Left Atrial Posterior Wall Isolation Research Articles

Left atrial posterior wall isolation during catheter ablation with the pulsed field ablation in patients with persistent atrial fibrillation

Abstract Background Few data are available on pulsed-field ablation (PFA) targeting left atrial posterior wall (LAPW) in persistent atrial fibrillation (PeAF) patients. Purpose We sought to explore the role of PFA in persistent AF patients beyond pulmonary vein isolation (PVI), extending the lesion set to obtain LAPW isolation. Methods We enrolled consecutive patients referred for persistent AF catheter ablation using the Farapulse PFA system at nine Italian centers. Complete 3D mapping was performed before and immediately after LAPW isolation to validate our workflow in all cases. To analyze lesions' formation and residual gaps, the line around each pair of PVs was divided into 7 distinct sections in accordance with the literature, while the roof line, the floor line, and the two longitudinal posterior wall lines were equally divided into three parts. The PW was overall divided into nine regions. This scheme has been illustrated in Figure 1, Panel A. Results Fifty patients meeting inclusion criteria were included. PVI was achieved in all 202 (100%) PVs (1 patient exhibited a left common trunk, 2 patients exhibited a right middle cardiac PV). One-hundred ninety-eight (98.0%) PVs were acutely isolated on first pass, as confirmed by both entrance and exit block on subsequent 3D-mapping with the mapping catheter. A total of 7 PV gaps were detected through 3D mapping: 4 at the RSPV, 2 at the RIPV and 1 at the LSPV. When considering LAPWI, overall LAPW ablated area was 20.0±6 cm2 with lesions being deployed with the PFA catheter maneuvered in the flower configuration from one LAPW area to another. First-pass roof area (sectors #1 to #3) block was achieved in 44 (88%), first-pass floor area (sectors #7 to #9) block in 43 (86%) and inner-area (sectors #3 to #6) block in 45 (90%). A total of 23 residual LAPW activity gaps were detected through validation using high-output pacing and 3D mapping. Remapping examples has been reported in Figure 1, panel B-C-D. Evaluation of individual segments of the LAPW via signals’ assessment from the PFA splines demonstrated an accuracy of 94.9% (437 out of 450 sectors), compared to the results of subsequent high-output pacing and 3D mapping. Following PFA consolidation in these areas, LAPW isolation was successfully achieved in all cases (100%) using PFA alone, with no need for radiofrequency touch-ups. No major procedure-related adverse events were reported. Conclusion A structured workflow with the novel Farapulse PFA system allowed for a reliable, safe, and fast LAPW isolation, as confirmed by ultra-high-density 3D mapping.

Two-year safety and effectiveness of hybrid ablation versus catheter ablation in patients with non-paroxysmal AF: mid-term results of the CEASE-AF trial

Abstract Background Hybrid Ablation for atrial fibrillation (AF) combines epicardial and endocardial ablation through a Heart Team approach to target durable, transmural isolation of the pulmonary veins (PV) and left atrial posterior wall (LAPW). While the primary efficacy endpoint at 12 months was met with a significant benefit increase for hybrid ablation, we now report the midterm durability of those results. Purpose To evaluate 24-months safety and effectiveness of Hybrid Ablation with left atrial appendage exclusion (LAAE) versus Catheter Ablation in patients with persistent AF/enlarged left atrium and longstanding persistent AF (LSPAF). Methods CEASE-AF is a prospective, multi-center, 2:1 randomized controlled trial. Eligible patients were 18-75 years of age, had symptomatic, drug-refractory persistent AF and enlarged left atrium (>4 cm) or LSPAF, and were undergoing a first ablation. Hybrid Ablation consisted of two stages: thoracoscopic epicardial radiofrequency (RF) ablation for PV and LAPW isolation and epicardial LAAE followed by endocardial ablation 91-180 days later. Catheter Ablation consisted of minimum PV isolation by endocardial RF ablation, and repeat ablation was allowed between 91-180 days. In both arms, additional lesions were permitted according to institutional practices. Effectiveness was freedom from AF/atrial flutter (AFL)/atrial tachycardia (AT) off anti-arrhythmic drugs (AAD) (except AADs not exceeding doses which previously failed) and was assessed through 48-h Holter monitoring reviewed by an independent core laboratory blinded to the study. Safety was major adverse events throughout the study, adjudicated by an independent Clinical Events Committee. Results There were 102 Hybrid Ablation and 52 Catheter Ablation patients; 26% were female, mean age was 60.7±7.9 years, mean LAD was 4.7±0.4 cm, and 19% had LSPAF with no differences between arms. The 12- and 24-month results are shown for comparison (Table). Through 24-months, effectiveness was 66.3% (63/95) in the Hybrid Arm and 33.3% (17/51) in the Catheter Arm (absolute difference 33.0% [95% CI 14.3%, 48.3%; p<0.001]). Major adverse event rates through 24-months were statistically similar at 10.8% (11/102) in the Hybrid Arm and 9.6% (5/52) in the Catheter Arm (p=1.0). Through 24-months, repeat ablations were performed in 7.4% (7/95) of the Hybrid Arm versus 37.3% (19/51) of the Catheter Arm (p<0.001), and cardioversions were performed in 14.7% (14/95) of the Hybrid Arm versus 29.4% (15/51) of the Catheter Arm (p=0.034) Conclusions: CEASE-AF demonstrated that superior effectiveness of Hybrid Ablation including LAAE versus Catheter Ablation was durable through 24-month follow-up, with 33% absolute improvement in freedom from AF/AFL/AT. Safety rates continued to be similar between arms. Three-year follow-up is ongoing.

