Important factors in left atrial posterior wall isolation using 28‐mm cryoballoon ablation for persistent atrial fibrillation—Block line or isolation area?

Raise-up technique for the creation of left atrial roof lesion: A useful technique with cryoballoon for persistent atrial fibrillation

INTRODUCTION

Recent studies have reported the efficacy of the cryoballoon (CB)-guided left atrial roof block line (LARB) creation in patients with persistent atrial fibrillation (AF). However, it can be technically challenging to attach the balloon to the left atrial (LA) roof due to its anatomical variations. We designed a new procedure called the "Raise-up Technique," which may facilitate the firm adhesion of the CB to the LA roof during freezing. This study aimed to evaluate the efficacy of the Raise-up technique in LARB creation.

METHODS AND RESULTS

In total, 100 consecutive patients with persistent AF who underwent CB-LARB creation were enrolled. Fifty-seven patients underwent LARB creation using the Raise-up technique (Raise-up group), and the remaining 43 did not use it (control group). The Raise-up technique was performed as follows: An Achieve catheter was inserted as deeply as possible into the upper branch of the right superior pulmonary vein to anchor the CB. The balloon was placed below the targeted site on the LA roof and frozen. When the temperature of the CB reached approximately -10°C and the CB was easier to attach to the LA tissue, the CB was raised and pressed against the LA roof immediately by sheath advancement. Then the balloon could be in firm contact with the target site on the roof. If necessary, additional sheath advancement after sufficient freezing (-20°C to -30°C) was allowed the CB to have more firm and broad contact with the target site. LARB creation without touch-up ablation was achieved in 54 of 57 patients (94.7%) in the Raise-up group and 33 of 43 patients (76.7%) in the control group (p < .05). The lesion size of the LARB in the Raise-up group was significantly larger than that in the control group (15.2 cm2 vs. 12.8 cm2, p < .05). Moreover, the width of the LARB lesion in the Raise-up group was wider than that in the control group (32.0 mm vs. 26.6 mm, p < .05).

CONCLUSION

The Raise-up technique enabled the creation of seamless and thick LARB lesions with a single stroke. In addition, the CB-LARB lesions created using the Raise-up technique tended to be large, resulting in extensive debulking of the LA posterior wall arrhythmia substrates. In CB ablation for persistent AF, the Raise-up technique can be considered one of the key strategies for LARB creation.

How to perform effective cryoballooon ablation of the left atrial roof: Considerations after experiencing more than 1000 cases

INTRODUCTION

Cryoballoon ablation (CBA) of the left atrial (LA) roof in addition to a pulmonary vein isolation has been expected to improve the clinical outcomes post-atrial fibrillation (AF) ablation. We demonstrated the characteristics and efficacy of CBA of the LA roof through our experience with a large volume of procedures.

METHODS

Among 1036 AF ablation procedures with CBA of the LA roof, 834 patients who underwent a de novo ablation were analyzed.

RESULTS

Complete LA roof line conduction block was obtained in 767 patients (92.0%) solely by CBA (Group A). Compared with the other patients (Group B), the mean nadir balloon temperature during CBA of the LA roof (-44.5 ± 5.6°C for Group A vs. -40.5 ± 7.5°C for Group B, p < .01) and number of cryoballoon applications during the LA roof ablation with a circular mapping catheter located in the left superior pulmonary vein (1.3 ± 0.8 for Group A vs. 1.6 ± 1.0 for Group B, p = .02) were significantly lower in Group A. A multivariate analysis revealed that those were predictors of a complete LA roof conduction block after only CBA. The 1-year Kaplan-Meier atrial arrhythmia free rate estimates were 80.6% for Group A and 59.0% for Group B (p < .01).

CONCLUSION

Complete LA roof line conduction block could be obtained with a cryoballoon without touch-up ablation in most cases. The LA roof CBA with a circular mapping catheter located in the right superior pulmonary vein was preferable to obtaining complete LA roof conduction block, which was important with regard to the clinical outcomes.

