Quantitative comparison of the isolation lesions between conventional- and larger-sized visually guided laser balloon ablation

BACKGROUND

The importance of a wider circumferential isolation of the pulmonary veins (PV), which includes a large portion of the left atrial posterior wall (LAPW), has been suggested in several studies. However, the extended isolation area using a larger inflated visually guided laser balloon (VGLB) ablation remains to be elucidated.

METHODS

Seventy-eight patients with atrial fibrillation (AF) who underwent VGLB ablation were enrolled in this prospective study. An electroanatomic map of the left atrium was obtained before and after PV isolation (PVI) using a conventional-sized VGLB. The isolation areas were extended by the largest-sized VGLB ablation and remapped in the same manner. After the ablation, isolation areas were calculated with CARTO-3 system. The one-year atrial arrhythmia (Ata) recurrence was assessed.  RESULTS: The largest-sized VGLB ablation yielded statistically greater areas of isolation in left-sided PV antrum (PVA) (11.5 ± 2.3 cm2 vs. 15.9 ± 3.5 cm2, P < .001) and right-sided PVA (14.2 ± 3.3 cm2 vs. 20.6 ± 4.4 cm2, P < .001) than the conventional-sized VGLB. Further, non-ablated LAPW (12.3 ± 4.4 cm2 vs. 7.8 ± 3.9 cm2, P < .001) was significantly reduced after largest-sized VGLB ablation, compared to the conventional-sized VGLB ablation. The one-year Ata freedom was 83.7% in patients with paroxysmal AF and 96.4% in those with persistent AF.

CONCLUSION

The largest-sized VGLB ablation technique can create a significantly wider isolation area of PVA and debulk a large amount of LAPW than the conventional-sized VGLB ablation. The one-year outcome was similarly high in paroxysmal and persistent AF.

Cryoballoon ablation of non-PV triggers in persistent atrial fibrillation

Cryoballoon-based catheter ablation has emerged as an efficacious and safe therapeutic intervention for patients with paroxysmal atrial fibrillation (PAF). PAF is primarily associated with the triggers in the pulmonary vein (PV). However, persistent atrial fibrillation (PeAF) is a complex condition that involves changes in the atrial substrate and the presence of non-PV triggers. Therefore, a comprehensive treatment approach is necessary for patients with PeAF. Utilizing a 3D electroanatomical map, the radiofrequency-based ablation technique adeptly identifies and targets the atrial substrate and non-PV triggers. On the other hand, the cryoballoon-based AF ablation was initially designed for PV isolation. However, its single-shot feature makes it a great choice for electrophysiologists looking to address non-PV triggers. It is possible to target the left atrial appendage (LAA), superior vena cava (SVC), left atrial roof, and posterior wall using the apparatus's unique configuration and ablation abilities. This review focuses on the increasing literature regarding cryoballoon-based methods for non-PV trigger ablation. Specifically, it delves into the technical procedures used to isolate the LAA, SVC, and ablate the left atrial roof and posterior wall.

Cryoballoon vs. laser balloon ablation for atrial fibrillation: a meta-analysis

Background

Cryoballoon ablation (CBA) and laser balloon ablation (LBA) are two innovative ways for the treatment of atrial fibrillation (AF). This study aimed to evaluate the efficacy and safety of cryoballoon ablation and laser balloon ablation in patients with AF.

Methods

We searched Pubmed, Embase, Ovid, Web of Science and other databases for comparative trials comparing CB and LB ablation in the treatment of AF, from establishment of database to August, 2023.

Results

A total of 13 studies and 3,582 patients were included (CBA, n = 2,308; LBA, n = 1,274). There was no difference between CBA and LBA in acute PVI rate per vein, 12-months recurrence rate of AF, 12-months recurrence rate of atrial arrhythmia, occurrence rate of pericardial tamponade, occurrence rate of inguinal complications. LBA presented a lower acute PVI rate per patients (CBA 97.0% vs. LBA 93.4%, RR = 1.04, 95%CI: 1.01-1.07). Transient nerve palsy was more likely to occur after CBA (CBA 2.7% vs. LBA 0.7%, RR = 4.25, 95%CI: 2.06-8.76). However, the occurrence of persistent nerve palsy between CBA and LBA groups were similar (CB 1.4% vs. LB 1.0%, RR = 1.09, 95%CI: 0.55-2.14). In terms of procedural duration, the procedural time of CBA was shorter than that of LBA (WMD = -26.58, 95%CI: -36.71-16.46).