Pulsed field ablation technology for pulmonary vein and left atrial posterior wall isolation in patients with persistent atrial fibrillation.

Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation (PeAF) undergoing left atrial posterior wall isolation (LAPWI). The Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA) prospective registry included consecutive patients referred for PeAF catheter ablation at 9 Italian centers, treated with the FARAPULSETM-PFA system. The primary efficacy and safety study endpoints were the acute LAPWI rate, freedom from arrhythmic recurrences and the incidence of major periprocedural complications. Patients undergoing pulmonary vein isolation (PVI) alone, PWI + LAPWI and redo procedures were compared. Among 249 patients, 21.7% had long-standing PeAF, 79.5% were male; mean age was 63 ± 9 years. LAPWI was performed in 57.6% of cases, with 15.3% being redo procedures. Median skin-to-skin times (PVI-only 68 [60-90] vs. PVI + LAPWI 70 [59-88] mins) did not differ between groups. 45.8% LAPWI cases were approached with a 3D-mapping system, and 37.3% with intracardiac echocardiography. LAPWI was achieved in all patients by means of PFA alone, in 88.8% cases at first pass. LAPWI was validated either by an Ultrahigh-density mapping system or by recording electrical activity + pacing maneuvers. No major complications occurred, while 2.4% minor complications were detected. During a median follow-up of 273 [191-379] days, 41 patients (16.5%) experienced an arrhythmic recurrence after the 90-day blanking period, with a mean time to recurrence of 223 ± 100 days and no differences among ablation strategies. LAPWI with PFA demonstrates feasibility, rapidity, and safety in real-world practice, offering a viable alternative for PeAF patients. LAPWI is achievable even with a fluoroscopy-only method and does not significantly extend overall procedural times.

Left atrial posterior wall isolation using pulsed-field ablation: procedural characteristics, safety, and mid-term outcomes.

Non-pulmonary vein (PV) ablation targets such as posterior wall isolation (PWI) have been tested in patients with persistent atrial fibrillation (AF). Pulsed-field ablation (PFA) offers a novel ablation technology possibly able to overcome the obstacles of incomplete PWI and concerns of damage to adjacent structures compared to thermal energy sources. Our aim was to assess procedural characteristics, safety, and mid-term outcomes of patients undergoing PWI using PFA in a clinical setting. Patients undergoing PFA-PVI with PWI were included. First-pass isolation was controlled using a multipolar mapping catheter. One hundred consecutive patients were included (median age 69 [IQR 63-75] years, 33 females (33%), left atrial size 43 [IQR 39-47] mm, paroxysmal AF 24%). Median procedure time was 66 (IQR 59-77) min, and fluoroscopy time was 11 (8-14) min. PWI using PFA was achieved in 100% of patients with a median of 19 applications (IQR 14-26). There were no major complications. Overall, in 15 patients (15%), recurrent AF/AT was noted during a median follow-up of 144 (94-279) days. PWI using PFA appears safe and results in high acute isolation rates and high arrhythmia survival during mid-term follow-up. Further randomized trials are essential and warranted.

Left atrial posterior wall isolation using pulsed-field ablation: procedural characteristics, safety, myocardial injury and short-term outcomes