Innovations in atrial fibrillation ablation

BACKGROUND

Catheter-based ablation to perform pulmonary vein isolation (PVI) has established itself as a mainstay in the rhythm control strategy of atrial fibrillation. This review article aims to provide an overview of recent advances in atrial fibrillation ablation technology.

METHODS

We reviewed the available literature and clinical trials of innovations in atrial fibrillation ablation technologies including ablation catheter designs, alternative energy sources, esophageal protection methods, electroanatomical mapping, and novel ablation targets.

RESULTS

Innovative radiofrequency (RF) catheter designs maximize energy delivery while avoiding overheating associated with conventional catheters. Single-shot balloon catheters in the form of cryoballoons, radiofrequency, and laser balloons have proven effective at producing pulmonary vein isolation and improving procedural efficiency and reproducibility. Pulsed field ablation (PFA) is a highly anticipated novel nonthermal energy source under development, which demonstrates selective ablation of the myocardium, producing durable lesions while also minimizing collateral damage. Innovative devices for esophageal protection including esophageal deviation and cooling devices have been developed to reduce esophageal complications. Improved electroanatomical mapping systems are being developed to help identify additional non-pulmonary triggers, which may benefit from ablation, especially with persistent atrial fibrillation. Lastly, the vein of Marshall alcohol ablation has been recently studied as an adjunct therapy for improving outcomes with catheter ablation for persistent atrial fibrillation.

CONCLUSIONS

Numerous advances have been made in the field of atrial fibrillation ablation in the past decade. While further long-term data is still needed for these novel technologies, they show potential to improve procedural efficacy and safety.

Does isolation of the left atrial posterior wall using cryoballoon ablation improve clinical outcomes in patients with persistent atrial fibrillation? A prospective randomized controlled trial

AIMS

Posterior wall isolation (PWI) of the left atrium (LA) adjunct to pulmonary vein isolation (PVI) by radiofrequency catheter ablation has shown favourable outcomes in patients with persistent atrial fibrillation (PeAF). This study was sought to investigate the efficacy and safety of additional PWI by cryoballoon ablation (CBA) alone in patients with PeAF.

METHODS AND RESULTS

Patients who underwent de novo CBA for PeAF (n = 100) were randomly assigned (1 : 1) to the PVI only group and PVI combined with PWI (PVI+PWI) group. Procedural and clinical outcomes were prospectively compared over a 12-month follow-up.

 

Baseline characteristics, including mean AF duration (56.2 ± 43.2 months) and LA size (48.2 ± 7.7 mm), were well-balanced between the groups. Successful PVI was achieved in all patients. In the PVI+PWI group, complete PWI by CBA was achieved in 31 (62%) patients. The LA indwelling and procedure times were significantly longer in the PVI+PWI group. The complication rates were not different between groups. During a mean follow-up of 457.9 ± 61.8 days, the recurrence rate of atrial tachyarrhythmia was significantly lower in the PVI+PWI group than in the PVI only group (24% vs. 46%; P = 0.035). The recurrence-free survival rate was significantly higher in the PVI+PWI group compared with the PVI only group, irrespective of complete PWI (log-rank P = 0.013). Multivariate analysis showed that adjunctive PWI [hazard ratio (HR) 0.255; P = 0.003] and LA size (HR 1.079; P = 0.014) were independent predictors of clinical recurrence.

CONCLUSION

Compared with PVI only, adjunctive PWI achieved exclusively by CBA resulted in better clinical outcomes without increasing complications in patients with PeAF.

The feasibility and safety of substrate modification on the left atrial roof area using a cryoballoon in atrial fibrillation ablation

BACKGROUND

Data on additional substrate modification using a cryoballoon beyond cryoballoon pulmonary vein isolation (CB-PVI) is limited. We sought to evaluate the efficacy and safety of substrate modification on the left atrial roof area using CBs (LAR-CBs) for atrial fibrillation (AF) patients.

