Paroxysmal Atrial Fibrillation Ablation Research Articles

Causes for recurrence after personalized radiofrequency catheter ablation for paroxysmal atrial fibrillation and pulmonary vein reconnection site characteristics

Abstract Funding Acknowledgements Type of funding sources: None. Background Personalized pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF), tailoring the ablation index (AI) to the left atrial wall thickness (LAWT), has proven to be a highly efficient method with excellent arrhythmia free survival rates. However, the number and location of pulmonary vein (PV) reconnection sites in patients with arrhythmic recurrences after personalized PVI is not known. Purpose We aimed to analyze the PV reconnection sites and the probable causes responsible for these PV reconnections during REDO procedures after personalized atrial fibrillation (AF) ablation. Methods Consecutive patients referred for a REDO procedure, after a personalized ablation protocol for PAF, were included in the analysis. During the index procedure and using ADAS 3DTM imaging platform for segmentation, the LAWT maps were obtained from multidetector computerized tomography (MDCT) and, thereafter, imported into CARTO 3 navigation system. If reconnection of a PV was confirmed, the LAWT of the reconnection site was analyzed. Patients who lost follow-up were excluded. Results Among 251 consecutive patients who underwent personalized PVI from April 2019 to July 2021, 45 (17,9%) had recurrence of atrial tachyarrhythmias after a mean follow-up of 1,4 ± 0,8 years. Of them, 28 underwent a REDO AF ablation procedure. 26 patients (93%) had PV reconnections [17 (60%) had both right and left reconnected PVs, 5 (18%) isolated right PV reconnection and 4 (14%) isolated left PV reconnection]. Overall, there were 76 reconnection points (40 in right PVs and 36 in left PVs). Mean LAWT in right and left PV reconnection sites was 2 ± 0,8 mm and 3,1 ± 1,2 mm, respectively. Most frequent sites of PV reconnections were anterosuperior and anterior carina for RPV (accounting for 55% of reconnection points) and anterosuperior, anterior ridge and anteroinferior for LPV (75%). Only 2 PV reconnections (3%) occurred in areas with LAWT < 1 mm. Analyzing the possible causes for PV reconnections, we found a causal relationship in 20 reconnected points (26%): gaps in the ablation line (distance between two adjacent VISITAG™ > 6 mm) in 5, lower ablation index than pre-specified in the personalized ablation protocol at a given point in 15, and absence of right carina ablation line in 5 cases. Catheter instability and misinterpretation of the color-coded LAWT were the main causes of these suboptimal (under target RF dosing) ablation lesions. Conversely, among 6 patients with no gaps and optimal ablation lesions according to the pre-specified protocol, only 1 had PVs isolated during the REDO procedure. Conclusion Most of the patients with AF recurrence after a personalized AF ablation had PV reconnections. Reconnection points were more frequently present in thicker segments of both PVs. GAPS in the ablation line, suboptimal ablation lesions and catheter instability are associated with PV reconnections.

One-year follow-up after pulmonary vein isolation using pulsed field ablation for paroxysmal atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulsed field ablation (PFA) has recently been introduced as a novel routine ablation technology for paroxysmal atrial fibrillation (PAF). Only a few small clinical studies have been published on the mid- and long-term outcome. Here, we present the one-year clinical outcomes of PFA in PAF. Methods In PAF patients, PVI in conscious sedation using a steerable sheath and a pentaspline over-the-wire basket and flower PFA catheter was performed. In a subset of patients, pre- and post-ablation high-density bipolar voltage 3D maps using a pentaspline diagnostic cathter were performed. Procedural parameters, acute success, in-hospital safety and arrhythmia recurrence were assessed during one-year follow-up. Efficacy was evaluated by freedom from a ≥ 30-sec. recurrence of AF/atrial flutter (AFL)/atrial tachycardia (AT). Follow-up included 7-day Holter ECGs and/or telephonic interviews at days 90, 180 and 360 days after ablation. Results This study included a total of 108 patients (mean age 65±10 years; 44% female). Mean CHA2DS2-VASc-score was 2,3±1,7. Mean duration since first AF diagnosis was 45±63 months. Pre- and post-ablation high-density maps were performed in 36/108 (33%) of patients. Skin-to skin procedure time was 78±36 min. Fluoroscopy time and dose area product were 19±8 min and 5,56±4,64 Gy.cm2, respectively. Left atrial dwell time of the PFA catheter was 27±11 min. Acute PVI rate was 100% of PVs using PFA only. Primary adverse events occurred in 3,7% of patients (1 groin hematoma, 2 pericardial tamponades, 1 acute stroke with lethal outcome). No patients were lost during FU. During a mean FU of 346±64 days, 88 of 107 patients (82%) remained free of any symptomatic or documented AF/AFL/AT episode after a single procedure. After the 90-day blanking period, in 19 (18%) patients at least one episode of AF/AFL/AT was documented. In 14/107 (13%) patients, after 216±102 days a re-do procedure was performed. In 7/107 (7%) patients, PV reconduction was seen. In 5/107 (5%) patients, during re-do procedure clinical or induced typical or atypical flutter was treated in presence of durable PV isolation. In the remaining 2/107 (2%) patients, only clinical right atrial typical flutter was treated and no left atrial mapping was performed. Conclusions PVI using PFA in patients with a relatively long history of PAF results in a low one-year atrial arrhythmia recurrence rate. The success rate may be reduced due to the long duration since first AF diagnosis and the initial experience with PFA by the operators. PV reconduction rate during re-do procedure in a limited number of patients was 7%. There was a reasonable safety profile and it improved significantly over the course of time, indicating that the learning curve could have negatively influenced the incidence of complications. Figure: Kaplan-Meier analysis of freedom from atrial arrhythmias, including any AF/AFL/AT episode exceeding 30 sec. Not including the 3-month blanking period.