Abstract Background Pulsed-field ablation (PFA) has emerged as a novel treatment strategy for patients with atrial fibrillation (AF). Among targets beyond pulmonary vein isolation (PVI), ablation of the left atrial posterior wall (LAPW) has gained increased interest in patients with persistent AF. PFA offers a novel ablation technology possibly able to overcome the obstacles of incomplete isolation and concerns of damage to adjacent structures. Purpose To assess procedural characteristics, safety, myocardial injury and short-term outcomes of patients undergoing LAPW ablation in a clinical setting. Methods Consecutive patients undergoing PFA PVI with LAPW isolation were included. Using a multi-spline PFA catheter in a flower configuration, two anchor lesions per vein extending to the LAPW were deployed. Then, the wire was pulled back into the lumen, the PFA catheter and sheath were rotated along the entire LAPW in a flower configuration thereby creating overlapping lesions as assessed by a 3D-electro-anatomical mapping system. First-pass isolation was controlled using a multipolar mapping catheter. Complications were checked with an echocardiogram, high sensitivity cardiac troponin T was measured the next day and for recurrence detection a Holter ECG was performed during follow up. Results 25 patients with persistent AF undergoing PVI were included (age 69 ± 12 years, left atrial volume index 37 ml/m2). 17 patients underwent redo-PVI with LAPW and 8 patients first time PVI with LAPW ablation. The median number of applications to perform LAPW isolation using PFA was 24 (IQR 14-28). The median procedure time was 69 min (IQR 56-81). The median LA dwell time was 59 min (IQR 49-72). The median fluoroscopy time was 10 min (IQR 8-14). First-pass isolation was achieved in 24/25 cases (95%). There were no complications. High sensitivity cardiac troponin T level post-procedurally was 951 ng/L (IQR 717-1189). Median duration of follow-up were 95 days, (IQR 84-184), AF recurrence was observed in 2 patients (8%). Conclusion LAPW ablation with PFA appears safe and results in high acute isolation rates. The optimal technique to perform LAPW ablation using PFA needs to be defined. Data on long-term outcomes are missing.

Abstract 11697: Combined-Energy Pulmonary Vein Isolation and Posterior Wall Isolation for Persistent Atrial Fibrillation: Results of a 3-year Follow-Up

Introduction: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for paroxysmal atrial fibrillation (AF), but the optimal ablation strategy for persistent AF (PsAF) remains controversial. Hypothesis: The purpose of this study was to investigate whether combined-energy cryoballoon (CB) PVI and radiofrequency (RF) left atrial posterior wall isolation (LAPWI) at index ablation of PsAF yields higher success than PVI alone. Methods: Patients with persistent AF (n = 186) who underwent catheter ablation between 2016 and 2019 at a single large academic medical center were retrospectively reviewed. Patients with congenital heart disease or prior left atrial ablation or surgery were excluded. Combined-energy ablation (n=92) consisted of CB antral PVI followed by RF roof and floor lines to achieve LAPWI, along with isolation inside the box as needed. The control group had PVI only (n=94) with either CB (n=57) or RF (n=37). The primary endpoint was 12-, 24-, and 36-month freedom from any documented atrial tachyarrhythmia over 30 seconds after a 90-day blanking period following catheter ablation, compared by Kaplan-Meier analysis. Secondary endpoints included AF burden, procedural parameters, and complications. Results: The primary endpoint of 12-month freedom from any atrial tachyarrhythmia was higher for the combined-energy group vs the control group (79.1% vs 58.2%, p = 0.009). This improvement was sustained at 24 months (63.0% vs 45.8%) and at 36 months (60.3% vs 43.1%) and remained significant after adjustment for clinical covariates (adjusted HR 0.45, 95% confidence interval 0.22-0.95; p = 0.03). There was no significant difference in procedure time or complication rates, however fluoroscopy time was shorter with combined-energy ablation (p<.001). Conclusions: In this single center experience, combined-energy CB-PVI and RF-LAPWI was associated with reduced AF recurrence compared to PVI with a single energy source.

Abstract 12943: Long-Term Ablation Outcome in Patients With Coexistent Metabolic Syndrome and Long-Standing Persistent Atrial Fibrillation Undergoing First Catheter Ablation: Results From a Propensity-Matched Population

Introduction: Procedure-outcome after catheter ablation in long-standing persistent atrial fibrillation (LSPAF) is reported to be highly variable with different ablation approaches. Metabolic syndrome (MS), a pro-inflammatory state, is also considered to be closely associated with recurrent AF. Purpose: We evaluated the long-term outcome with different ablation strategies in patients with coexistent MS and LSPAF Methods: Consecutive patients with LSPAF and MS undergoing their first catheter ablation were classified into two groups; group 1: standard ablation: PVAI extended to the entire posterior wall (PW) plus empirical isolation of superior vena cava (SVC) and group 2: standard ablation+ ablation of non-PV (NPV) triggers. Ablation strategy was based on operators’ discretion. In order to attenuate the between-group imbalance of the baseline covariates, a propensity score-matching technique was used resulting in 108 and 432 (1: 4) patients in gr 1 and 2 respectively. Arrhythmia-monitoring was performed quarterly for 1 year and biannually afterwards. Ablation success was assessed off-antiarrhythmic drugs (AAD). Results: All patients received PVAI plus isolation of left atrial PW and SVC (standard ablation). Following the standard ablation, high-dose isoproterenol challenge (25-30 μg/min for 10-15 min) was performed in group 2 (n=432) patients to identify non-PV triggers. These were detected in LAA (294, 68%), CS (315, 73%), inter-atrial septum (125, 29%) and crista terminalis (76, 17.6%). These sites were ablated using additional radiofrequency energy. Isoproterenol challenge to reveal non-PV triggers was not performed in group 1 (n=108) patients. Procedural complications included 3 (2.7%) and 6 (1.4%) groin hematomas in group 1 and 2 respectively (p=0.31). At 6 years of follow-up, the single-procedure off-AAD success rate was 19 (17.6%) in group 1 and 231 (53.4%) in group 2 (p<0.001) Conclusion: In our study patients with LSPAF and metabolic syndrome, standard ablation plus ablation of all detectable non-PV triggers during the first procedure was demonstrated to be significantly more effective in achieving long-term arrhythmia-free survival compared to standard ablation alone.