METHODS

Eighty-one AF patients (70.0[62.5-77.0] years, 33 paroxysmal AF[PAF], 48 non-PAF) underwent LAR-CBs following CB-PVIs. Voltage maps were created with a high-resolution mapping system. Roof line conduction block was evaluated during the repeat procedure.

RESULTS

The total number of applications for the CB-PVI and LAR-CB were 5.0 ± 1.2 and 3.8 ± 0.7, and both were significantly greater in non-PAF than PAF patients. LA roof areas had continuous scar in 61/79(77.2%) patients, and the mean balloon temperature was significantly lower in patients with continuous scar than those without (-39.3 ± 3.8 vs. 36.0 ± 4.6 °C, p = 0.004). The single procedure 1-year AF freedom was 87.6% (7.5% on antiarrhythmic drug) and was similar between PAF and non-PAF patients (p = 0.14). Twelve (14.8%) patients underwent a second procedure 5.5(2.2-7.5) months later, and a mean of 1.3 ± 0.5 PVs were reconnected in 7/12(58.3%) patients. Electrical conduction block across the roof line was proven in 3/12(25.0%) patients. There were 6(7.4%) complications related to the procedures, including iatrogenic roof dependent atrial tachycardia, takotsubo cardiomyopathy, and severe pericarditis in 1, 1, and 2 patients, respectively.

CONCLUSIONS

LA roof area substrate modification using CBs yielded a high arrhythmia freedom after single procedures. However, a low incidence of electrical conduction block across the line during the chronic phase and delayed complications were the major concerns.

Cryoballoon ablation of the left atrial posterior wall reduces recurrence of persistent atrial fibrillation in patients with non-paroxysmal atrial fibrillation

BACKGROUND

This study aimed to clarify the clinical outcomes of cryoballoon ablation of the left atrial (LA) posterior wall (LAPW), including the LA roof, in patients with non-paroxysmal atrial fibrillation (AF).

METHODS

We analyzed the outcomes of 284 patients with non-paroxysmal AF, of whom 210 underwent the cryoballoon ablation of the LAPW, including the LA roof, in addition to pulmonary vein isolation with a cryoballoon.

RESULTS

Complete conduction block at the LA roof was obtained in 95.7% (201/210) of patients, and LAPW was isolated in 83.3% (130/156) of patients. Over 372 (range, 208-477) days of follow-up, atrial arrhythmia recurrence was observed in 84 (29.6%) patients, and atrial tachycardia (AT) recurrence accounted for 27.4% of cases. The prevalence of LA roof cryoballoon ablation was significantly higher in patients without recurrence than in those with recurrence (78.6% vs. 63.1%, respectively; p = .01), especially those with persistent AF recurrence (77.0% vs. 55.0%, p = .01). No significant difference was found in the prevalence of AT recurrence between patients who had undergone additional LAPW ablation and those who had not. Durable LA roof lesions were confirmed in 29 (72.5%) of 40 patients who underwent redo ablation.

CONCLUSIONS

Cryoballoon ablation of the LAPW leads to a sufficient acute success rate of complete conduction block and durable lesions of the LA roof without increasing AT recurrence risk. The prevalence of persistent AF recurrence decreases after additional cryoballoon ablation of the LAPW in patients with non-paroxysmal AF.

Catheter ablation for atrial fibrillation in elderly patients: Systematic review and a meta-analysis

AIMS

Catheter ablation (CA) is established therapy for patients with atrial fibrillation (AF); however, there is a limited understanding of CA in elderly patients. We studied the long-term efficacy and periprocedural safety of radiofrequency and cryoballoon CA for elderly patients with AF.

METHODS

PubMed and Embase were searched through April 2021 to investigate the comparative outcomes between elderly and non-elderly patients who underwent CA for AF. The primary efficacy and safety endpoints were AF recurrence and procedure-related complications, respectively. Subgroup analyses were performed by procedure type of CA.