Arrhythmia mechanism dependent pulmonary vein ablation in paroxysmal atrial fibrillation.

Atrial fibrillation (AF) often requires invasive treatment by ablation to decrease symptom burden. The pulmonary veins (PV) are thought to trigger paroxysms of AF, and ablative PV isolation (PVI) is a cornerstone in AF treatment. However, incomplete PVI, where electrical conduction between the PV and left atrium (LA) is maintained, is curative of AF in a subset of patients. This implies that an antiarrhythmic effect other than electrical isolation between the PV and LA plays a role in AF prevention in these patients. We reason that the PV myocardium constitutes an arrhythmogenic substrate conducive to reentry in the patients with curative incomplete PVI. This PV substrate is amenable to ablation, even when conduction between the LA and PV persists. We propose that PV ablation strategies are differentiated to fit the arrhythmogenic mechanisms in the individual patient. PV substrate modification in patients with PV reentry may constitute a new therapeutic approach that is potentially simpler and more effective, in this subgroup of patients.

Mitral annular electrogram morphology - a balanced signal does not identify the anatomical annulus

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Background Electrogram morphology is used to identify the atrio-ventricular annuli during catheter ablation procedures with a "balanced" signal considered to represent the annuli. However, anatomical studies highlight a significantly greater mass of ventricular myocardium compared to atrial myocardium at the valve plane suggesting the correct electrical signature of the anatomical annulus may not be a balanced signal. Purpose To identify the relationship between atrial and ventricular electrogram components at the anatomically defined mitral valve annulus. Methods Mapping of the mitral annulus was performed in patients undergoing ablation for paroxysmal atrial fibrillation. Following femoral venous access and trans-septal puncture, left atrial anatomy was defined using rotational angiography performed using a 100ml contrast injection 4 seconds prior to X-ray acquisition, during rapid pacing and apnoea while covering 200 degrees at 40 degrees/s. A SmartTouch SF ablation catheter (Biosense Webster) was advanced into the left atrium and used to record intracardiac electrograms at four positions around the mitral annulus and at five predetermined levels ranging from ventricular to atrial (Figure, panel A). Data analysis was performed using OpenEP (https://openep.io). For each electrogram, the distance to the mitral valve plane and the amplitudes of atrial and ventricular electrogram components were calculated (Figure, panel B and C). Mean electrogram component amplitudes were calculated including all points recorded within ±2.5mm of the mitral valve plane. For each patient, a linear regression model was fitted and used to identify the atrial/ventricular ratio at the anatomically defined mitral valve annulus (Figure, panel D). Results The protocol was completed in 9 patients, including analysis of 240 atrial or ventricular electrogram components. Within ±2.5mm of the anatomically defined mitral valve annulus, the mean recorded amplitudes of atrial and ventricular electrogram components was 0.15±0.17mV and 1.35±1.27mV, respectively (A/V ratio 1:9). Using the linear regression model, the ventricular electrogram component was calculated to be 16.5±11.6 times greater in amplitude than the atrial electrogram component at the mitral valve plane (A/V ratio 1:16). The use of a balanced signal to identify the mitral valve annulus resulted in a positional error of -7.9±9.5mm (i.e. identifying a level which is approximately ~8mm too "atrial" compared to the anatomically defined annulus). Conclusion The conventional use of a "balanced" electrogram signal does not identify the anatomical mitral valve annulus. An atrial/ventricular electrogram ratio between 1:9 and 1:16 best approximates the mitral valve annular plane determined by left atrial rotational angiography. These findings have relevance in target site selection for an accessory pathway and the ventricular extent of linear ablation at the mitral isthmus.

Very high power- short duration radiofrequency ablation in patients with congenital heart disease and atrial fibrillation: safety and outcome