Abstract 12295: The Timing of Appearance of Untimely Dissociated Potentials After Pulmonary Vein Isolation for Atrial Fibrillation is Related to the Respiratory Phase

Introduction: Ectopic beats originating from the pulmonary vein (PV) trigger atrial fibrillation (AF). However, the mechanism and timing of Ectopic beat occurrence remain unclear. Hypothesis: The dissociated potentials (DPs) after pulmonary vein isolation (PVI) for AF are related to the respiratory phase and left atrial pressure (LAP). Methods: 93 patients underwent AF ablation under deep sedation and BiPAP ventilation. [Study1] Respiratory waveforms of 20 patients were recorded simultaneously with LAP. [Study2] In 73 patients, DPs after PVI or left atrial posterior wall (LAPW) isolation were recorded simultaneously with respiratory waveforms for 3 min, and the preceding coupling intervals (CI) of all DPs were measured. Sites with DPs frequencies <10/min were defined as rare DPs sites. In sites with DPs frequencies ≧10/min, sites where the number of DPs with CI shorter than the mean - SD of CI was greater than the number of DPs with CI longer than the mean + SD of CI were defined as short-coupling DPs sites, and long-coupling DPs sites were defined in the opposite cases. Results: [Study1] Respiratory waveforms showed fluctuations similar to LAP, and LAP increased within the respiratory interval in all patients (Fig.1). [Study2] The incidence of DPs on the left PV was lower than that on the right PV and LAPW (28 of 61 left PV 46%, 41 of 66 62%, 3 of 3 100%, P=0.0306). Additionally, the CI of DPs on the left PV was longer (3.1±5.4sec, 2.0±2.8, and 1.6±0.5, P<0.0001). The timing of appearance of DPs was not related to the respiratory phase in all DPs assessments (2126 beats during the respiratory interval and 2155 beats during the rest interval). However, inopportune DPs appeared during the specific respiratory phases: the respiratory interval for short-coupling DPs, and the rest interval for long-coupling DPs and rare DPs sites (P=0.016, Fig.2). Conclusions: The timing of appearance of untimely DPs is related to the respiratory phase and may be associated with an increase in LAP.

Symptomatic periesophageal vagal nerve injury by different energy sources during atrial fibrillation ablation.

Symptomatic gastric hypomotility (SGH) is a rare but major complication of atrial fibrillation (AF) ablation, but data on this are scarce. We compared the clinical course of SGH occurring with different energy sources. This multicenter study retrospectively collected the characteristics and clinical outcomes of patients with SGH after AF ablation. The data of 93 patients (67.0 ± 11.2 years, 68 men, 52 paroxysmal AF) with SGH after AF ablation were collected from 23 cardiovascular centers. Left atrial (LA) ablation sets included pulmonary vein isolation (PVI) alone, a PVI plus a roof-line, and an LA posterior wall isolation in 42 (45.2%), 11 (11.8%), and 40 (43.0%) patients, respectively. LA ablation was performed by radiofrequency ablation, cryoballoon ablation, or both in 38 (40.8%), 38 (40.8%), and 17 (18.3%) patients, respectively. SGH diagnoses were confirmed at 2 (1-4) days post-procedure, and 28 (30.1%) patients required re-hospitalizations. Fasting was required in 81 (92.0%) patients for 4 (2.5-5) days; the total hospitalization duration was 11 [7-19.8] days. After conservative treatment, symptoms disappeared in 22.3% of patients at 1 month, 48.9% at 2 months, 57.6% at 3 months, 84.6% at 6 months, and 89.7% at 12 months, however, one patient required surgery after radiofrequency ablation. Symptoms persisted for >1-year post-procedure in 7 patients. The outcomes were similar regardless of the energy source and LA lesion set. The clinical course of SGH was similar regardless of the energy source. The diagnosis was often delayed, and most recovered within 6 months, yet could persist for over 1 year in 10%.

Incidence, distribution, and electrogram characteristics of endocardial-epicardial connections identified by ultra-high-resolution mapping during a left atrial posterior wall isolation of atrial fibrillation.