Conclusions

Compared with LBA, CBA had a shorter procedural duration. There was a higher incidence of transient but not persistent phrenic nerve palsy after CBA.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=272607 Identifier (CRD42021272607).

Efficacy and safety of visually guided laser balloon versus cryoballoon ablation for paroxysmal atrial fibrillation: a systematic review and meta-analysis

Background

Newly developed catheter ablation (CA) techniques, such as laser balloon ablation (LBA) and cryoballoon ablation (CBA), have been introduced in recent years and emerged as valuable alternatives to conventional radiofrequency CA strategies for paroxysmal atrial fibrillation (PAF) patients. However, evidence comparing LBA and CBA remain controversial. Thus, we conducted this meta-analysis to assess the efficacy and safety between these two techniques.

Methods

Scientific databases (PubMed, Embase) and relevant websites (the Cochrane Library, ClinicalTrials.gov) were systematically searched from inception to March 2023. The primary outcomes of interest were the AF recurrence and the procedure-related complications. Secondary outcomes included procedural time, fluoroscopy time, and left atrial (LA) dwell time.

Results

Seven clinical trials with a total of 637 patients were finally enrolled. No significant differences were found between LBA and CBA in terms of AF recurrence [16.3% vs. 22.7%, odds ratio (OR) = 0.66, 95% confidence interval (CI): 0.42-1.05, p = 0.078] or total procedural-related complications (8.4% vs. 6.4%, OR = 1.33, 95% CI: 0.71-2.51, p = 0.371). LBA had a significantly longer procedural time [weighted mean difference (WMD) = 38.03 min, 95% CI: 13.48-62.58 min, p = 0.002] and LA dwell time (WMD = 46.67 min, 95% CI: 14.63-78.72 min, p = 0.004) than CBA, but tended to have shorter fluoroscopy time.

Conclusions

LBA and CBA treatment have comparable efficacy and safety for PAF patients. LBA was associated with longer procedural and LA dwell times compared with CBA. Further large-scale studies are warranted to compare these two techniques with the newest generations.Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=426513, identifier (CRD42023426513).

Bayesian network meta-analysis comparing hot balloon, laser balloon and cryoballoon ablation as initial therapies for atrial fibrillation

BACKGROUND

Balloon-based catheter ablation (CA) technologies, including hot balloon ablation (HBA), laser balloon ablation (LBA) and cryoballoon ablation (CBA) have been introduced in recent years as alternatives to conventional radiofrequency ablation therapy for atrial fibrillation (AF). However, the results remain controversial concerning the optimal approach. Thus, we conducted a network meta-analysis (NMA) to comprehensively evaluate the efficacy and safety of HBA, LBA and CBA.

METHODS

Clinical trials comparing the efficacy and safety of HBA, LBA and CBA were identified through a systematic search up to October 2022. The primary outcomes of interest were the recurrence of AF and procedure-related complications.

