLs) with bidirectional conduction block were created in 48 patients in the CB-Adv group and 49 patients in the RF group. Midterm outcome after single procedure is characterized by arrhythmia recurrences in 47 patients in the RF group and 32 patients in the CB-Adv group (P = 0.20). There were no differences in the number of AF recurrences in the two groups (38 vs. 32, P = 0.66), but there were more instances of LA tachycardia (LAT) in the RF group than in the CB-Adv group (11 vs. 0, P < 0.01). LAT recurrence in RF patients was associated with RL creation (9 with vs. 2 without, P < 0.01). Among patients in whom a RL was created, arrhythmia-free survival was lower in the RF group than in the CB-Adv group (44.9% vs. 79.2%, P < 0.01)., Conclusions: Arrhythmia recurrence rates in the two groups during midterm follow-up were comparable. RL creation during CB-Adv ablation resulted in acceptable outcomes., (© 2017 Wiley Periodicals, Inc.)

Introduction: Data on long-term outcomes of cryoballoon (CB) ablation for treatment of persistent atrial fibrillation (AF) are sparse. Here, we report the first 3-year follow-up results and predictors of success for catheter ablation using the second-generation CB in patients with persistent AF., Methods and Results: For this prospective observational study, we enrolled 101 patients ablated with the second-generation CB at our institution. The endpoint was the first documented recurrence (> 30 seconds) of AF, atrial flutter, or atrial tachycardia after a 3-month blanking period. Follow-up data were collected during outpatient clinic visits and included Holter-ECG recordings. The impact of several variables on recurrence was evaluated by means of univariate and multivariate analyses and Cox proportional hazards regression models. After a median follow-up of 37 (31 of 42) months, recurrence was documented in 30 patients (29.7%). The median procedure and fluoroscopy times were 120 (102 of 147) and 20 (16 of 27) minutes, respectively. Phrenic nerve palsy occurred in 2.0% of the patients. Among the 30 patients who experienced recurrence, 16 underwent repeat ablation in radiofrequency technique. Cox regression analysis showed that left atrial area > 21 cm 2 and AF history duration > 2 years independently predicted recurrence., Conclusions: Sinus rhythm was maintained in a substantial proportion of patients even 3 years after CB ablation. Patients with a nonenlarged left atrium and short AF history had the best outcome., (© 2017 Wiley Periodicals, Inc.)

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., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

Aims: Although the generation of linear lesions by ablation improves success rates in patients with persistent atrial fibrillation (AF), the procedure has been considered unsuitable for cryoablation balloon catheter technologies. We developed a technique for linear ablations, using second-generation cryoballoon technology., Methods and Results: This was a single-arm, prospective study in 76 patients with persistent AF treated consecutively at our centre. Cryoablation was performed using a 28 mm second-generation cryoballoon. The first cryoenergy application was performed in close proximity to the position during isolation of the left superior pulmonary vein (PV). Sequential overlapping freezes were applied along the left atrial (LA) roof by slight clockwise rotation of the sheath in combination with slight retraction of the sheath and incremental advancement of the cryoballoon, until reaching the original position for right superior PV isolation. The acute endpoint was the creation of a roofline, defined as complete conduction block across the LA roof >120 ms and ascending activation across the posterior LA wall. Acute success in roofline generation was achieved in 88% of patients, applying on average five (median 4-6) freezes with nadir temperature of -40°C (-36 to -44°C). In five patients, conduction block could not be achieved. No phrenic nerve injuries occurred during roofline generation., Conclusion: Generation of linear roofline lesions is possible with the second-generation cryoballoon. The technique can be used in combination with PV isolation to treat persistent AF with good acute success rates, short procedure times, and acceptable safety concerns. If validated by further studies, the method would be an appealing alternative to radiofrequency ablation techniques., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