The left atrial posterior wall (LAPW) can be a target for atrial fibrillation (AF) catheter ablation but is sometimes difficult to completely isolate due to the presence of endocardial-epicardial connections. We aimed to investigate the incidence and distribution of epicardial residual connections (epi-RCs) and the electrogram characteristics at epi-RC sites during an initial LAPW isolation. We retrospectively studied 102 AF patients who underwent LAPW mapping before and after a first-pass linear ablation along the superior and inferior LAPW (pre-ablation and post-ablation maps) using an ultra-high-resolution mapping system (Rhythmia, Boston Scientific). Epi-RCs were observed in 41 patients (40.2%) and were widely distributed in the middle LAPW area and surrounding it. The sites with epi-RCs had a higher bipolar voltage amplitude and greater number of fractionated components than those without (median, 1.09mV vs. 0.83mV and 3.9 vs. 3.4 on the pre-ablation map and 0.38mV vs. 0.27mV and 8.5 vs. 4.2 on the post-ablation map, respectively; P < 0.001). Receiver operating characteristic analyses demonstrated that the number of fractionated components on the post-ablation map had a larger area under the curve of 0.847 than the others, and the sensitivity and specificity for predicting epi-RCs were 95.4% and 62.1%, respectively, at an optimal cutoff of 5.0. Among the patients with epi-RCs after a first-pass LAPW linear ablation, areas with a greater number of fractionated components (> 5.0 on the post-ablation LAPW map) may have endocardial-epicardial connections and may be potential targets for touch-up ablation to eliminate the epi-RCs.

Left Atrial Posterior Wall Isolation with Pulsed Field Ablation in Persistent Atrial Fibrillation.

Left atrial posterior wall isolation (LAPWI) may improve rhythm control in addition to pulmonary vein isolation (PVI) in persistent atrial fibrillation (persAF) patients undergoing catheter ablation (CA). However, LAPWI may be challenging when using thermal energy sources. This study aimed to investigate the efficacy and safety of LAPWI performed by non-thermal pulsed field ablation (PFA) in CA for persAF. Consecutive persAF patients from two German centers were prospectively enrolled. There were two study cohorts: (1) the LAPWI cohort, which included PFA-guided (re-)PVI with LAPWI for first-time and/or repeat ablation procedures; and (2) a comparative persAF cohort with a PFA PVI-only approach without LAPWI for first-time ablation within the same timeframe. Patients were followed up by routine Holter ECGs. In total, 79 persistent AF patients were included in the study: 59/79 patients were enrolled in the LAPWI cohort, including 16/59 index (27%) and 43/59 repeat ablation procedures (73%). Sixteen patients (16/79; 21%) were in the PVI-only cohort without LAPWI. Of the patients treated with LAPWI, procedure time and fluoroscopy time was 91 ± 30 min and 15 ± 7 min, respectively. The acute PVI rate was 100% in all first-time ablation patients (32 patients (16 PVI only, 16 PVI plus LAPWI), 196/196 PVs). Of the 43 re-do patients in the LAPWI cohort, re-PVI was necessary in 33% (14/43) of patients (27 PVs; 1.9 PV per-patient); in 67% (29/43), all PVs were isolated, and antral ablation of the PV ostia was performed in 48% (14/29). LAPWI was performed successfully in all 59 (100%) patients of the LAPWI cohort. Two minor complications occurred. No esophageal lesion was detected in the LAPWI cohort (n = 33/59 (56%) patients underwent endoscopy). After 354 ± 197 days of follow-up, freedom from atrial arrhythmias was 79.3% (95-CI: 62-95%) in the complete LAPWI cohort (n = 14/59 (24%) on AAD: class Ic n = 9, class III n = 5). There was no difference regarding acute procedural and clinical outcome compared to the PVI-only cohort. LAPWI guided by PFA is feasible and safe in patients undergoing CA for persAF and shows favorable outcomes. In the context of durable PVI, PFA-guided LAPWI may be an effective adjunctive treatment option.

Catheter ablation using pulmonary vein isolation with versus without left atrial posterior wall isolation for persistent atrial fibrillation: an updated systematic review and meta-analysis.

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF); however, the results are suboptimal for persistent AF. The left atrial posterior wall (LAPW) is thought to be a major additional area in initiation and perpetuation of persistent AF. Therefore, adjunctive ablation of the posterior wall may reduce AF recurrence in patients with persistent AF. The objective of this study was to compare outcomes of catheter ablation in patients with persistent AF using PVI alone versus a combination of PVI and LAPW isolation. Literature search was conducted in PubMed, PubMed Central, Scopus, and Embase since inception to February 2023. Screening of studies was done via Covidence software. Risk of bias assessment was done using appropriate tools. Data extraction and a narrative synthesis were carried out accordingly. Ten studies were included, of which five were randomized controlled trials. PVI with LAPW ablation group had significantly lower recurrence of overall atrial tachyarrhythmia (OR 0.47, CI 0.32-0.70) and AF (OR 0.39, CI 0.23-0.69). In sensitivity analysis, freedom from atrial arrhythmias was noted to be significantly higher in the PVI with LAPW ablation group (OR 2.22, CI 1.36-3.64). However, there was no significant difference in occurrence of atrial flutter (OR 1.36, CI 0.86-2.14) or with periprocedural adverse events (OR 1.10, CI 0.60-1.99). LAPW ablation, in addition to PVI, significantly improves the rates of arrhythmia freedom and reduces the recurrence of overall atrial tachyarrhythmia. There was no significant difference in atrial flutter or periprocedural adverse events.