Abstract Funding Acknowledgements Type of funding sources: None. Background It has been shown recently that ablation of paroxysmal and persistent atrial fibrillation (AF) using very high-power-short duration (vHPSD) ablation protocol is safe and effective. Data for vHPSD ablation protocol in adult patients with congenital heart disease (ACHD) are lacking. We searched our database for ACHD patients undergoing AF ablation using vHPSD ablation regarding periprocedural safety and outcome. Methods The data of 62 consecutive ACHD patients with mild (n=43; 69.4%), moderate (n=15; 24.2%) or complex (n= 4; 6.4%) CHD were analysed (Table 1 ). Mean age was 60,43 ± 12,7 years ( 46% male) with a Cha2ds2-VASc2 Score median of 2. Patients were diagnosed with paroxysmal AF (n= 24; 38%) or persistent AF (n= 38; 61%). In 6 patients (9,6 %), a previous conventional pulmonary vein isolation (PVI) had been performed. Settings used for vHPSD ablation were 70 W/5-7 s or 60 W/7-10 s using irrigated-tip catheters. Circumferential PVI was performed in all 62 patients; in 30 patients (48%) additional substrate ablation was performed. The 30-day incidence of adverse events was analyzed and patients followed-up in regular visits at our outpatient clinic using repetitive 7 days Holter ECGs every 3 months. Results No adverse events such as cardiac tamponade, pericardial effusion >10mm, transient ischemic attack/stroke, atrio-esophageal fistula, cardiac arrest or death occurred. Vascular access complications were detected in 7/62 patients (11%), including 4 patients with a need of intervention (surgical n=2, thrombin injection n=2). Complete PVI was performed in all patients (mean procedure time 129 ± 42min, mean fluoroscopy time 9,09 ± 5.44 min. Radiofrequency (RF) time was 127.27 ± 7,25 min (111,43 ± 27,83 min PVI only, 148,76 ± 46,07 min PVI + substrate ablation). After a mean follow up of 249 days, freedom of any atrial arrhythmia off antiarrhythmic drugs (AAD) after a single ablation procedure was present in 26/47 patients (55.3%). Success rate was significantly higher in patients with paroxysmal AF (n=16/18; 88%) compared to patients with persistent AF (n=10/29; 34.5%; p< 0.001; Figure 1) Conclusion: In this first study using vHPSD in ACHD patients of variable complexity with paroxysmal or persistent AF, the technique was safe and effective. Major periprocedural complications were rare and limited to vascular access problems. No vHPSD ablation modality-related complications occurred. vHPSD was fast in all patintes regardless of CHD complexity. Results in the paroxysmal CHD group were excellent and encouraging for persistent AF.

Left atrium substrate and wave speed mapping using Omnipolar technology in patients undergoing paroxysmal atrial fibrillation catheter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background The new Ensite X Cardiac Mapping (Abbott) system, with the introduction of Omnipolar technology (OT), provides three-dimensional information on voltage, direction of activation and conduction velocity of endocardial potentials, regardless of catheter orientation. OT thus enables the creation of more defined voltage maps and a wave speed map, a color map encoded by the numerical value of conduction velocity. Purpose We aimed to evaluate the feasibility and reliability of left atrium (LA) substrate and wave speed mapsperformed with OT in patients undergoing pulmonary vein isolation of paroxysmal atrial fibrillation (AF). Methods We included 39 patients undergoing catheter ablation for paroxysmal AF with the new Ensite X Cardiac Mapping System at five Italian Institution. In all patients the left atrium (LA) was mapped with the Advisor HD Grid catheter (Abbott). A sinus rhythm high-density voltage map and wave speed map were obtained and analyzed to compare low-voltage areas and to identify high conduction velocity areas. Results Thirty-nine pts were included in this analysis (61±10 years, 64% male, 68% with paroxysmal AF, CHA2DS2-VASc = 1.6±1.1, left atrial diameter = 46±9 mm, left ventricle ejection fraction 63±4%). The voltage maps were obtained by acquiring and, after point validation, analyzing significantly more points in the OT analysis than in the bipolar analysis (11455±8833 vs 8186±5826 and 2611±1728 vs 1753±1324, respectively; p < 0.001). Low-voltage area (< 0.05 mV) was significantly less extensive using OT (low-voltage OT area 8.9 cm2 [5.8; 24.2] vs low-voltage bipolar area 10.8 [6.4; 31.4]; p < 0.05), Fig 1. Considering wave speed maps, the pulmonary veins showed significantly higher values than the atrial values (LSPV: 2.89 ms/s ± 1.99; LIPV 2.86 ms/s ± 1.78; RSPV 3.31 ms/s ± 2.07; RIPV 2.86 ms/s ± 1.96; LA 1.67 ms/s ± 0.80; p< 0.001) while, in the atrium, the area of greatest speed was located on the roof (2.35 ms/s ± 1.53; p 0.02) almost drawing a bundle from the RSPV to the LA appendage that could coincide with the anatomical Bachmann’s bundle location, Fig 2. Conclusion OT makes it possible to obtain voltage maps by analyzing a larger number of points and providing a better substrate definition. Wave speed mapping is a promising new map type, allowing characterization and identification of high velocity areas. Further studies are needed to assess the impact of this new technology on procedural workflow and clinical outcome.

Cardiac Troponin I kinetic after pulmonary vein isolation for atrial fibrillation ablation with pulsed-field ablation and cryo-energy

Abstract Funding Acknowledgements Type of funding sources: None. Background Previous studies have demonstrated that cardiac biomarkers elevate after both cryoballoon (CB) and radiofrequency atrial fibrillation (AF) ablation, depending on the amount of energy delivered and the site of ablation. To date no comparison has been made between these thermal energy source and a novel non-thermal pulsed-field ablation (PFA) technology based on cells electroporation. Purpose Our analysis aims to compare acute myocardial injury through cardiac troponin I variation after pulmonary vein isolation (PVI) performed with different technologies (PFA vs CB). Methods All consecutive patients undergoing paroxysmal AF ablation with CB and PFA at our center from July to November 2022 were included. Protocol-directed cryoablation (CBA) was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation was not available. A standard PFA protocol-directed PVI was applied using 2kV with eight applications per vein (four applications each in the basket and flower poses). The ablation endpoint was PVI as assessed by entrance and exit block. Pre- and post-procedure samples of cardiac troponin I (CTpI) were collected before CBA/PFA and at 24h after ablation. Only patients with normal baseline values for myocardial injury were included. Results A total of 71 patients met inclusion criteria and were included in this analysis. The CBA group consists of 50 (70%) patients and the PFA group comprises 21 (30%) patients. The number of CBA applications to reach PVI was 5.0±1.4 and the number of PFA applications to achieve PVI was 32±4. All (100%) patients were in sinus rhythm at the time of the procedure. Evaluating the kinetic of CTpI, baseline values were homogeneous between CBA and PFA groups (p=0.979) whereas CTpI values significantly rose from baseline (7±2 ng/L) to 24h (8979±3691 ng/L, p<0.0001) and were significantly different between groups after CBA/PFA (8148±3311 ng/L for CBA vs 11900±7143 ng/L for PFA, p=0.0056). PVI was achieved in all patients (100%) using only CB or PFA. No major procedure-related adverse events were reported. Conclusion Our preliminary results showed that cardiac troponin I enzyme level increased after PVI by means of both cryoballoon and pulsed-field ablation and were higher after cellular electroporation by PFA than cryoablation.