Background: Although radiofrequency (RF) ablation has long been the standard of care for atrial fibrillation (AF) ablation, cryoballoon technology has emerged as a feasible approach with promising results. Prospective multicenter registry data referring to both ablation technologies in AF ablation are lacking so far., Objective: The purpose of this study was to report data from the German ablation registry with respect to efficacy and safety in pulmonary vein ablation with different energy sources for paroxysmal AF after 1-year follow-up., Methods: A total of 2306 patients with symptomatic paroxysmal AF from the German ablation registry were included in this analysis. The cohort was divided into two groups according to the ablation energy source used: cryoballoon and RF ablation. MACCE was defined as a combination of death, myocardial infarction, or stroke., Results: AF recurrence rate after a single ablation procedure at 1 year follow-up was not significantly different between the two groups (45.8% after cryoablation and 45.4% after RF ablation, P = .87). Also, the rate of patients without AF recurrence and free of antiarrhythmic drug at 12-month follow-up was similar (cryoablation 44.2% and RF 41.4%, P = .25). MACCE occurred with an incidence of 0.7% within 500 days after cryoablation and 1.4% after RF ablation (P = .30). Persistent phrenic nerve palsy was more common after cryoablation compared to RF ablation (1.1% vs. 0.3%, P <.05)., Conclusion: AF recurrence rate at 1-year follow-up was similar in RF ablation compared to cryoablation, whereas the spectrum and relevance of complications were significantly different between the two ablation methods. This finding might influence the choice of ablation method offered to the individual paroxysmal AF patient., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: First-line ablation prior to antiarrhythmic drug (AAD) therapy is an option for symptomatic paroxysmal atrial fibrillation (PAF); however, the optimal ablation technique, radiofrequency (RF), or cryoballoon (CB) has to be determined., Methods and Results: The FREEZE Cohort Study compares RF and CB ablation. Treatment-naïve patients were documented in the FREEZEplus Registry. Periprocedural data and outcome were analysed. From 2011 to 2014, a total of 373/4184 (8.9%) patients with PAF naïve to AAD were identified. Pulmonary vein isolation (PVI) was performed with RF (n = 180) or CB (n = 193). In the RF group, patients were older (65 vs. 61 years, P < 0.01) compared with the CB group. The procedure time was significantly shorter and radiation exposure higher in the CB group. Major adverse events occurred in 1.6% (CB) and 3.7% (RF) of patients (P = 0.22). AF/atrial tachycardia (AT) recurrence until discharge was 4.5% (RF) and 8.5% (CB, P = 0.2). Follow-up (FU) ≥12 months was available in 99 (RF) and 107 (CB) patients. After 1.4 years of FU, freedom from AF/atrial tachycardia (AT) was 61% (RF) and 71% (CB, P = 0.11). In the RF group, more patients underwent cardioversion, and a trend for more repeat ablations was observed. Persistent phrenic nerve palsy was observed in one patient treated by CB., Conclusion: First-line ablation for PAF is safe and effective with either RF or CB. The procedure was faster with the CB, but the radiation exposure was higher. Although there was a trend for more recurrences and complications in the RF group, a more favourable risk profile in patients undergoing CB ablation might have biased the results., Clinicaltrialsgov Identifier: NCT01360008., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Aims: In this observational study, we examine the significance of the left atrial (LA) surface area and compare the clinical usage of the Arctic Front Advance (CBA) versus Arctic Front (CB) cryoballoon with the intent to investigate the impact of each in terms of long-term freedom from atrial fibrillation (AF) for patients with nonvalvular AF., Methods: Pulmonary vein isolation (PVI) was performed while using a cryoballoon ablation catheter in conjunction with an intraluminal circular diagnostic mapping catheter, Achieve. The consecutive patients ablated with CBA were matched with patients previously ablated with CB, using propensity score matching. The primary endpoint of this observational single-center retrospective study was the first observation of electrocardiogram-documented recurrence of atrial arrhythmias lasting >30 seconds., Results: The patient demographic data were similar in the CBA- and CB-group (N = 188 patients each group). In all patients in the CBA-group and in 95% of the patients in the CB group, acute procedural PVI of all veins was achieved with the single usage of a 28-mm cryoballoon. The one-year freedom from atrial arrhythmias was significantly better in the CBA- versus the CB-group of patients, 90% versus 64%, respectively. During 15-month clinical follow-up in CBA group, patients with LA area above 23 cm(2) were more likely to experience recurrence of AF (23%) than patients with LA area below 23 cm(2) (7%)., Conclusions: Comparing one-year outcomes, the CBA is superior to the CB with regards to maintenance of normal sinus rhythm. When using the CBA catheter, an enlarged LA is associated with a higher recurrence of arrhythmia., (© 2015 Wiley Periodicals, Inc.)