Differences in the feasibility, anatomical parameters predicting procedural difficulty, and isolation area of a left atrial posterior wall isolation using radiofrequency versus cryoballoon catheters.

The difficulty and outcome of the adjunctive left atrial posterior wall isolation (LAPWI) in patients with persistent atrial fibrillation (PersAF) may be affected by the ablation energy used. This study aimed to compare the completion rate, anatomical parameters predicting procedural difficulty, and the isolation area of a LAPWI between the use of radiofrequency (RFA) and cryoballoon ablation (CBA). We enrolled 95 and 93 patients with PersAF who underwent pulmonary vein isolation (PVI)+LAPWI using RFA (RF group) and CBA (CB group), respectively. Preoperative computed tomography was used to evaluate the anatomical features associated with an incomplete LAPWI. Post-ablation 3-dimensional maps were analyzed to quantify the isolation area. The completion rate of the LAPWI was significantly higher in the RF group than the CB group without touch-up RFA (88.4%vs. 72.0%; p=.005). Predictors of incomplete LAPWI were a longer left inferior pulmonary vein (LIPV)-esophageal distance (p<.001) for RFA and a steeper angle of the LAPW (p<.001) and longer transverse LAPW diameter (p=.016) for CBA. The isolated non-PV area with RFA or CBA alone was significantly greater in the CB group than the RF group (27.5±9.5cm2 vs. 22.9±6.9cm2 ; p<.001). The position of the esophagus at a distance from the LIPV was associated with an incomplete LAPWI using RFA, while a steeper angle of the LAPW and transverse enlargement of the LAPW were associated with that using CBA. The completion rate of the LAPWI was higher with RFA, but the isolation area outside of the PVs was greater with CBA.

Safety and Effectiveness of Adjunctive Posterior Wall Isolation in Atrial Fibrillation Patients: An Updated Meta-Analysis

As the atrial fibrillation (AF) recurrence rate remains high after pulmonary vein isolation (PVI), additional left atrial posterior wall isolation (PWI) has been studied in randomized controlled trials, however, the results are conflicting. We performed an updated meta-analysis by searching online databases for the randomized controlled trials comparing the PWI+PVI group to the PVI alone group in patients with AF. The outcomes of interest were AF recurrence, all atrial arrhythmia recurrence, and atrial flutter/atrial tachycardia (AT) recurrence. Risk ratio (RR) with a 95% confidence interval (CI) was estimated using a random effects model. A total of 1,612 patients, with 807 in the PWI+PVI group and 805 in the PVI alone group were included. The mean age was 60 (9) years, 75% were men and 71% had persistent AF. The PWI+PVI group had lower AF recurrence as compared with the PVI alone group (25% vs 32%, RR 0.73, 95% CI 0.56 to 0.96, p=0.02). There were no significant differences in all atrial arrhythmia recurrence (RR 0.90, 95% CI 0.78 to 1.04, p=0.16), atrial flutter/AT recurrence (RR 1.19, 95% CI 0.92 to 1.55, p=0.19) or adverse event rates in the 2 groups (36 vs 31; RR 1.09, 95% CI 0.67 to 1.77, p=0.73). In conclusion, adjunctive PWI in addition to PVI can be achieved with lower AF recurrence but with a nonsignificant increase in atrial flutter/AT recurrence, resulting in an overall similar rate of all atrial arrhythmia recurrence without increasing the risk of adverse events, when compared with PVI alone strategy.

Association between residual unipolar voltage and arrhythmia recurrence after left atrial posterior wall isolation for persistent atrial fibrillation.