High-Frequency Low-Tidal Volume Ventilation Improves Long-Term Outcomes in AF Ablation: A Multicenter Prospective Study

BackgroundHigh-frequency, low-tidal-volume (HFLTV) ventilation is a safe and simple strategy to improve catheter stability and first-pass isolation during pulmonary vein (PV) isolation. However, the impact of this technique on long-term clinical outcomes has not been determined. ObjectivesThis study sought to assess acute and long-term outcomes of HFLTV ventilation compared with standard ventilation (SV) during radiofrequency (RF) ablation of paroxysmal atrial fibrillation (PAF). MethodsIn this prospective multicenter registry (REAL-AF), patients undergoing PAF ablation using either HFLTV or SV were included. The primary outcome was freedom from all-atrial arrhythmia at 12 months. Secondary outcomes included procedural characteristics, AF-related symptoms, and hospitalizations at 12 months. ResultsA total of 661 patients were included. Compared with those in the SV group, patients in the HFLTV group had shorter procedural (66 [IQR: 51-88] minutes vs 80 [IQR: 61-110] minutes; P < 0.001), total RF (13.5 [IQR: 10-19] minutes vs 19.9 [IQR: 14.7-26.9] minutes; P < 0.001), and PV RF (11.1 [IQR: 8.8-14] minutes vs 15.3 [IQR: 12.4-20.4] minutes; P < 0.001) times. First-pass PV isolation was higher in the HFLTV group (66.6% vs 63.8%; P = 0.036). At 12 months, 185 of 216 (85.6%) in the HFLTV group were free from all-atrial arrhythmia, compared with 353 of 445 (79.3%) patients in the SV group (P = 0.041). HLTV was associated with a 6.3% absolute reduction in all-atrial arrhythmia recurrence, lower rate of AF-related symptoms (12.5% vs 18.9%; P = 0.046), and hospitalizations (1.4% vs 4.7%; P = 0.043). There was no significant difference in the rate of complications. ConclusionsHFLTV ventilation during catheter ablation of PAF improved freedom from all-atrial arrhythmia recurrence, AF-related symptoms, and AF-related hospitalizations with shorter procedural times.

Performance of the REAL-AF Same-Day Discharge Protocol in Patients Undergoing Catheter Ablation of Atrial Fibrillation

BackgroundSame-day discharge (SDD) after catheter ablation of atrial fibrillation (AF) has been widely adopted. Nevertheless, planned SDD has been performed by using subjective criteria rather than standardized protocols. ObjectivesThe goal of this study was to determine the efficacy and safety of the previously described SDD protocol in a prospective multicenter study. MethodsUsing the REAL-AF (Real-world Experience of Catheter Ablation for the Treatment of Paroxysmal and Persistent Atrial Fibrillation) SDD protocol eligibility criteria (stable anticoagulation, no bleeding history, left ventricular ejection fraction >40%, no pulmonary disease, no procedures within 60 days, and body mass index <35 kg/m2), operators prospectively determined whether patients undergoing ablation of AF were candidates for SDD (SDD vs non-SDD groups). Successful SDD was achieved if the patient met the protocol discharge criteria. The primary efficacy endpoint was the success rate of SDD. The primary safety endpoints were readmission rates as well as acute and subacute complications. The secondary endpoints included procedural characteristics and freedom from all-atrial arrhythmias. ResultsA total of 2,332 patients were included. The REAL-AF SDD protocol identified 1,982 (85%) patients as potential candidates for SDD. The primary efficacy endpoint was achieved in 1,707 (86.1%) patients. The readmission rate for SDD vs non-SDD group was similar (0.8% vs 0.9%; P = 0.924). The SDD group had a lower acute complication rate than the non-SDD group (0.8% vs 2.9%; P < 0.001), and there was no difference in the subacute complication rate between groups (P = 0.513). Freedom from all-atrial arrhythmias was comparable between groups (P = 0.212). ConclusionsIn this large, multicenter prospective registry, the use of a standardized protocol showed the safety of SDD after catheter ablation of paroxysmal and persistent AF. (Real-world Experience of Catheter Ablation for the Treatment of Paroxysmal and Persistent Atrial Fibrillation [REAL-AF]; NCT04088071)

PO-01-007 GEOGRAPHICAL REGIONAL VARIATION IN PATIENT CHARACTERISTICS AND OUTCOMES DURING ABLATION OF PAROXYSMAL ATRIAL FIBRILLATION IN THE REAL-AF REGISTRY