Background: The aim of the study was identification of the predictors of left atrial tachycardia and left atrial flutter (LATAFL) after radiofrequency catheter ablation of atrial fibrillation (CAAF)., Methods: We followed 598 patients (71% male, 41% paroxysmal AF; median follow-up: 36 months) after a single step-wise CAAF procedure. The time to first documented LATAFL lasting longer than 30 s, documented in any kind of electrocardiography (ECG), was defined as an end-point., Results: A single CAAF procedure resulted in LATAF in 58 (10%) patients. Additional lesions were performed in 275 (46%) patients. Early LATAFL recurrence (£ 3 months since the index procedure) was observed in 11 (2%) patients. Late LATAFL (> 3 months) was noted in 47 (8%) patients. The univariate predictors of LATAFL recurrence were: type of AF (p = 0.003), the size of LA (p = 0.002) and the type of procedure (p = 0.0001). The identified single independent predictors of LATAFL recurrence were enlarged LA (p = 0.001) and mul-tiple (≥ 2) additional lesions performed during the index procedure (p < 0.0001)., Conclusions: Higher rate of LATAFL recurrence was observed in patients with non-paroxysmal AF, enlarged LA and any additional lesions performed. Two independent predictors of LATAFL recurrence after CAAF were: the enlarged LA and multiple (≥ 2) additional lesions performed during the index procedure.

Background: Relation between pre-procedural selection of patients and the success rate after a single cryoballoon ablation (CAB) procedure is unknown., Methods: CAB was performed in 378 (65% male, median age 58 years, 85% paroxysmal atrial fibrillation [AF]) consecutive patients with symptomatic and drug refractory AF. The combined ALARMEc (Atrial fibrillation type, Left Atrium size, Renal insufficiency, Metabolic syndrome, cardiomyopathy) risk score was calculated for each individual patient. The end-point of the study was the first AF, atrial flutter or atrial tachycardia recurrence after the 3-month blanking period in the 1-year follow-up since the index procedure, in the absence of anti-arrhythmic (class I and III) therapy., Results: Single and multi-catheter approach was used in 79% and 21% of patients, respectively. The acute success rate with single and multi-catheter approach was 79% and 99%, respectively. The overall 1-year success rate after a single CAB procedure was 70%. The 1-year outcome was: 83%, 70%, 60%, 40% and 29% in patients with ALARMEc risk score: 0, 1, 2, 3 and 5, respectively. Total rate of complications was 11%, including transient phrenic nerve palsy in 9.5% of cases., Conclusions: Multi-catheter approach was needed in 21% of patients to achieve acute pulmonary vein isolation. Patients with low (≤ 1) ALARMEc risk score, preferably young individuals with sole paroxysmal AF (ALARMEc = 0), are best candidates for CBA procedure. Performing CBA in patients with higher (> 2) ALARMEc risk score should be avoided. Phrenic nerve palsy was a transient complication.

Aims: Cryoballoon (CB) ablation with the second-generation cryoballoon (CBG2) seems to be more effective than its predecessor [first-generation cryoballoon (CBG1)], but phrenic nerve palsies were observed more frequently. The aim of this study was to compare the safety and efficacy of CBG1 and CBG2 in a substudy of the prospective multicentre, multinational FREEZE Cohort Study., Methods and Results: Periprocedural data were analysed, and a total of 532 patients with paroxysmal atrial fibrillation (AF) were examined (n = 224 for CBG1 and n = 308 for CBG2). Procedure time decreased significantly from 149 to 130 min when comparing CBG1 with CBG2 (P < 0.0001), and pulmonary vein isolation (PVI) was achieved in 97.8 and 97.6% of PVs with CBG1 and CBG2 (P = 0.77), respectively. The need for dual-balloon usage within a procedure dropped (20.1 vs. 9.0%, P < 0.001), and the fluoroscopy time was reduced when operating the CBG2. Atrial fibrillation recurrence rates until discharge were similar (5.0 vs. 5.8%, P = 0.69). Comparable low rates of major complications were observed with both CBs, and there was a non-significant trend for more phrenic nerve palsies., Conclusion: Second-generation cryoballoon demonstrated a high rate of acute PVI in a significant faster procedure, which also utilized less radiation exposure and less dual-balloon usage during an average procedure. The safety profile remains favourable with a non-significant trend for more phrenic nerve palsies. If the enhancements lead to a higher clinical benefit has to be determined. The 1-year outcome data from the ongoing FREEZE Cohort Study comparing radiofrequency and CB ablation will shed some light on that issue., Clinical Trials Gov Identifier: NCT01360008., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)