RESULTS

The search identified 20 observational studies with 110,606 patients, including 8009 elderly patients (7.2%). The risk of AF recurrence was not significantly different between elderly and non-elderly patients (hazard ratio, 1.37; 95% confidence interval [CI], 0.94-2.00; p = .10, I²  = 70%). However, relative to the non-elderly, elderly patients had significantly higher major complications (risk ratio [RR], 1.32; 95% CI, 1.14-1.54], p < .01, I²  = 0%) and overall complications (RR, 1.26; 95% CI, 1.00-1.57; p = .05, I²  = 56%) with higher cerebrovascular events (RR, 1.68; 95% CI, 1.25-2.25; p = < .01, I²  = 0%). Subgroup analysis with cryoballoon CA showed that procedure-related complications in elderly patients were similar to those in non-elderly patients but not with radiofrequency CA.

CONCLUSIONS

CA for AF in elderly patients has comparable long-term efficacy compared to that in non-elderly patients; however, the incidence of procedure-related complications were higher in elderly patients. Cryoballoon CA did not confer a higher procedure-related risk in elderly patients.

Prevalence of gastric hypomotility after additional cryoballoon ablation of the left atrial roof

INTRODUCTION

Gastric hypomotility (GH) is a major complication of atrial fibrillation (AF) ablation. We aimed to clarify whether additional cryoballoon ablation (CBA) of the left atrial (LA) roof is associated with GH.

METHODS AND RESULTS

This study included 54 patients with non-paroxysmal AF who underwent CBA for pulmonary vein isolation and of the LA roof line. GH was defined according to the results of esophagogastroscopy performed 2 days after ablation. GH was observed in 10 patients. There were significant differences in LA diameter (LAD), right inferior pulmonary vein (RIPV) diameter, and the height of the LA roof from the point where the LA posterior wall and esophagus make contact between patients with (GH+) and without GH (GH-) (LAD: 41.0 [36.3-41.8] mm vs. 46.5 [42.8-50.0] mm, p < .01; RIPV diameter: 19.7 [19.0-20.5] mm vs. 23.2 [21.2-24.9] mm, p < .01; height of LA roof: 5.7 [5.1-6.1] mm vs. 8.8 [7.1-11.2] mm for, p < .01, respectively). Multivariate analysis revealed that LA roof height was a predictor of GH. Moreover, Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index (PAGI-SYM) scores increased significantly 1 week after ablation (from 1.0 [0.0-2.8] to 5.0 [3.0-11.0], p = .03) in patients with GH.

CONCLUSION

The height of the LA roof may be a predictor of GH after CBA of the LA roof line. Additionally, GH-related symptoms may still appear 1 week after ablation.

Comparison of Cryoballoon and Contact Force-Sensing Radiofrequency Ablation for Persistent Atrial Fibrillation in Clinical Practice

BACKGROUND

Outcomes of cryoballoon ablation for persistent atrial fibrillation (AF) are unclear, especially in Japanese patients, so the effectiveness and safety of cryoballoon ablation in clinical practice were retrospectively compared with those of contact force-sensing radiofrequency (CFRF) ablation including the high-power protocol.Methods and Results:Consecutive patients with persistent AF were reviewed, and 253 and 265 patients who underwent cryoballoon and CFRF ablation, respectively, were enrolled. The primary endpoint was atrial arrhythmia recurrence. The secondary endpoints were periprocedural complications and repeat ablation. The rate of additional left atrial (LA) ablation after pulmonary vein isolation (PVI) was similar between groups (68.8% cryoballoon vs. 74.0% CFRF, P=0.19). Freedom from atrial arrhythmia recurrence was comparable between groups over a follow-up of 25.5±12.5 months (72.3% cryoballoon vs. 69.8% CFRF; adjusted hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.59-1.21, P=0.36). Outcomes were similar in the subgroups of PVI alone and PVI plus additional LA ablation. LA posterior wall isolation, absence of defragmentation, and low creatine clearance, but not catheter selection, were associated with the primary endpoint. Periprocedural complications (adjusted HR 0.73, 95% CI 0.34-1.54, P=0.41) and repeat ablation (adjusted HR 1.11, 95% CI 0.71-1.74, P=0.64) were similar for both procedures.