Posterior wall isolation (PWI) combined with pulmonary vein isolation (PVI) has proven effective for persistent atrial fibrillation (AF). However, when performing PWI, creating transmural lesions with subendocardial ablation is sometimes difficult. Endocardial unipolar voltage amplitude had a higher sensitivity than bipolar voltage mapping for identifying intramural viable myocardium in the atria. In this study, we aimed to retrospectively investigate the correlation between the residual potential in the posterior wall (PW) following PWI for persistent AF and atrial arrhythmia recurrence using endocardial unipolar voltage. This was a single-center observational study. Patients who underwent PVI and PWI for persistent AF in the first procedure between March 2018 and December 2021 at the Tokyo Metropolitan Hiroo Hospital were included in this study. The patients were divided into two groups based on the presence of residual unipolar PW potentials after PWI with a cutoff of 1.08 mV and the recurrence of atrial arrhythmias was compared. In total, 109 patients were included in the analysis. Forty-three patients had residual unipolar potentials after PWI and 66 patients had no residual unipolar potentials. The atrial arrhythmia recurrence rate was significantly higher in the group with residual unipolar potential (41.8% vs. 17.9%, p = 0.003). The residual unipolar potential was an independent predictor of recurrence (odds ratio: 4.53; confidence interval: 1.67-12.3, p = 0.003). Residual unipolar potential after PWI for persistent AF is associated with recurrent atrial arrhythmias.

Efficacy and durability of posterior wall isolation with ethanol infusion into the vein of Marshall.

Ethanol infusion into the vein of Marshall (EIVOM) is expected to be an adjunctive therapy for mitral isthmus (MI) ablation. Additionally, EIVOM can widely ablate the epicardium via the branches that extend to the left atrialposterior wall (LAPW) and facilitate LAPW isolation. This study aimed to investigate the efficacy and durability of LAPW isolation with EIVOM. Our cohort consisted of 413 patients with atrial fibrillation (AF)who underwent both LAPW and MI ablations. EIVOM was first attempted in 177 (35%) patients with adequate VOMs. The VOM was infused with 5 mL of ethanol with a double coaxial guiding catheter technique. Both ablations were performed only by radiofrequency ablation (the RF group) in the remaining 236 (57%) patients. EIVOM with 5 mL of ethanol was completely achieved in 106 patients (the EIVOM group). The application duration of LAPW isolation did not differ significantly between the two groups (718 ± 276 vs. 709 ± 288 s; p = .78). LAPW debulking ablation was required in 64/106 (60%) and 176/236 (75%) patients in the EIVOM and RF groups, respectively (p < .05). However, AF- or atrial tachycardia-free survival analyses revealed no significant differences between the two groups (log-rank p = .70). Among the cases of recurrence, 17 and 38 patients underwent subsequent ablation sessions; LAPW was reconnected in 9/17 (53%) and 25/38 (53%) patients (p = .36)in the EIVOM and RF groups, respectively. EIVOM reduced the number of cases that required LAPW debulking ablation but did not improve the durability of LAPW isolation or clinical outcomes.

MP-453081-11 PULSED FIELD ABLATION OF ATRIAL FIBRILLATION: SAFE TECHNOLOGY WITHOUT COLLATERAL DAMAGE TO THE ESOPHAGUS? FINDINGS OF POST-PROCEDURAL ENDOSCOPY

Severe injuries of the esophagus causing major complications after catheter ablation (CA) of atrial fibrillation are rare. However, endoscopically detected esophageal lesions (EDEL) have been described in up to 30% after radiofrequency current energy ablation. The novel non-thermal ablation technology pulsed field ablation (PFA) allows for unique ablation of the myocardium, sparing adjacent tissues, including the esophagus. Due to the proximity of the esophagus to the left atrial posterior wall (LAPW), this study sought to investigate the safety profile of PFA after left atrial posterior wall isolation (LAWPI) in patients undergoing catheter ablation of AF. Consecutive patients underwent PFA-guided catheter ablation for AF/atrial tachycardia including LAPWI. No esophagus probe was used due to the non-thermal energy form of PFA. To rule out esophageal lesions, all patients underwent post-procedural esophageal endoscopy, possibly, the next day. In total, 44 patients were included in the study. Patients’ mean age was 68 ± 13 years, 32 of 44 patients were male (72.7%) with a median CHA2DS2-VASc Score of 2 (q1-q3:1.5-4). Of all 44 PFA procedures, 13 (29.5%) were first ablation procedures for persistent AF and 31 (70.5%) were re-ablation procedures, including AF and AT. All patients underwent PFA-guided CA with a procedure duration of 113 ± 35.2 mins and a fluoroscopy time of 14.0 ± 5.7 mins. Pulmonary vein isolation (PVI) and/or Re-PVI was performed in 32 (72.3%) of patients. Successful LAPWI with PFA was performed in all patients (100%) including one (1/44, 2.3%)% early reconnection during remapping that required additional PFA. Additional PFA (including roof line, anterior line and mitral isthmus ablation) was performed in 22/44 patients (50%). Post-procedural endoscopy was performed at a median of one day after the procedure (q1-3: 1-2 days). No ablation-associated esophageal lesion was found (0%). There was no tamponade, and only one minor groin complication (2.3%, AV fistula not requiring intervention). After pulsed field ablation, no EDEL were detected on post-procedural esophageal endoscopy. Therefore, AF ablation including left posterior wall isolation performed by pulsed field ablation seems to be safe regarding any collateral damage to the esophagus.