Introduction and Objectives: Long-term efficacy following cryoballoon ablation of lone paroxysmal atrial fibrillation remains unknown. We describe long-term follow-up results of the single cryoballoon ablation procedure., Methods: Pulmonary vein isolation was performed in 103 patients (72 male; median age 52 years) with symptomatic lone paroxysmal atrial fibrillation. The end-point of this observational cohort study was first electrocardiogram-documented recurrence of arrhythmia (atrial fibrillation, atrial tachycardia, or atrial flutter) during the 5-year follow-up, in the absence of anti-arrhythmic treatment., Results: Acute complete pulmonary vein isolation was achieved in 86% of the patients with a single cryoballoon. The 6-month, 1-year, and 5-year success rate after a single procedure was 94%, 91%, and 77%, respectively. Arrhythmia recurrence was observed in 24 cases at a median of 14.8 months [range, 8.0-16.8 months]. Thirteen symptomatic patients were well controlled on beta-blockers only. Seven symptomatic patients had anti-arrhythmic treatment (class IC in 5 patients; dronedarone in 2 patients) introduced during the blanking period. Two of them had early arrhythmia recurrence within the blanking period only; they were arrhythmia-free in further follow-up on dronedarone. The rate of complications was relatively low and included a 4.8% incidence of transient phrenic nerve palsy., Conclusions: A single cryoballoon ablation procedure for lone paroxysmal atrial fibrillation resulted in high rates of acute, medium-term, and long-term efficacy. The rate of complications is relatively low and includes a 4.8% incidence of transient phrenic nerve palsy., (Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.)

Background: Catheter ablation (CA) of atrial fibrillation (AF) is now established therapeutic option. Multiple procedures (MPs) are often needed to achieve the satisfactory outcome. The aim of the study was to assess the outcome after MPs in AF patients categorized to risk-score groups., Methods: We followed a cohort of consecutive 911 (69% male; median 59 years) patients with AF (58% paroxysmal) who had CAAF performed. ALARMEC (Atrial fibrillation type, Left Atrium size, Renal insufficiency, MEtabolic syndrome, cardiomyopathy) risk score was calculated for each patient. The end point was maintenance of sinus rhythm at the follow-up of 60 months., Results: We performed 1,199 CAAF procedures. One, two, and three procedures were performed in 663 (73%), 208 (23%), and 40 (4%) patients, respectively. Outcome after the first procedure (56%) was improved with MPs (76%). MPs > 2 were performed in 1%, 3%, 5%, 6%, and 10% patients with ALARMEC score of 0, 1, 2, 3, and 4, respectively. MPs were successful in 89%, 86%, 81%, 65%, and 43% of patients with ALARMEC score of 0, 1, 2, 3, and 4, respectively. Outcome in 174 (19%) patients on antiarrhythmic drugs (AADs) was 85%, 68%, 75%, 44%, and 39% in ALARMEC score: 0, 1, 2, 3, and 4, respectively. Outcome in 737 (81%) patients without AAD was 90%, 85%, 80%, 77%, and 69% in ALARMEC score of 0, 1, 2, 3, and 4, respectively., Conclusion: The moderate success rate after index procedure of CAAF can be further improved with multiple ones and AAD., (©2014 Wiley Periodicals, Inc.)