RESULTS

Twenty clinical trials with a total of 1,995 patients were included in the meta-analysis. The NMA results demonstrated that HBA, LBA and CBA had comparable AF recurrence rates (HBA vs. CBA: odds ratio OR = 0.88, 95% credible interval CrI: 0.56-1.4; LBA vs. CBA: OR = 1.1, 95% CrI: 0.75-1.5; LBA vs. HBA: OR = 1.2, 95% CrI: 0.70-2.0) and procedure-related complications (HBA vs. CBA: OR = 0.93, 95% CrI: 0.46-2.3; LBA vs. CBA: OR = 1.1, 95% CrI: 0.63-2.1; LBA vs. HBA: OR = 1.2, 95% CrI: 0.44-2.8). The surface under the cumulative ranking curve (SUCRA) suggested that HBA may be the optimal approach concerning the primary outcomes (SUCRA = 74.4%; 61.1%, respectively). However, HBA (40.1%) had a significantly higher incidence of touch-up ablation (TUA) than LBA (8.5%, OR = 2.8, 95% CrI: 1.1-7.1) and CBA (11.9%, OR = 3.7, 95% CrI: 1.9-7.5). LBA required more procedure time than CBA [mean difference (MD = 32.0 min, 95% CrI: 19.0-45.0 min)] and HBA (MD = 26.0 min, 95% CrI: 5.6-45.0 min), but less fluoroscopy time than HBA (MD = -9.4 min, 95% CrI: -17.0--2.4 min).

CONCLUSIONS

HBA, LBA and CBA had comparable efficacy and safety as initial treatments for AF. HBA ranked highest in the primary outcomes, but at the cost of a higher incidence of TUA and longer fluoroscopy time.

SYSTEMATIC REVIEW REGISTRATION

www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022381954, identifier: CRD42022381954.

Comparison of maximum-sized visually guided laser balloon and cryoballoon ablation

Balloon ablation therapy has recently been used for atrial fibrillation (AF) ablation. Laser balloons possess the property in which the balloon size can be changed. Standard laser balloon ablation (Standard LBA) was followed by additional ablation using a maximally extended balloon (Extended LBA) and its lesion characteristics were compared to cryoballoon ablation (CBA), another balloon technology. From June 2020 to July 2021, patients with paroxysmal AF who underwent an initial pulmonary vein (PV) isolation were enrolled. Sixty-five patients with paroxysmal AF were included, 32 in the LBA and 33 in the CBA group. To measure the isolated surface area after the ablation procedures, left atrial voltage mapping was performed after Standard LBA, Extended LBA, and CBA. The baseline patient characteristics did not differ between LBA and CBA. Extended LBA could successfully increase the isolated area more than Standard LBA for all four PVs. Compared to CBA, the isolated area of both superior PVs was significantly greater with Extended LBA (left superior PV: 8.5 ± 2.1 vs 7.3 ± 2.4, p = 0.04, right superior PV: 11.4 ± 3.7 vs 8.7 ± 2.7, p < 0.01), and thus the non-isolated posterior wall (PW) was smaller (8.5 ± 3.4 vs 12.4 ± 3.3, p < 0.01). Nevertheless, changes in the cardiac injury markers were significantly lower with LBA than CBA. There was no significant correlation between the cardiac injury level and isolated area in both groups. In conclusion, Extended LBA exhibited a significantly greater isolation of both superior PVs and resulted in a smaller non-isolated PW, but the cardiac injury markers were significantly suppressed as compared to CBA.

Pulsed field ablation for pulmonary vein isolation: real-world experience and characterization of the antral lesion size compared with cryoballoon ablation

BACKGROUND

Pulsed field ablation (PFA) is a new, non-thermal technology in the treatment of atrial fibrillation (AF). Early investigations have shown a promising safety profile with durable pulmonary vein isolation (PVI) and large antral lesions. However, clinical data remains scarce.

METHODS

We investigated a cohort of 43 patients. Twenty-three patients underwent PVI with PFA in our hospital and we analyzed them with regard to procedural characteristics and with regard to the size of acute antral lesion which was estimated by using an electroanatomical map of the left atrium (LA). We compared these data with data of 20 patients who had undergone cryoballon (CB) PVI in our hospital.

RESULTS

We could show acute isolation of all veins in all patients (100% PFA, 100% CB). Post-ablation high-density mapping revealed no early reconnection (0%). The acute antral lesion size of PFA was significantly higher compared to the CB (67.03 ± 12.69% vs. 57.39 ± 10.91%, p = 0.01). In the PFA group, we found no acute phrenic nerve injury, no major or minor bleeding, and no tamponade but one (4.34%) patient suffered from a stroke. Transient hypotension was observed frequently as well as transient bradycardia or asystole episodes requiring right ventricular pacing. In the CB group, no complications occurred. Furthermore, we discuss practical issues on PFA procedures.