CONCLUSIONS

Cryoballoon ablation for persistent AF in Japanese clinical practice had acceptable outcomes comparable to those of advanced CFRF ablation.

Cryoballoon left atrial roof ablation for persistent atrial fibrillation ∼Analysis with high-resolution mapping system∼

BACKGROUND

Additional benefit of cryoballoon left atrial roof line ablation (CB-RA) beyond cryoballoon pulmonary vein isolation (CB-PVI) is suggested in patients with persistent atrial fibrillation (PsAF). We sought to investigate the feasibility of CB-RA for PsAF and to determine the ablation area.

METHODS AND RESULTS

Fifty-three PsAF patients (67[58.5-75.5] years, 36 men, 11 longstanding PsAF) underwent CB-PVI. Subsequently, 44(83.0%) out of 53 patients underwent additional CB-RA. Voltage maps were created in all patients with a high-resolution mapping system. The total number and duration of CB-RAs were 3.9±0.7 and 468±84 seconds. LA roof areas were complete low voltage areas (LVAs) /scar in 37/44(84.1%) patients ("complete roof modification"). The normal LA posterior wall (LAPW) voltage area was 6.1(4.1-8.4)cm2, and the %LAPW isolation area was 61.0(47.2-71.7)%. The %LAPW isolation area was significantly greater in CB-RA patients than those without (64.0[54.2-73.2] vs. 45.0[39.5-50.5]%, p = 0.041) despite significantly larger LAs in the former group. The %LAPW isolation area was significantly greater in patients with transverse LA diameters <45 mm than those ≥45 mm (p<0.0001). The single procedure 1-year AF freedom was 87.4% (22.5% on antiarrhythmic drug) and tended to be higher in CB-RA patients than those without. Among the 44 CB-RA patients, it was significantly higher in patients with a complete roof modification than those without (94.4% vs. 75.0%, p = 0.0049). One CB-RA patient experienced a delayed cardiac tamponade requiring drainage at 4-months post-procedure.

CONCLUSIONS

CB-RA significantly expanded the LAPW isolation area, and a complete roof modification resulted in a high arrhythmia freedom in PsAF patients. This article is protected by copyright. All rights reserved.

Effectiveness of Radiofrequency Catheter Ablation Using Ablation Index Versus Second Generation Cryoballoon in the Treatment of Persistent Atrial Fibrillation: A Matching-Adjusted Indirect Comparison

Introduction

Both radiofrequency (RF) and cryoballoon (CB) ablation are treatment options for persistent atrial fibrillation (PsAF). An important recent innovation in RF ablation is Ablation Index (AI), known also as the VISITAG SURPOINT™ Module, a composite lesion quality marker whose use has been shown to significantly reduce the incidence of acute and late pulmonary vein (PV) reconnection and the recurrence of atrial arrhythmias in PsAF. Due to a lack of direct comparative evidence between the latest generations of technologies, there is uncertainty regarding the best treatment option in PsAF. The objective of the present study was to conduct a matching-adjusted indirect treatment comparison (MAIC) using individual patient-level data (IPD) to assess the comparative effectiveness of the THERMOCOOL SMARTTOUCH™ Catheter or the THERMOCOOL SMARTTOUCH™ SF Catheter with AI/VISITAG SURPOINT™ Module (STAI) versus the second-generation CB catheter (Arctic Front Advance™; herein referred to as CB) with respect to 12-month atrial arrhythmia recurrence, fluoroscopy time, and procedural efficiency.