Geographical regional variations in the use of catheter ablation for atrial fibrillation ablation have been described. We hypothesized that such differences, as well as other demographic regional variations, may have a significant impact on the baseline characteristics and outcomes of patients undergoing atrial fibrillation ablation. We sought to describe geographic variation in the characteristics and outcomes of patients who underwent catheter ablation for paroxysmal atrial fibrillation as part of the REAL-AF registry. REAL-AF is a prospective observational registry of patients undergoing ablation for atrial fibrillation. Baseline comorbidities, complications and arrhythmia free survival were determined and compared across paroxysmal atrial fibrillation patients in four US regions: South, North-east, Mid-west, and West. Categorical variables were compared using chi squared test. Continuous variables were assessed by ANOVA followed by Tukey HSD test. Kaplan Meier Curves were constructed to compare arrhythmia free survival. A total of 2745 patients underwent catheter ablation for paroxysmal atrial fibrillation as part of the REAL AF registry, and 1061 patients from 12 centers had long-term follow-up data. Patients enrolled from centers in the South had a comparatively greater number of comorbidities (2.1 ± 1.4) when compared to their counterparts in the Midwest ( 1.8 ± 1.5), West ( 1.6 ± 1.4), and Northeast ( 1.4 ± 1.0, comparison to mid-west also significant). CHADS2VASC scores echoed these findings. More specific findings are highlighted in the baseline characteristics table. Procedural complications were similar across regions (p> 0.05). There was significant regional variation in long-term outcomes with Southern patients having the best arrhythmia free survival despite the presence of higher comorbidities (see figure). Significant regional variation exists in baseline characteristics and outcomes of patients undergoing ablation for atrial fibrillation in the REAL AF registry. Higher comorbidities were noted in patients enrolled from the South, but this did not translate to worsened outcomes.

PO-01-198 DOUBLE TROUBLE: HIGHER COMPLICATIONS AND INCREASED PROCEDURE TIMES WITH DOUBLE TRANSEPTAL PUNCTURE

The three main techniques for transeptal access during catheter ablation (CA) of atrial fibrillation (AF) are double transeptal puncture (DTP), single transeptal puncture (STP), and single transeptal puncture with double access (STP-DA). It is unclear which of these techniques is the safest and most effective. To evaluate the periprocedural outcomes of DTP, STP, and STP-DA in patients undergoing first-time catheter ablation for paroxysmal atrial fibrillation. Consecutive patients undergoing first-time catheter ablation for paroxysmal AF performed by 67 operators in 43 centers were prospectively enrolled in the REAL-AF registry. The primary outcomes were procedural time and periprocedural complications. A total of 2,289 patients were included in the study. 379 underwent DTP, 612 underwent STP, and 1298 underwent STP-DA. The mean age was 65±10 years, 55% were male, the mean BMI was 30±7 kg/m2, and the mean CHA2DS2VASc score was 2.5±1.52 without statistically significant differences among the groups. Procedural time was 137.9±72.5 min. for DTP, 97.7±39.1 min. for STP, and 74±28.9 min. for STP-DA, with significant differences in ANOVA and independent t-test (p<0.001). Similarly, fluoroscopy time was 2.5±3.0 min for DTP, 1.8±2.0 min for STP, and 0.9±1.1 min for STP-DA, with significant differences in ANOVA and independent t-test (p<0.01). The complication rate was significantly higher in DTP compared to STP (1.3% vs. 0.2% | p=0.033), while there was no difference when comparing STP to STP-DA (1.3% vs. 0.7% | p=0.18). The use of DTP is associated with increased procedural time compared to STP or STP-DA. It is also associated with a significantly higher complication rate compared to STP. Interestingly, STP-DA was associated with a significant reduction in procedural times compared to STP, potentially due to the elimination of catheter exchange during the procedure.

A randomized controlled trial of pulsed field ablation versus standard-of-care ablation for paroxysmal atrial fibrillation: The ADVENT trial rationale and design.

Pulmonary vein isolation (PVI) is an effective treatment for paroxysmal atrial fibrillation (PAF). However, potential complications can occur due to the propagation of thermal energy into nontarget tissues adjacent to the targeted myocardium. Pulsed field ablation (PFA) is a novel ablation modality with the potential for preferential myocardial tissue ablation to minimize damage to collateral cardiac structures. A multielectrode pentaspline catheter has demonstrated safety and efficacy in treating PAF in single-arm, first-in-human studies. The study sought to perform a randomized clinical trial to directly compare this PFA catheter with conventional ablation-either radiofrequency or cryoballoon ablation. The ADVENT (Randomized Controlled Trial for Pulsed Field Ablation versus Standard of Care Ablation for Paroxysmal Atrial Fibrillation) trial is a multicenter, prospective, single-blind, randomized controlled trial to compare PVI using PFA vs conventional thermal ablation for drug-resistant PAF-with each site employing either (but not both) cryoballoon or radiofrequency ablation as a control condition. The sample size is adaptively determined based on Bayesian statistical methods. All patients will undergo PVI, and be followed for 12 months. The primary effectiveness endpoint is a composite of acute procedural success and freedom from any documented atrial arrhythmia recurrence, repeat ablation, or use of antiarrhythmic drugs after a 3-month postablation blanking period. The primary safety endpoint is a composite of defined acute and chronic device- and procedure-related serious adverse events. Both primary endpoints will be evaluated for noninferiority of the novel PFA system compared with standard-of-care thermal ablation. By providing objective, comparative data, this study aims to scientifically determine whether the pentaspline PFA catheter is safe and effective for PVI ablation to treat drug-resistant PAF.