Efficacy and Safety Ablation Index-Guided High-Energy Linear Ablation for Persistent Atrial Fibrillation: PVI Plus Linear Ablation of Mitral Isthmus and Posterior Box Isolation.

For patients with persistent atrial fibrillation (AF), whether linear ablation should be performed remains controversial, and the efficacy and safety for ablation index (AI)-guided high-energy linear ablation of mitral isthmus (MI) and left atrial (LA) posterior box isolation is still unclear. The aims of this study were to assess the feasibility and clinical success rate of pulmonary veins isolation (PVI) combined with linear ablation of LA roof and posterior inferior (posterior wall isolation) and MI compare with the PVI-alone method in patients of persistent AF. 362 consecutive persistent AF patients were enrolled from two electrophysiology centers. A total of 200 cases were in PVI-plus group and 162 cases were in PVI-alone group. The PVI-alone group received wide circumferential isolation of both ipsilateral pulmonary veins. PVI combined with linear ablation of left atrial posterior wall isolation (LAPWI)and MI were performed in the PVI-plus group. The primary study end point was the first recurrence of an atrial arrhythmia. After 24 months, freedom from the primary endpoint was achieved in 73.5% of the patients in the PVI-plus group and 62.5% in the PVI-alone group (hazard ratio = 0.62, 95% confidence interval: 0.43-0.91, log rank p = 0.012). The procedure-related complication rates were 2.5% in PVI-plus group and 1.9% in PVI-alone group (p = 0.808). In this study, the ablation strategy of ablation (PVI plus linear ablation of mitral isthmus and posterior box isolation) was feasible and safe for persistent AF patients. Compared with the PVI-alone method, it improved outcomes in patients with persistent AF.

Posterior wall substrate modification using optimized and contiguous lesions in patients with atrial fibrillation.

Radiofrequency (RF) linear ablation at the left atrial (LA) roof and bottom to isolate the LA posterior wall using contiguous and optimized RF lesions was evaluated. Achieving isolation of the LA posterior wall is challenging as two continuous linear lesion sets are necessary. Forty consecutive patients with symptomatic atrial fibrillation (AF) and arrhythmia substrates affecting the LA posterior wall underwent posterior wall isolation by linear lesions across the roof and bottom. The cohort was divided into two groups: group 1 (20 patients) linear ablation guided by contact force (CF) only; group 2 (20 patients) guided by ablation index (AI) and interlesion distance. Bidirectional block across the LA roof and bottom was achieved in 40/40 patients. Additional endocardial RF applications in 5 patients from group 1 vs. 3 patients from group 2 resulted in posterior wall isolation in all patients. Procedure duration was almost equal in both groups. CF and AI were significantly higher in group 2 for the roof line, whereas no statistical difference was found for the bottom line. AI-guided LA posterior wall isolation led to a significantly lower maximum temperature increase. The mean AI value as well as the mean value for catheter-to-tissue CF for the roof line were significantly higher when AI-guided ablation was performed. Standard deviation in group 2 showed a remarkably lower dispersion. Ablation index guided posterior wall isolation for substrate modification is safe and effective. AI guided application of the posterior box lesion allows improved lesion formation.

Effect of epicardial fat volume on outcomes after left atrial posterior wall isolation in addition to pulmonary vein isolation in patients with persistent atrial fibrillation.

Greater epicardial adipose tissue (EAT) is related to higher recurrences after atrial fibrillation catheter ablation (AFCA). We investigated the effects of posterior wall box isolation (POBI) in conjunction with circumferential pulmonary vein isolation (CPVI) on rhythm outcomes according to varying EAT volumes among patients with persistent atrial fibrillation (PeAF). We included 1,187 patients with PeAF undergoing a de novo AFCA including those receiving CPVI alone (n = 687) and those receiving additional POBI (n = 500). The rhythm outcomes at 2 years post-AFCA were compared in subgroups stratified by the EAT volume using propensity overlap weighting. A reduced EAT volume was linearly associated with more favorable rhythm outcomes for additional POBI than for CPVI alone (P for interaction = 0.002). Among the patients with smaller EAT volumes (≤116.23 mL, the median value, n = 594), additional POBI was associated with a reduced AF recurrence risk as compared to CPVI only [weighted HR (hazard ratio) 0.74, 95% CI (confidence interval) 0.56-0.99]. In contrast, among the remaining 593 patients with greater EAT volumes (>116.23 mL), No difference was observed in the recurrence risk between the additional POBI and CPVI alone groups (weighted HR 1.13, 95% CI 0.84-1.52). Among 205 patients with repeat ablations, the POBI reconnection rate was more frequent in the large EAT group (77.4%) than in the small EAT group (56.7%, P = 0.034). While PeAF patients with a smaller EAT volume averted AF recurrence by additional POBI after CPVI, no benefit of the POBI was observed in those with a greater EAT volume.