Methods

IPD for STAI were obtained from four investigator-initiated studies and were pooled. Comparable CB studies identified from a systematic literature review were also pooled. In the absence of a common treatment arm between STAI and CB studies, an unanchored MAIC was conducted. The primary analysis compared the pooled STAI IPD to the pooled CB cohort, with corrections for differences across trials, including eligibility criteria and patient baseline characteristics. Scenario and sensitivity analyses were conducted to assess the robustness of the primary analysis.

Results

In the primary analysis, which was adjusted for left atrial diameter (LAD), age, diabetes, and sex, STAI was associated with a statistically significant 65% relative reduction in the rate of arrhythmia recurrence compared to CB at 12-month follow-up (HR 0.35; 95% CI 0.23, 0.52). STAI was associated with shorter total fluoroscopy time than CB but longer procedure time. Results were consistent across scenario and sensitivity analyses.

Conclusion

Radiofrequency ablation with AI significantly reduced atrial arrhythmia recurrence at 12-month follow-up and fluoroscopy time compared to CB, with longer procedure times.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01846-z.

How does the level of pulmonary venous isolation compare between pulsed field ablation and thermal energy ablation (radiofrequency, cryo, or laser)?

Aims

We studied the extent/area of electrical pulmonary vein isolation (PVI) after either pulsed field ablation (PFA) using a pentaspline catheter or thermal ablation technologies.

Methods and results

In a clinical trial (NCT03714178), paroxysmal atrial fibrillation (PAF) patients underwent PVI with a multi-electrode pentaspline PFA catheter using a biphasic waveform, and after 75 days, detailed voltage maps were created during protocol-specified remapping studies. Comparative voltage mapping data were retrospectively collected from consecutive PAF patients who (i) underwent PVI using thermal energy, (ii) underwent reablation for recurrence, and (iii) had durably isolated PVs. The left and right PV antral isolation areas and non-ablated posterior wall were quantified. There were 20 patients with durable PVI in the PFA cohort, and 39 in the thermal ablation cohort [29 radiofrequency ablation (RFA), 6 cryoballoon, and 4 visually guided laser balloon]. Pulsed field ablation patients were younger with shorter follow-up. Left atrial diameter and ventricular systolic function were preserved in both cohorts. There was no significant difference between the PFA and thermal ablation cohorts in either the left- and right-sided PV isolation areas, or the non-ablated posterior wall area. The right superior PV isolation area was smaller with PFA than RFA, but this disappeared after propensity score matching. Notch-like normal voltage areas were seen at the posterior aspect of the carina in the balloon sub-cohort, but not the PFA or RFA cohorts.

Conclusion

Catheter-based PVI with the pentaspline PFA catheter creates chronic PV antral isolation areas as encompassing as thermal energy ablation.

Segmental nonocclusive cryoballoon ablation of pulmonary veins and extrapulmonary vein structures: Best practices III

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.

Cryoballoon ablation for extrapulmonary vein targets

PURPOSE OF REVIEW

Cryoballoon catheter can create large and contiguous lesions with stable contact during ablation. It has proven to be well tolerated and effective in pulmonary vein isolation. But atrial arrhythmias, including atrial fibrillation, atrial tachycardia, and atrial flutter (AFL), also relate to many extrapulmonary vein targets. It is necessary to understand the current evidence for the use of cryoballoon ablation for targets outside of pulmonary veins.

RECENT FINDINGS

Studies have shown that the cryoballoon ablation can be used in extrapulmonary vein area, including left atrium roof, left atrial appendages, posterior left atrial wall, mitral isthmus, and right atrial appendage. The results indicate cryoballoon ablation is an effective and well-tolerated treatment option for the atrial arrhythmias in these locations outside of pulmonary vein when clinical necessary.

SUMMARY

The cryoballoon ablation can safely and effectively perform contiguous linear lesions, structure isolations, and local ablation for targets outside of the pulmonary veins.