PO-02-186 DIFFERENCES IN PATIENT CHARACTERISTICS AND ATRIAL FIBRILLATION ABLATION OUTCOMES BETWEEN HIGH VOLUME ACADEMIC AND COMMUNITY CENTERS- A COMPARISON FROM THE REAL-AF REGISTRY

It is unknown whether systematic differences exist in atrial fibrillation (AF) patient characteristics or ablation outcomes between high volume centers from the community or academia. We sought to compare the baseline characteristics, procedural parameters, and outcomes for radiofrequency (RF) ablation of paroxysmal AF performed at community and academic centers in the REAL-AF registry. REAL-AF is a prospective observational registry of high volume AF ablation operators with low fluoroscopy use from both academic and community practices. Using registry data, we compared baseline comorbidities, treatment choices, and arrhythmia free survival between community and academic centers, considering only paroxysmal atrial fibrillation. A total of 853 ablations were performed at community programs and 159 at academic programs. Patients enrolled in the community were more likely to have hypertension (62.8% vs 50.6%), obstructive sleep apnea (46.8% vs 34.6%), vascular disease (18.6% vs 5.1%), and a higher CHADSVASC score (2.5±1.53 vs 2.1±1.32 p<0.05 all - Table 1). Conversely, patients at academic centers had larger mean left atrial size (99.45±36.84 vs 83.75±24.12 cm3 p < 0.05). Patients at academic centers were more likely to receive oral anticoagulation pre-ablation (94.2% vs 85.5% p = 0.03). Procedurally, community centers in REAL-AF were more efficient with lower mean procedure time, RF ablation time and fluoroscopy use (p < 0.05 for all - Table 1). There was similar lesion set choices for the procedure. First pass isolation was achieved similarly between community and academic centers. Ablations in the community had a lower recurrence of -atrial fibrillation (16.2% vs 25.5% p = 0.02 ), however this difference was no longer significant on multivariate analysis accounting for confounders such as left atrial size. In the REAL AF registry, patients undergoing ablation of paroxysmal atrial fibrillation at community centers had more comorbidities but smaller left atrial size when compared to academic centers. High volume community providers were more efficient and used less fluoroscopy. Long-term outcomes were similar after accounting for differences in baseline characteristics.

PO-04-042 GENDER DIFFERENCES IN CLINICAL OUTCOMES AFTER PULSED FIELD ABLATION OF ATRIAL FIBRILLATION: INTERIM ANALYSIS OF THE MANIFEST-PF EFFICACY REGISTRY

Prior studies have shown that atrial fibrillation (AF) ablation with conventional thermal ablative modalities, radiofrequency (RF) or cryo, is associated with a higher risk of complications in women compared with men, and a lower success rate of freedom from AF recurrences. Pulsed-field ablation (PFA) is a novel AF ablation energy modality which, in first-in-human clinical trials, has demonstrated preferential myocardial tissue ablation with a unique safety profile. We performed an interim analysis of the MANIFEST-PF registry to explore gender differences in real-world outcomes after PFA of AF. MANIFEST-PF is a retrospective patient-level registry from the first 23 European centers performing clinical PFA procedures, including all consecutive patients who received first-ever ablation for paroxysmal or persistent AF between March to December 2021 using the pentaspline PFA catheter (Farawave, Farapulse-Boston Scientific Inc). We compared baseline and procedural characteristics, and clinical outcomes between men and women. The efficacy endpoint was freedom from atrial arrhythmia (AF/atrial flutter/atrial tachycardia) recurrence ≥30 seconds after a 3 month-blanking period. Safety endpoints included major/minor adverse events (AEs <7 days post-procedure). Binary logistic regression model was created using -- Age, CAD, CHF, Sleep apnea, LVEF, LAD, Non-parox AF, Female, diabetes, HTN and stroke/TIA. Of the 1,332 AF pts who underwent an AF ablation, 454 (34%) were female. Woman, compared to men, were older (67±10 vs 62±11 yrs) and had more paroxysmal AF (72% vs 61%), but less comorbidities such as coronary disease, heart failure and sleep apnea. (Figure A) Following ablation, there was no significant difference in major (2.6% vs 1.1%, p=0.14) or minor (3.3% vs 4.4%, p=0.18) AEs between groups. Multivariable analysis showed that women (Odds ratio 4.1, 95% CI [1.21–13.78], p=0.02) were more likely to have a higher risk of acute major AEs. After a mean follow-up of 196 days, there was no difference in recurrence of atrial arrhythmia (14.5% vs 18%, p=0.14) or redo-ablations (5.1% vs. 7.7%, p=0.07) between women and men, respectively, even after adjusting for the type of AF (ie, PAF vs PerAF). (Figure B) As compared with men, women undergoing PFA to treat AF experience more acute major procedural complications, though the overall rate of complications was low with PFA. On the other hand, women have a similar success rate of freedom from recurrent atrial arrhythmias.