Background: Catheter ablation is used extensively with curative intention in atrial fibrillation. Radiofrequency ablation has long been a standard of care, while cryoballoon technology has emerged as a feasible approach with promising results. Prospective multicenter registry data referring to both ablation technologies in AF ablation therapy are lacking., Methods: Between January 2007 and August 2011, a total of 3,775 consecutive patients with symptomatic paroxysmal AF who underwent PV ablation in their respective centers were enrolled. The cohort was divided into 2 groups according to the ablation energy source used: cryoballoon ablation (group 1, n = 905 [24.0%], median age 63 years, 64.3% men) and RF ablation (group 2, n = 2870 [76.0%], median age 63 years, 62.7% men). Comorbidities and baseline clinical characteristics were similar in both groups., Results: Acute success rate was similar in both groups (97.5% in cryo vs 97.6% in RF; P = 0.81). Procedure times were similar, ablation and fluoroscopy times were higher in cryoballoon when compared to RF ablation. Overall complication rate was similar in cryo- (4.6%) and RF-ablation (4.6%; P = 1.0). Phrenic nerve palsy was more often in cryo versus RF ablation (2.1% in cryo vs 0.0% in RF; P < 0.001). Other complications were more common in RF compared to cryoablation (4.6% in RF vs 2.7% in cryo; P < 0.05)., Conclusion: RF ablation is the most widespread ablation method in Germany, but use of cryoballoon increased significantly. Procedure times were similar, but ablation and fluoroscopy times were longer in cryoballoon ablation. No significant differences were found in terms of acute success and overall complication rate., (© 2014 Wiley Periodicals, Inc.)

Background: We analyzed the procedural experience cryoballoon ablation (CBA) of atrial fibrillation (AF) gained over 8 years in a high-volume centre to understand the influence of the learning curve on feasibility, safety and clinical outcome., Methods and Results: In 424 patients (62% male) with drug-refractory AF, CBA was performed between 2005 and 2012. The analyzed period was divided into 8 calendar years. The endpoint of the study was arrhythmia recurrence after the 3-month blanking period in the 1-year follow-up since the index procedure, in the absence of anti-arrhythmic drugs class I and III. A combined AF type, Left Atrium size, Renal insufficiency, MEtabolic syndrome, cardiomyopathy (ALARMEc) risk score was calculated for each patient. The overall 1-year success rate of a single CBA was 73%. Continuous increase in 1-year success rate was observed with successive years of the study. The gradual improvement in outcome was related to gradual fall in ALARMEc risk score in successive patients. A continuous decrease in fluoroscopy and procedure time was observed in each subsequent year., Conclusions: CBA, followed by the proper selection of patients, facilitates a satisfactory outcome, especially in patients at an early stage of PV-trigger-dependent AF. Still, as with each new technology, it requires completion of a learning curve.

Aims: Long-term efficacy following cryoballoon (CB) ablation of atrial fibrillation (AF) remains unknown. This study describes 5 years follow-up results and predictors of success of CB ablation in patients with paroxysmal atrial fibrillation (PAF)., Methods and Results: In total, 163 patients were enrolled with symptomatic, drug refractory PAF. Pulmonary vein isolation (PVI) with CB technique was performed. Primary endpoint of this consecutive single-centre study was first electrocardiogram-documented recurrence of AF, atrial tachycardia or atrial flutter (AFLAT). Five years success rate after single CB ablation was 53%. In 70% of the patients acute complete PVI was achieved with a single 28 mm balloon. The univariate predictors of AFLAT recurrence were (1) size of left atrium, with normalized left atrium (NLA) ≥10.25 [hazard ratios (HR) of 1.81, 95% confidence interval (CI): 1.28-2.56] when compared with NLA <10.25 (35% vs. 53%, P = 0.0001) and (2) renal function, with impaired glomerular filtration rate (GFR) <80 ml/min (HR of 1.26, 95% CI: 1.02-1.57) when compared with GFR ≥80 ml/min (45% vs. 53%, P = 0.041). Normalized left atrium ≥10.25 was the sole independent predictor for outcome (HR 2.11; 95% CI: 1.34-3.31; P = 0.0001)., Conclusions: Sinus rhythm can be maintained in a substantial proportion of patients with PAF even 5 years after circumferential PVI using CB ablation. The rate of decline in freedom from AFLAT was highest within the first 12 months after the index procedure. The patients with enlarged left atrium and/or impaired renal function have lower outcome.