CONCLUSIONS

PFA is a promising technology with high acute PV isolation rate and large antral lesions compared to CB. However, larger trials with more patients and data on long-term freedom of AF but also complications are needed.

Laser balloon in pulmonary vein isolation for atrial fibrillation: current status and future prospects

INTRODUCTION

Visually guided laser balloon (LB) catheter has been an established modality dedicated for pulmonary vein (PV) isolation in patients with atrial fibrillation. The newly updated version of this novel device has technically evolved recent years.

AREAS COVERED

This review will summarize the contemporary technical evolution of LB catheter. Available efficacy outcomes and the historical change of ablation style will be evaluated. Furthermore, the future perspectives for clinical practice are discussed.

EXPERT COMMENTARY

The initial LB ablation system provided comparable clinical results in PV isolation with other technologies, but with a unique strategical concept enabling the direct visualization of the tissue to cauterize. With multigenerational development, the LB catheter has been equipped with more compliant balloon for favorable PV occlusion and a robotically motor driven continuous ablation mode (RAPID mode). These technical innovations changed the concept of the ablation strategy using LB catheter as 'point-by-point' into 'single-shot' fashion. The remaining tasks are further improvements such as equipping with real-time recording system of intracardiac electrogram, durable structured balloon and the instrument for visualizing the cauterization area in a 360-degree panoramic view, which includes potential possibilities to develop this novel device to the more optimal device for PV isolation.

Rationale and Outcomes of Cryoballoon Ablation of the Left Atrial Posterior Wall in Conjunction with Pulmonary Vein Isolation

There is strong evidence in support of pulmonary vein isolation (PVI) with concomitant left atrial (LA) posterior wall (PW) isolation (PWI) for the treatment of patients with persistent atrial fibrillation (persAF). While this may be achieved using surgical and catheter-based strategies, there is growing interest in performing this approach using the cryoballoon. There are several potential advantages to this strategy. First, lesions created using the current-generation cryoballoons are typically large and durable. Second, cryoballoon ablation offers a simple technique to directly ablate and debulk the LAPW. Moreover, some consider cryoenergy a safer modality specifically with regard to collateral structures (ie, the esophagus). Based on the available data, cryoballoon PVI + PWI is associated with greater intraprocedural AF terminations and reductions in long-term AF recurrence (typically by ~20%), as compared to PVI alone in patients with persAF, but with similar rates of adverse events. As such, PVI + PWI has emerged as a significant predictor of freedom from recurrent AF (odds ratio: 3.67, 95% confidence interval: 1.44-9.34; p = 0.006) as well as all atrial arrhythmias (hazard ratio: 2.04, 95% confidence interval: 1.15-3.61; p = 0.015). Adjunct radiofrequency ablation to complete PWI is required in at least one-third of the patients, and this need is highly predicted by the LA size (significantly increased with an LA diameter > 48 mm). LAPW reconnection also seems to be associated with LA dimension, particularly an LA diameter greater than 48 mm (negative predictive value: 89.7%). Nevertheless, based on the analysis of patients who underwent repeat electrophysiology study for arrhythmia recurrences, cryoballoon PVI + PWI yields acceptable long-term durability (> 80%).

Validation of lesion durability following pulmonary vein isolation using the new third-generation laser balloon catheter in patients with recurrent atrial fibrillation

BACKGROUND

The second- and third-generation endoscopic ablation systems (EAS2 and EAS3) have been launched in recent years. We aimed to assess the lesion durability as well as gap localization using the multigenerational novel technologies in patients with recurrent atrial fibrillation (AF).

METHODS

Consecutive patients who underwent second ablation for recurrent AF following the initial pulmonary vein isolation (PVI) with EAS2 or EAS3 were retrospectively investigated. The persistent durability of PVI, gap localization at the second procedure, and procedural/anatomical features of durable PVI were analyzed.