QI-452785-1 SAME-DAY DISCHARGE AFTER CATHETER ABLATION OF ATRIAL FIBRILLATION IN A MULTICENTER REGISTRY (REAL-AF)

Same-day discharge (SDD) after catheter ablation of atrial fibrillation (AF) has become increasingly common, improving healthcare resource utilization, reducing procedure-related costs, and possibly increasing patient satisfaction. Nevertheless, most data regarding the safety of SDD originate from cohorts, including patients from a limited number of centers. To determine the safety and efficacy of our previously described protocol for SDD in a prospective analysis and identify patients’ characteristics that render them ineligible to implement this strategy. The REAL-AF registry is a multi-center registry. Based on the protocol eligibility criteria (CHA2DS2-VASc score ≤3, stable anticoagulation, absence of bleeding history, no interventional procedures within 60 days of ablation, and BMI < 35 kg/m2), operators prospectively determined whether or not patients undergoing ablation for paroxysmal or persistent AF were candidates for SDD (SDD and the non-SDD groups). After the procedure, SDD occurred if the patient fulfilled the protocol discharge criteria (stable hemodynamics, no evidence of complications, ability to ambulate). The primary efficacy endpoint was to describe procedural outcomes predicted by the protocol, including the occurrence of procedure-related complications in the non-SDD group. The secondary endpoint was to determine the percentage of patients successfully discharged as planned (successful SDD [S-SDD] vs. unsuccessful SDD [U-SDD]). A total of 2328 patients were included, out of which 1977 (84.9%) fulfilled the eligibility criteria for SDD (SDD group), and 351 (15.1%) compounded the non-SDD group. S-SDD occurred in 85.9% (1699/1977) of patients. The U-SDD group underwent longer ablation (23.2±13.9 vs. 21.1±10.8; p= 0.005) and procedure time (98±55 vs. 92±43; p= 0.038). Likewise, the non-SDD group underwent more procedural (113±54 vs. 93±45; p< 0.001) and ablation time (24.5±12.2 vs. 21.4±11.3; p< 0.001). In the non-SDD, as determined by our protocol, the rate of acute complications was higher [4.6% (16/351 vs. 1.7% (35/1977 vs); p< 0.001]. The reported complications were mainly pericarditis and vascular access complications. In a large multicenter registry, using a standardized protocol not only identified a high proportion of patients suitable for SDD but also predicted procedural outcomes and patients with a high risk of complications. Interestingly, patients selected by the protocol for SDD presented a low rate of procedural complications.

PO-01-098 HIGH FREQUENCY LOW TIDAL VOLUME VENTILATION (HFLTV) COMPARED TO JET VENTILATION AND STANDARD VENTILATION (SV) IMPROVES FIRST PASS ISOLATION (FPI) AND PROCEDURAL EFFICIENCY (PE) IN THE REAL AF REGISTRY

The REAL-AF registry is a prospective multi-center registry designed to obtain real-world clinical experience of atrial fibrillation (AF) ablations. HFLTV and JET ventilation have both been shown to improve acute procedural efficacy and catheter stability compared to SV. FPI has been shown to be a predictor of long-term freedom from AF. To date, results of HFLTV and JET have not been directly compared. To report FPI and PE metrics during paroxysmal (PAF) and persistent atrial fibrillation (PsAF) ablation utilizing HFLTV, JET, and SV in the REAL AF registry. Retrospective cohort study of pts in the REAL AF registry with history of PAF and PSAF undergoing index ablation procedure (proc) across 44 sites. A total of 3995 patients are included from Jan 2018 through Oct 2022. There are 1,970 (49%) patients in the SV group, 1,799 (45%) in the HFLTV group, and 229 (5.7%) in the JET group. Chi-square tests were used to analyze categorical variables and t-tests for continuous variables. To test differences of mean values in continuous variables, analysis of variance (ANOVA) was employed. Post hoc Tukey’s HSD tests were employed to identify the specific pairs that had statistically significant differences in means. The HFLTV (45.3%) and JET(53.5%) pts were more likely to have sleep apnea compared to SV (43.3%) group (p=0.012). The HFLTV (2.9) and JET (3.02) pts had higher CHADSVasc scores than the SV (2.55) group (p=<0.001). Mean procedure time was lower in HFLTV (86.3) compared to JET (122.4) and SV (101) groups (p<0.001). The JET (16.7) cases had longer mean time to extubation than HFLTV (13) and SV (13.4) groups (p <0.001). The HFLTV (13.3) had lower mean PV RF times than JET(17.5) and SV (18.5) groups (p=<0.001). The HFLTV (19.3) had lower mean total RF times than JET(23.2) and SV(24.8) groups (p<0.001). Proc with HFLTV (87.9%) and JET (85.8%) were more likely to achieve FPI of left PVs compared to SV (83.5% p=0.001). FPI of the right PVs was more likely with JET (83.3%) compared to HFLTV (77.6%) and SV (71.4% p <0.001 ). Both HFLTV and JET procedures had higher FPI rates compared to SV, likely indicating more effective lesion formation. JET cases took longer than HFLTV and required more ablation time. This study is limited by being retrospective and uncontrolled. Whether acute procedural success as measured by FPI translates into long-term clinical success is yet to be determined.