Background: Predictors of long-term outcome of atrial fibrillation (AF) ablation are unknown. The predictors of 5-year follow-up (FU) after single ipsilateral circumferential antrum pulmonary vein isolation (PVI) with irrigated tip catheter were investigated., Methods and Results: In 356 patients (74% male) with AF (44% paroxysmal AF [PAF]) PVI was performed. Success was defined as absence of AF, atrial flutter or tachycardia (AFLAT) recurrence. A total of 161 patients (45%) were free of AFLAT. The univariate predictors of AFLAT recurrence were: type of AF (non-PAF vs. PAF, P=0.0001), size of LA (normalized left atrium area [NLA] ≥11.5 vs. NLA <11.5, P=0.0001), renal function (glomerular filtration rate [GFR] <68ml/min vs. GFR ≥68ml/min, P=0.001) and hypertension (HT vs. no HT, P=0.025). The independent predictors of AFLAT-free survival were non-PAF (hazard ratio [HR], 1.67; 95% confidence interval [CI]: 1.23-2.26, P=0.0005), NLA ≥11.5 (HR, 1.40; 95% CI: 1.03-1.90, P=0.007) and GFR <68ml/min (HR, 1.70; 95% CI: 1.21-2.37, P=0.008)., Conclusions: Single PVI results in a moderate success rate in patients with AF during 5-year FU without the use of a 3-D mapping system. Higher success was observed in patients with PAF, non-enlarged LA and good renal function.

Background: Pre-procedural predictors (PP) of atrial fibrillation (AF) recurrence (AFR) after repeated catheter ablation of AF (RCAF) are unknown. The aim of this study was identification of PP of outcome after RCAF., Methods and Results: In 213 patients (73% male) with drug-refractory AF (47% paroxysmal AF; PAF) RCAF was performed. CHADS2, CHA2DS2-VASc and ALARMEc (AF type, Left Atrium size, Renal insufficiency, MEtabolic syndrome, cardiomyopathy) scores were calculated for each patient. Complete success was defined as no AFR. After RCAF, 125 patients (59%) were free of atrial flutter or atrial tachycardia (AFLAT) on long-term follow-up (FU). The univariate predictors of AFR were: type of AF (non-PAF vs. PAF, P=0.001), normalized left atrium area (NLA ≥10.25 vs. NLA <10.25, P=0.012) and estimated glomerular filtration rate (<68ml/min vs. ≥68ml/min, P=0.048). The independent predictors of AFLAT-free survival after RCAF were non-PAF (P=0.002) and NLA ≥10.25 (P=0.018). Among combined predictors, only ALARMEc score, and neither CHADS2 or CHA2DS2-VASc, predicted outcome after RCAF (P<0.0001)., Conclusions: RCAF results in a moderate success rate on very long-term FU. Lower success was observed in patients with non-PAF and enlarged LA. ALARMEc score allows for clear description of expected outcome after RCAF.

Aims: Cryoballoon (CB) ablation has proven very effective in achieving pulmonary vein isolation (PVI). The Achieve catheter (AC) is a novel inner lumen catheter designed to be used in conjunction with the CB, which serves the double purpose of a guidewire and a mapping catheter. We aimed to evaluate the feasibility of CB ablation in conjunction with the novel AC, in terms of PVI and safety in a series of patients affected by drug resistant paroxysmal atrial fibrillation (AF)., Methods and Results: Seventy patients (49 male) affected by paroxysmal AF were assigned to CB PVI using the AC as a mapping catheter. Patients underwent loop-Holter monitoring 1, 3 and 6 months after ablation. Isolation occurred in 98% of PVs with the CB-AC association without having switching to a regular guidewire. Pulmonary vein isolation could be documented by real-time (RT) recordings in 47% (132) of veins. Time to isolation was significantly longer in PVs exhibiting early left atrium-PV reconnection if compared with veins with sustained isolation (117 ± 25 s vs. 59 ± 25 s; P< 0,005). No serious complications occurred; four transient phrenic nerve palsies occurred all resolving completely before the end of the procedure., Conclusion: Cryoballoon ablation in conjunction with the novel AC is feasible, safe, and most importantly affords PVI in nearly all veins without having to switch to a regular guidewire. However, RT recordings could be documented in only 47% of pulmonary veins.