RESULTS

Among 225 patients treated with EAS3 (N = 125) and EAS2 (N = 100), 34 patients (EAS3: 13 patients, 50 PVs, EAS2: 21 patients, 82 PVs) underwent a second procedure because of recurrent AF mean 11.9 ± 9.3 months after the initial procedure. Persistent isolation of all four PVs was recorded in 6 (46.2%) patients in EAS3 group and 4 (19.1%) patients in EAS2 group (p = 0.130). Ninety-one out of 132 (68.9%) PVs were persistently isolated with a higher rate in EAS3 group (82.0% vs. EAS2 group: 61.0%, p = 0.0113). A total of 45 gaps were recorded in 41 PVs. Right superior PV (RSPV) was the predominantly common reconnected vein (15 gaps, 14 PVs) irrespective of generations (EAS3: 4 gaps in 3 PVs and EAS2: 12 gaps in 11 PVs). Logistic multivariate regression analysis revealed ablation without reduced energy dose (5.5-7 W) as an independent predictor of durable PVI [adjusted OR: 3.70, 95% CI (1.408-10.003)], p = 0.008].

CONCLUSION

The technical innovation resulted in a higher lesion durability in EAS3-guided PVI in patients with recurrent AF. The most common gap location was found at RSPV in successor EASs. Ablation without reduced energy was a predictor of durable PVI in successor EASs.

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.

Concomitant Pulmonary Vein and Posterior Wall Isolation Using Cryoballoon With Adjunct Radiofrequency in Persistent Atrial Fibrillation

OBJECTIVES

The aim of this multicenter, randomized, single-blind study was to prospectively evaluate the short-and long-term outcomes of pulmonary vein isolation (PVI) versus PVI with concomitant left atrial posterior wall isolation (PWI) using the cryoballoon in patients with symptomatic persistent/long-standing persistent atrial fibrillation (P/LSP-AF).

BACKGROUND

Some studies have suggested a clinical benefit associated with PVI+PWI in patients with P/LSP-AF. However, there are limited safety and efficacy data on this approach using cryoballoon ablation.

METHODS

The immediate and long-term outcomes in patients with P/LSP-AF randomized to PVI (n = 55) versus PVI+PWI (n = 55) using the cryoballoon were prospectively examined.

RESULTS

Baseline characteristics were similar. PVI was achieved in all patients (21 ± 11 min). PWI was attained using 23 ± 8 min of cryoablation. Adjunct radiofrequency ablation was required in 4 of 110 patients (7.3%) to complete PVI (3 ± 2 min) and in 25 of 55 patients (45.5%) to complete PWI (4 ± 6 min). Although left atrial dwell time (113 ± 31 min vs. 75 ± 32 min; p < 0.001) and total procedure time (168 ± 34 min vs. 127 ± 40 min; p < 0.001) were longer with PVI+PWI, this cohort required fewer intraprocedural cardioversions (89.1% vs. 96.4%; p = 0.04). Adverse events occurred in 5.5% in each group (p = 1.00). However, the incidence of recurrent atrial fibrillation at 12 months was significantly lower with PVI+PWI (25.5% vs. 45.5%; p = 0.028). Additionally, in a multivariate analysis, PVI+PWI emerged as a significant predictor of freedom from recurrent atrial fibrillation (odds ratio: 3.67; 95% confidence interval: 1.44 to 9.34; p = 0.006).

CONCLUSIONS

In patients with P/LSP-AF, PVI+PWI using the cryoballoon is associated with a significant reduction in atrial fibrillation recurrence, but similar safety, as compared with PVI alone.

Left atrial posterior wall isolation in conjunction with pulmonary vein isolation using cryoballoon for treatment of persistent atrial fibrillation (PIVoTAL): study rationale and design

BACKGROUND

There is growing evidence in support of pulmonary vein isolation (PVI) with concomitant posterior wall isolation (PWI) for the treatment of patients with symptomatic persistent atrial fibrillation (persAF). However, there is limited data on the safety and efficacy of this approach using the cryoballoon.