Does pulsed field ablation regress over time? A quantitative temporal analysis of pulmonary vein isolation

BACKGROUND

The tissue specificity of pulsed field ablation (PFA) makes it an attractive energy source for pulmonary vein (PV) isolation (PVI). However, beyond each PFA lesion's zone of irreversible electroporation and cell death, there may be a surrounding zone of reversible electroporation and cell injury that could potentially normalize with time.

OBJECTIVE

The purpose of this study was to assess whether the level of electrical PVI that is observed acutely after PFA regresses over time.

METHODS

In a clinical trial, patients with paroxysmal atrial fibrillation underwent PVI using a biphasic PFA waveform delivered through a dedicated, variably deployable multielectrode basket/flower catheter. Detailed voltage maps were created using a multispline diagnostic catheter immediately after PFA and again ∼3 months later in a prospective, protocol-specified reassessment procedure. We analyzed 20 patients who underwent PFA with durable PVI and available maps from both time points. To compare the ablated zones, the left- and right-sided PV antral isolation areas and nonablated posterior wall area were quantified and the distances between left and right PV low-voltage edges were measured.

RESULTS

A comparison of voltage maps immediately after PFA and at a median of 84 days (interquartile range 69-90 days) later revealed that there was no significant difference in either the left- and right-sided PV antral isolation areas or nonablated posterior wall area. The distances between low-voltage edges on the posterior wall were also not significantly different between the 2 time points.

CONCLUSION

This study demonstrates that the level of PV antral isolation after PFA with a multielectrode PFA catheter persists without regression.

Single procedural outcomes in the setting of percutaneous ablation for persistent atrial fibrillation: a propensity-matched score comparison between different strategies

BACKGROUND

Catheter ablation for persistent atrial fibrillation (persAF) is associated with less favorable outcomes than for paroxysmal AF. To improve success rates, left atrial (LA) substrate modification is frequently performed in addition to pulmonary vein isolation (PVI). The purpose of the study was to compare 4 different ablation approaches using radiofrequency catheter ablation (RFCA) or cryoballoon ablation (CB-A) for persAF and to evaluate the respective outcomes on a midterm follow-up of 12 months.

METHODS

We did a propensity score-matched comparison of 30 patients undergoing PVI + LA posterior wall isolation (LAPWI) with CB-A, 30 patients who underwent PVI + linear ablation (roof and mitral lines) using RFCA, 60 patients with PVI alone using CB-A, and 60 patients who had PVI alone using RFCA. The endpoint was recurrence of documented atrial tachyarrhythmias (ATas) > 30 s at 1-year follow-up.

RESULTS

After 12 months, freedom from ATas after a single procedure was 83.3% in the PVI + LAPWI group, 46.7% in the PVI + linear ablation group, 58.3% in the PVI-alone CB-A group, and 61.6% PVI-alone RFCA (p = 0.03). Moreover, freedom from ATas was significantly higher comparing the PVI + LAPWI group with each of the other groups.

CONCLUSIONS

In this propensity-matched comparison of strategies for persAF, LAPW ablation in addition to PVI with CB-A seems to improve 1-year outcome in comparison to PVI + linear ablation using RFCA and to PVI alone using RFCA or CB-A. Randomized comparisons are eagerly awaited.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cryoballoon ablation dosing: From the bench to the bedside and back

To date, multiple modes of research have been leveraged to study the optimal cryoballoon ablation parameters to safely, effectively, and efficiently isolate the pulmonary veins for the treatment of atrial fibrillation. Basic scientific investigation, preclinical studies, clinical observations, trials, and, more recently, computational modeling have helped to generate and test new hypotheses for the advancement of cryoballoon treatment in patients with atrial fibrillation. In this review, we examine the data and evidence that have contributed to the development of patient-tailored dosing strategies that are currently used for pulmonary vein isolation by using the Arctic Front series of cryoballoon ablation catheters.