Background: The goal of this study was to analyze impact of metabolic syndrome (MetS) and impaired renal function on long-term follow-up after catheter ablation of atrial fibrillation (AF)., Methods and Results: A total of 702 consecutive patients with AF (age = 58 year, history of AF = 5 year, male = 478, paroxysmal atrial fibrillation = 416, coronary artery disease = 62, hypertension = 487) considered for catheter ablation were enrolled in the study. The MetS was diagnosed at admission in 276 patients. The renal function was estimated by glomerular filtration rate (eGFR). Pulmonary vein isolation (PVI) was performed either with cryoballoon technique (n = 260) or circumferential PVI (n = 442) with a 3.5-mm irrigated tip catheter. A 7-day-Holter electrocardiogram was performed at each follow-up visit. Any episode of documented AF after an initial 3-month blanking period was considered as clinical endpoint. Out of 702 patients, 370 (52.7%) were free of AF recurrences at median follow-up of 15 six interquartile range (12.7-42.3) months. The patients with MetS had significantly lower success rate than those without (128/276 (46.4%) vs 242/426 (56.8%), P = 0.006). Among 103 patients with eGFR < 68 mL/min only 35 (34%) were free of recurrences compared with 335/599 (55.9%) in patients with GFR ≥ 68 mL/min (P = 0.001). Both parameters were revealed in multivariate analysis to be independent predictors for outcome after catheter ablation., Conclusion: The results of our study clearly demonstrated that outcome after 1st catheter ablation of AF is poor in patients with MetS and/or impaired renal function. This observation has a potential clinical impact for the follow up management of these patients., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)

Background: Radiofrequency (RF) current is used as a common energy source to perform pulmonary vein isolation (PVI) in patients with atrial fibrillation. We applied measurements of the blood concentration of cTnI as a surrogate parameter for the injured cell mass., Aim: To clarify which parameters are major determinants of myocardial injury, estimated by cTnI, after PVI with RF ablation., Methods: The study population consisted of 82 consecutive patients in whom PVI with RF ablation was performed. In 41 patients, additional linear lesions (LL) were needed. Blood samples were obtained during venous puncture before a procedure and a further one, six and 24 hours after ablation., Results: Pathological cTnI values were observed in all patients in the first hour and further increased in time. The median of peak cTnI value in the LL group was significantly (p 〈 0.05) higher than the respective value in patients without LL made: 1.16 (0.85;1.98) and 0.94 (0.65;1.14) ng/mL, respectively. Significantly higher cTnI values (p = 0.043) were observed in patients who maintained sinus rhythm in long term follow-up., Conclusions: The only independent predictor of myocardial injury after PVI with RF ablation, expressed as an increase in cTnI level, is cumulative energy applied. The larger the myocardial injury, the greater the PVI effectiveness.

Aims: Cerebral embolism is a possible serious complication during catheter ablation of atrial fibrillation (AF). The purpose of this prospective pilot study was to analyse the incidence and possible impact of cryo ablation on cerebral lesions and possible differences to radiofrequency (RF) ablation during pulmonary vein isolation (PVI)., Methods and Results: Pulmonary vein isolation was performed in 89 patients, either with the cryoballoon technique (n = 45) or with RF ablation (n = 44). Phenprocoumon was stopped 3 days before intervention and replaced by subcutaneous low-molecular-weight heparin. During the catheter procedure, an infusion of unfractionated heparin was maintained to achieve an activated clotting time (ACT) of > 300 s. Cerebral magnetic resonance imaging scans were performed 1 day before and after PVI, and at 3-month follow-up. Chronic lesions were observed in 11 patients (12.3%) before PVI without statistically significant difference between the two groups. None of the patients had neurological symptoms during or following the procedure. Seven patients (7.9%) developed acute lesions 1 day after PVI, without statistically significant difference between the group treated by cryoenergy (8.9%) and RF ablation (6.8%). Patients with acute lesions were significantly older compared with those without acute cerebral lesions. No additional cerebral lesions during follow-up were observed., Conclusion: A considerable portion of patients with AF but without any neurological symptoms had chronic cerebral lesions before PVI. Additional acute lesions could be added after the procedure. Both ablation techniques showed additional cerebral acute lesions with no neurological symptoms after PVI.