OBJECTIVE

The aim of this multicenter, investigational device exemption trial (G190171) is to prospectively evaluate the acute and long-term outcomes of PVI versus PVI+PWI using the cryoballoon in patients with symptomatic persAF.

METHODS

The PIVoTAL is a prospective, randomized controlled study ( ClinicalTrials.gov : NCT04505163) in which patients with symptomatic persAF refractory/intolerant to ≥ 1 class I-IV antiarrhythmic drug, undergoing first-time catheter ablation, will be randomized to PVI (n = 183) versus PVI+PWI (n = 183) using the cryoballoon in a 1:1 fashion. The design will be double-blind until randomization immediately after PVI, beyond which the design will transform into a single-blind. PVI using cryoballoon will be standardized using a pre-specified dosing algorithm. Other empiric ablations aside from documented arrhythmias/arrhythmias spontaneously induced during the procedure will not be permitted. The primary efficacy endpoint is defined as AF recurrence at 12 months, after a single procedure and a 90-day blanking period. Arrhythmia outcomes will be assessed by routine electrocardiograms and 7-14 day ambulatory electrocardiographic monitoring at 3, 6, and 12 months post-ablation.

CONCLUSION

The PIVoTAL is a prospective, randomized controlled trial designed to evaluate the outcomes of PVI alone versus PVI+PWI using the cryoballoon, in patients with symptomatic persAF. We hypothesize that PVI+PWI will prove to be superior to PVI alone for prevention of AF recurrence.

Recurrent Atrial Fibrillation After Cryoballoon Ablation: What to Expect!

Atrial fibrillation (AF) recurrence following cryoballoon ablation may occur as a consequence of pulmonary vein (PV) reconnection, which can be treated effectively by performing repeat PV isolation. Alternatively, AF recurrence can manifest in presence of bilateral antral PV isolation. In such circumstances, one may pursue catheter ablation of AF triggers, if present, or proceed with empiric posterior left atrial wall ablation. Although traditionally, focal radiofrequency ablation has been used for this, cryoballoon ablation, itself, may also be used for ablation/isolation of certain structures such as the superior vena cava, the left atrial appendage and even the posterior left atrial wall.

Differences between gap-related persistent conduction and carina-related persistent conduction during radiofrequency pulmonary vein isolation

BACKGROUND

During pulmonary vein isolation (PVI), nonisolation after initial encircling of the pulmonary veins (PVs) may be due to gaps in the initial ablation line, or alternatively, earliest PV activation may occur on the intervenous carina and ablation within the wide-area circumferential ablation (WACA) circle is needed to eliminate residual conduction. This study investigated prognostic implications and predictors of gap-related persistent conduction (gap-RPC) and carina-related persistent conduction (carina-RPC) during PVI.

METHODS AND RESULTS

Two hundred fourteen atrial fibrillation (AF) patients (57% paroxysmal, 61% male, mean age 62 ± 9 years) undergoing first contact force-guided radiofrequency PVI were studied. Preprocedural cardiac computed tomography imaging was used to assess left atrial and PV anatomy. PVI was assessed directly after initial WACA circle creation, after a minimum waiting period of 30 minutes, and after adenosine infusion. Persistent conduction was targeted for additional ablation and classified as gap-RPC or carina-RPC, depending on the earliest activation site. The 1-year AF recurrence rate was higher in patients with gap-RPC (47%) compared to patients without gap-RPC (28%; P = .003). No significant difference in 1-year recurrence rate was found between patients with carina-RPC (37%) and patients without carina-RPC (31%; P = .379). Multivariate analyses identified paroxysmal AF and WACA circumference as independent predictors of gap-RPC, whereas carina width and WACA circumference correlated with carina-RPC.

CONCLUSIONS

Gap-RPC is associated with increased AF recurrence risk after PVI, whereas carina-RPC does not predict AF recurrence. Moreover, gap-RPC and carina-RPC have different correlates and may thus have different underlying mechanisms.