PO-01-191 CARDIAC NERVE ACTIVITY DURING APNEA IN ATRIAL FIBRILLATION PATIENTS

The cardiac autonomic system (CAS) is involved in the pathogenesis of atrial fibrillation (AF), particularly in AF’s association with sleep apnea. The human CAS response to apnea has not been characterized. The feasibility of CAS nerve recordings in humans has not been established. To record apnea-induced CAS nerve activity in humans before and after AF ablation. Six patients (age 70.8 ± 12.2 years; 66.7% men) undergoing paroxysmal (2/6) or persistent (4/6) AF ablation were enrolled in this study under an IRB-approved protocol. Under ultrasound and fluoroscopy guidance, multipolar catheters (EPR800, Millar, Houston, or EP star, Baylis, Toronto, CA) were placed in the stellate ganglion (SG) bilaterally and in the vein of Marshall (VOM). Nerve signals were recorded using a head stage digitizer via customized adapters and sampled at 30 kHz with a Grapevine recording system (Ripple, Salt Lake City, UT). Under general anesthesia, monitoring of arterial blood pressure, peripheral O2 (pO2) saturation and end-tidal CO2, apnea was induced by stopping ventilation until pO2 reached 90%, after which ventilation resumed. Four apneas were preformed– 2 before and 2 after ablation. Spike2 software (Cambridge Electronic Design, Cambridge, UK) was used to resolve nerve spike morphology, automatically discern spike morphologies, and quantify nerve activity. In all 6 patients, we observed increased VOM local nerve activation triggered by apnea, which were abolished by VOM ethanol infusion and AF ablation. We observed SG activation triggered by apnea in 2 out of 6 patients. In both cases SG activation were exaggerated after VOM ethanol infusion and AF ablation (Figure). In 4/6 SG activations were not recordable. CAS recording in humans undergoing AF ablation is feasible albeit inconsistent in the SG. Apnea produces activations of the CAS. VOM ethanol eliminates local nerve responses to apnea.

PO-01-041 COMPARISON OF DIFFERENT POWER SETTINGS (40W VS 50W) IN HIGH-POWER SHORT-DURATION RADIOFREQUENCY ABLATION FOR PAROXYSMAL ATRIAL FIBRILLATION: ACUTE AND LONG-TERM CLINICAL OUTCOMES

The REAL-AF registry is a prospective multi-center registry designed to obtain real-world clinical experience of atrial fibrillation (AF) ablations. While pulmonary vein isolation (PVI) can be performed successfully with various power settings, there has been a recent surge of interest in delivering higher power short duration (HPSD) lesions using 40W-50W through the irrigated tip ablation catheters. However, the ideal power setting to deliver HPSD lesions is unknown. Compare the procedural characteristics, safety and long-term all-atrial arrhythmia recurrence between patients undergoing HPSD radiofrequency ablation either using 40W or 50W. We analyzed the data derived from subjects in the Real-AF registry from January 2018 through May 2021. The patients enrolled underwent a first-time catheter ablation for paroxysmal AF with a minimum follow-up of 12 months. The sample of patients was dichotomized in procedures using either HPSD 50 W or HPSD 40 W of power, with a target ablation index (AI) in the anterior wall of 500-550 and posterior wall of 400 for both groups. We used unadjusted bivariate analyses to explore the relationship between power delivery, patient characteristics and procedural and 12-month clinical outcomes. A total of 385 patients were included in the analyses. There were no significant differences in patient characteristics between groups (Table 1). The HPSD 50W group had significantly shorter RF time (18.69 vs. 29.21, p<0.001) and procedural time (77.72 vs. 99.98, p<0.01) when compared to the LPLD group. There were no statistically significant differences between HPSD 50 W and HPSD 40W for first-pass PVI and no clinically significant differences in the target ablation index between the groups. When looking at all -atrial arrhythmia recurrence documented post-blanking period at 12 months, there was no statistically significant relationship (p=0.925) between groups. There was no statistically significant relationship between immediate procedural complications, pericarditis, or complications at 12 months post-ablation (p>0.05). The esophageal temperature measurements were not different between groups. HPSD is a safe and effective way of performing radiofrequency ablation of AF. HPSD using 50W was associated with shorter RF ablation and procedural times when compared to HPSD 40W without increase in complications HPSD 50W and HPSD 40W had similar acute and long-term success rates.

Gastro-Esophageal Reflux Disease and Paroxysmal Atrial Fibrillation Ablation.

The presence of typical symptoms suggestive of gastroesophageal reflux disease was clinically assessed by the gastroenterologist at baseline and at 3 months after ablation. In addition to that, all patients underwent upper gastrointestinal endoscopy. Seventy-five patients were included in two groups: 46 patients who underwent atrial fibrillation ablation (study group) and 29 patients without ablation (control group). Patients with atrial fibrillation ablation were younger (57.76 ± 7.66 years versus 67.81 ± 8.52 years; p = 0.001), predominantly male (62.2% versus 33.3%; p = 0.030) and with higher body mass index (28.96 ± 3.12 kg/m2 versus 26.81 ± 5.19 kg/m2; p = 0.046). At three months after the ablation, in the study and control groups, there were 88.9% and 57.1% patients in sinus rhythm, respectively, (p = 0.009). Symptomatic gastroesophageal reflux disease was not more frequent in the study group (42.2% versus 61.9%; p = 0.220). There was no difference in terms of sinus rhythm prevalence in patients with versus without symptomatic gastroesophageal reflux disease (89.5% versus 88.5%; p = 0.709). In this small prospective study, typical symptoms suggestive of gastroesophageal reflux disease were not more frequent three months following atrial fibrillation ablation.

Growing thrombus adhesion on the left atrial wall after catheter ablation of atrial fibrillation.

Growing thrombus adhesion on the left atrial wall after catheter ablation of atrial fibrillation.