Background: Cerebral embolic events represent recognized side effects after catheter ablation in the treatment of recurrent atrial fibrillation (AF)., Objective: The study was performed to analyze the neuropsychological outcome and to detect new embolic ischemic brain lesions after therapeutic left atrial catheter ablation of AF., Methods: We enrolled 23 patients with recurrent AF who underwent elective circumferential pulmonary vein isolation. The primary endpoint was the neuropsychological outcome 3 months after intervention in contrast to the results of non-AF controls (n = 23) without ablation and in covariance of baseline performance. Cerebral diffusion-weighted magnetic resonance imaging (DWI) was performed in 21 AF patients at baseline, 2-4 days, and 3 months after intervention., Results: In 3/21 patients (14.3%), new ischemic lesions were detected on DWI shortly after intervention. In one patient, a territorial middle cerebral artery infarct occurred with severe clinical symptoms. The other two patients represented clinically silent small lesions. In contrast to the control group and in covariance of baseline performance, the ablation group showed worse neuropsychological outcome in verbal memory (one of five cognitive domains) with an effect size of d = 0.93[t (.05; 42) = -3.53; P < .001; false discovery rate (FDR)(crit) ≤ .01]., Conclusion: Adverse neuropsychological changes after left atrial catheter ablation are verifiable in verbal memory and, conjoined with ischemic brain lesions on DWI, might represent cerebral side effects of this procedure., (Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: The data on anti-arrhythmic effect of renin-angiotensin-aldesteron system blockers (RASB) in patients with atrial fibrillation (AF) are controversially discussed. The goal of this analysis was to identify cohort of patients with AF and hypertension, who may have benefit from RASB therapy after pulmonary vein isolation (PVI)., Methods: A total of 284 patients with AF and hypertension (paroxysmal AF [PAF]= 218, male = 185, age = 61 years, left ventricular ejection fraction = 60%, coronary artery disease = 42) considered for PVI were included. The patients with PAF were stratified according to time spent in AF (AF burden) within 3 months prior to admission ( 500 hours). Further patients were divided into two groups: (1) low-burden AF; (2) high-burden AF (PAF and persistent AF). In 195 patients, RASB therapy was administered. A 7-day continuous Holter electrocardiogram was performed after discharge, every 3 months thereafter and by symptoms., Results: Preventive effect of RASB was revealed in whole group (112 out of 195 [57%] vs 36 out of 89 [40%]; P = 0.025) and was more pronounced in patients with low-burden AF (79 out of 112 [71%] receiving RASB vs 27 out of 55 [49%] being on other drugs; P = 0.013). However, efficiency of RASB failed in patients with high-burden AF (33 out of 83 on RASB [40%] vs nine out of 34 on other drugs [27%]; P = 0.328)., Conclusions: Our data suggest that RASB appears to protect against AF recurrences after PVI in patients with low-burden paroxysmal AF. These results should be tested in a prospective study., (©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.)

Background: Delayed interatrial conduction, manifested on the electrocardiogram as a P wave >or=110 ms (interatrial block, IAB), is highly prevalent and associated with atrial fibrillation (AF). It is correlated with P-terminal force (Ptf; product of the duration and amplitude of the negative terminal phase of the P wave in lead V1). Our purpose was to describe the modifications of the P-wave duration and Ptf after pulmonary vein antrum isolation (PVAI) in patients with paroxysmal AF., Methods: PVAI was performed in 45 patients with paroxysmal AF, either with the cryoballoon technique (n = 15) or radiofrequency ablation (n = 30). Electrocardiograms were recorded before PVAI, 3 and 6 months after ablation., Results: From the sample (median age 60 [53; 66] years; female 40%), median P-wave duration was 122 [114; 134] ms before PVAI and 116 [106; 124] ms at 3-month follow-up (P < 0.001). IAB was observed in 42 patients (93.3%) before ablation and in 31 patients (68.9%) at 3-month follow-up. Median Ptf was 0.047 [0.020; 0.068] before ablation and 0.013 [0.004; 0.025] at 3-month follow-up (P < 0.001). Twenty-six patients (57.8%) had a Ptf > 0.04 mV x ms before ablation and only one (2.2%) at 3-month follow-up. P-wave duration and Ptf were not significantly modified between 3- and 6-month follow-up., Conclusion: The terminal part of the P wave is modified after PVAI, perhaps due to the loss of pulmonary vein antrum signals. P-wave duration and Ptf must be carefully interpreted after such a procedure. The prognostic value of these modifications should be evaluated.