Value of high-resolution mapping in optimizing cryoballoon ablation of atrial fibrillation

BACKGROUND

Unrecognized incomplete pulmonary vein isolation (PVI), as opposed to post-PVI pulmonary vein reconnection, may be responsible for clinical recurrences of atrial fibrillation (AF). To date, no data are available on the use of high-resolution mapping (HRM) during cryoballoon (CB) ablation for AF as the index procedure. The aims of this study were: - to assess the value of using a HRM system during CB ablation procedures in terms of ability in acutely detecting incomplete CB lesions; - to compare the 8-pole circular mapping catheter (CMC, Achieve) and the 64-pole mini-basket catheter (Orion) with respect to pulmonary vein (PV) signals detection at baseline and after CB ablation; - to characterize the extension of the lesion produced by CB ablation by means of high-density voltage mapping.

METHODS

Consecutive patients with drug-resistant paroxysmal or early-persistent AF undergoing CB ablation as the index procedure, assisted by a HRM system, were retrospectively included in this study.

RESULTS

A total of 33 patients (25 males; mean age: 59 ± 18 years, 28 paroxysmal AF) were included. At baseline, CMC catheter revealed PV activity in 102 PVs (77%), while the Orion documented PV signals in all veins (100%). Failure of complete CB-PVI was more frequently revealed by atrial re-mapping with the Orion as compared to the Achieve catheter (24% vs 0%, p < 0.05). A repeat ablation was performed in 8 patients (24%). In 9% of cases, the Orion catheter detected far-field signals originating from the right atrium. Quantitative assessment of the created lesion revealed a significant reduction of the left atrial area having voltage >0.5 mV. A total of 29 patients (88%) remained free of symptomatic AF during a mean follow-up of 13.2 ± 3.7 months.

CONCLUSION

Atrial re-mapping after CB ablation by means of a HRM system improves the detection of areas of incomplete ablation, characterizes the extension of the cryo-ablated tissue and can identify abolishment of potential non-PVI related sources of AF.

Laser balloon ablation for AF: A systematic review and meta-analysis

INTRODUCTION

The HeartLight laser balloon ablation system was US Food and Drug Administration approved in 2016 for the treatment of paroxysmal atrial fibrillation (AF), but there have been numerous single-center and multicenter studies published reporting its outcomes, in addition to a few randomized trials. We aimed to systematically review and synthesize currently published outcome data on AF ablation using the laser balloon ablation system.

METHODS AND RESULTS

We performed a systematic review and meta-analysis of published studies of AF ablation performed using the laser balloon ablation system. Human studies reporting acute procedural results with a minimum of 6 months follow-up were included. Outcomes of interest included acute and 12-month procedural efficacy, safety, and procedure duration. Aggregated data were analyzed with random effects models, using a Bayesian hierarchical approach. We identified 17 published manuscripts comprising a sample of 1188 patients (mean age 61 years, 80% paroxysmal). At procedure end, 98.8% of targeted pulmonary veins were successfully isolated. The pooled estimate for 12-month freedom from atrial arrhythmia without use of antiarrhythmic drugs for patients with paroxysmal AF was 74.3% (95% confidence interval [CI], 59.9% to 86.4%), and for all AF types combined was 72.9% (65.3% to 79.9%). The most commonly reported procedural complication was phrenic nerve injury (pooled incidence 2.6%; 95% CI, 1.4% to 3.9%), which resolved during follow-up in most cases.

CONCLUSION

Laser balloon ablation is highly effective at achieving pulmonary vein isolation. Although comparisons are mainly indirect, safety and 12-month efficacy compare favorably with those observed using other currently used AF ablation technologies.

Postprocedural LGE-CMR comparison of laser and radiofrequency ablation lesions after pulmonary vein isolation

INTRODUCTION

The purpose of this study was to compare the anatomical characteristics of scar formation achieved by visual-guided laser balloon (Laser) and radiofrequency (RF) pulmonary vein isolation (PVI), using late-gadolinium-enhanced cardiac magnetic resonance imaging (LGE-CMR).

METHODS AND RESULTS

We included 17 patients with paroxysmal or early persistent drug resistant AF who underwent Laser ablation; 2 were excluded due to procedure-related complications. The sample was matched with a historical group of 15 patients who underwent PVI using RF. LGE-CMR sequences were acquired before and 3 months post-PVI. Ablation gaps were defined as pulmonary vein (PV) perimeter sections showing no gadolinium enhancement. The number of ablation gaps was lower in Laser versus RF ablations (median 7 vs. 14, P  =  0.015). Complete anatomical PVI (circumferential scar around PV, without gaps) was more frequently achieved with Laser than with RF (39% vs. 19% of PVs, P  =  0.025). Fewer gaps were present at the superior and anterior left PV and posterior right PV antral regions in the Laser group, compared to RF. Scar extension into the PVs was similar in both groups, although RF produced more extensive ablation scar toward the LA body. AF recurrences at 1 year were similar in both groups (Laser 36% vs. RF 27%, P  =  1.00).

CONCLUSIONS

Compared to RF, Laser ablation achieved more complete anatomical PVI, with less LA scar extension. However, AF recurrence appears to be similar after Laser compared to RF ablation. Further studies are needed to assess whether the anatomical advantages of Laser ablation translate into clinical benefit in patients with AF.

Vagal response in cryoballoon ablation of atrial fibrillation and autonomic nervous system: Utility of epicardial adipose tissue location

Background

Mechanism and effects of vagal response (VR) during cryoballoon ablation procedure on the cardiac autonomic nervous system (ANS) are unclear. The present study aimed to evaluate the relationship between VR during cryoballoon catheter ablation for atrial fibrillation and ANS modulation by evaluating epicardial adipose tissue (EAT) locations and heart rate variability (HRV) analysis.

Methods

Forty-one patients with paroxysmal atrial fibrillation (11 with VR during the procedure and 30 without VR) who underwent second-generation cryoballoon ablation were included. EAT locations and changes in HRV parameters were compared between the VR and non-VR groups, using Holter monitoring before ablation, immediately after ablation and one month after ablation.

Results

The total EAT volume surrounding the left atrium (LA) in the VR and non-VR groups was 29.0±18.4 cm³ vs 27.7±19.7 cm³, respectively (p=0.847). The VR group exhibited greater EAT volume overlaying the LA-left superior pulmonary vein (PV) junction (6.1±3.6 cm³ vs 3.6±3.3 cm³, p=0.039) than the non-VR group. HRV parameters similarly changed following ablation in both the groups. EAT volume overlaying LA-right superior PV junction was significantly correlated with the relative changes in root-mean-square successive differences (r=−0.317, p=0.043) and high frequency (r=−0.331, p=0.034), immediately after the ablation.

Conclusions

Changes in HRV parameters following ablation were similarly observed in both the groups. EAT volume on the LA-PV junction is helpful for interpretation of VR occurrence and ANS modulation.

The quest for durable lesions in catheter ablation of atrial fibrillation - technological advances in radiofrequency catheters and balloon devices

INTRODUCTION

Atrial fibrillation is the most common cardiac arrhythmia and represents a growing clinical, social and economic challenge. Catheter ablation for symptomatic atrial fibrillation has evolved from an experimental procedure into a widespread therapy and offers a safe and effective treatment option. A prerequisite for durable PVI are transmural and contiguous circumferential lesions around the pulmonary veins. However, electrical reconnection of initially isolated pulmonary veins remains a primary concern and is a dominant factor for arrhythmia recurrence during long-term follow up. Areas covered: This article discusses the physiology of lesion formation using radiofrequency-, cryo- or laser- energy for pulmonary vein isolation and provides a detailed review of recent technological advancements in the field of radiofrequency catheters and balloon devices. Finally, future directions and upcoming developments for the interventional treatment of atrial fibrillation are discussed. Expert commentary: Durable conduction block across deployed myocardial lesions is mandatory not only for PVI but for any other cardiac ablation strategy as well. A major improvement urgently expected is the intraprocedural real-time distinction of durable lesions from interposed gaps with only transiently impaired electrical conduction. Furthermore, a simplification of ablation tools used for PVI is required to reduce the high technical complexity of the procedure.