First-pass Pulmonary Vein Isolation Research Articles

Association between left atrial wall thickness and residual potential after first-pass pulmonary vein isolation using very high-power short-duration ablation in patients with atrial fibrillation

Abstract Background In this study, we evaluated efficacy, efficiency, and safety of pulmonary vein isolation (PVI) applying vHPSD ablation strategy in patients with atrial fibrillation (AF) and explored the association between left atrial wall thickness (LAWT) and the residual potential after first-pass PVI. Methods Between April 2, 2023 and October 6, 2023, drug refractory symptomatic AF patients who underwent AF ablation using vHPSD ablation strategy with QDOT MICRO catheter were prospectively enrolled. All patients took cardiac computed tomography (CT) a day before procedure. Using CT image, LAWT map was created. PV segments were categorized into prespecified 14 segments, and LAWT of each segment, segments with residual potential (RP) after first-pass PVI and early reconnection after 20-minute waiting after PVI were evaluated. Total procedure time, ablation time for PVI, and occurrence of procedure-related complication were collected. Results A total of 40 patients were included (mean age 64 years, 45% of persistent AF). Additional ablation other than PV was performed in 48% of patients, total procedure time was 77 minutes, and total PVI time was 9.9 minutes. With vHPSD PVI, all PVs first pass isolation rate was 60%; in terms of per PV, RSPV first-pass isolation was 88%, followed by LSPV and LIPV 85%, RIPV showed lowest first-pass isolation rate, 75% (Figure A). Most common RP sites was right carina, followed by left carina (Figure A). Compared to historical comparator, vHPSD PVI showed shorter procedure time, shorter ablation time for PVI, with numerically lower but statistically comparable first-pass PVI rate (Figure B). In total 560 PV segments in 40 patients, RSPV anterior, left carina, and right carina showed higher prevalence to be thick PV segments (over 60% of patients), followed by RPSV posterior, LSPV posterior, and RIPV anterior (over 40% of patients). Looking into ablation parameter detail, mean contact force was 10g, mean temperature was 47°C, and mean impedance drop was 8.4Ω. Compared to segments without RP, segments with RP showed thicker mean left atrial wall thickness grades, lower minimum contact force, higher maximum temperature, and lower minimum impedance drop. According to the left atrial wall thickness, thick PV segments showed higher prevalence of RP after first-pass PVI with vHPSD ablation. In segments with LAWT grade 3 or more, the RP rate was 9.1%. This thickness means thicker than 1.5 to 2.0 mm of thickness (Figure C). In 10% of patients (n=4) had audible or tactile steam-pops, visible char was confirmed in 5% of patients (n=2). There were no clinical complications. Conclusion PVI using vHPSD achieved shorter procedure time, shorter ablation time for PVI, and comparable first-pass PVI rate compared to historical comparator using ablation-index guided conventional power ablation. Thick segments had higher chance to have residual potential after first-pass PVI with vHPSD.

Real-world multicenter registry on a novel focal lattice tip catheter toggling between pulsed electric field and radiofrequency for atrial tachyarrhythmia ablation

Abstract Background Pulsed field ablation (PFA) has emerged as a novel non-thermal energy source for cardiac tissue ablation. A novel focal 9mm lattice tip catheter, namely Sphere-9 (Affera Inc), has recently received regulatory approval; the technology is part of a technology that allows the delivery of either pulsed electric field or radiofrequency energy and incorporates a proprietary 3D electroanatomical mapping system. Purpose To describe the first real-world, multicenter experience with the AfferaTM system. Methods Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the AfferaTM system in two different centres between August and November 2023 were prospectively enrolled. PFA was always used to ablate the posterior left atrium, whereas anterior applications were performed using either radiofrequency energy (RF/PF strategy) or PFA (PF/PF strategy) based on operator's discretion. Data on first-pass pulmonary vein isolation (PVI) and posterior wall isolation (PWI), as well as success rate of extrapulmonary ablation were reported. Primary safety endpoint included any technology-related periprocedural complications. Results 46 patients (mean age: 67±10; 41.3% males, 60.8% non-paroxysmal AF) were included. 5 (10.8%) patients were in atrial flutter (AFlu) at the beginning of the procedure, whereas AF was the rhythm at presentation in 19 (41.3%) others. First-time PVI was performed in 37 (80.4%) patients, 68.4% of whom received concomitant PWI. PVI was performed with PFA-only in 27% of them. First-pass isolation was achieved in 97.3% and 100% of PVI and PWI cases, respectively. Additional lesions included an anterior or posterior mitral line (6 and 15 patients), CTI (4 patients) or substrate ablation in 3 patients. Evidence of first-pass line block was documented in 96.4% of patients. The remaining 9 (19.6%) patients had already undergone a previous ablation; remapping showed 27.7% of PVs requiring reisolation. PWI was performed in 88.9% of them, for the first time (75%) or due to reconnection (25%). Additional lesions included an anterior or posterior mitral line (3 and 3 patients) or CTI in 2 patients. Evidence of first-pass line block was documented in 100% of patients. In 3 AFlu patients, the arrhythmia was mapped and termination was achieved while performing an AML (2 patients) and CTI (1 patient). Procedural duration was 96.5±15.6 min for first time and 97.8±12.6 min for redo procedures. Mean left atrial dwelling and fluoroscopy times were 75.4±17.6 min and 7.36±2.1 min, respectively. No technology-related complications were documented. Conclusions AF ablation with the focal 9-mm lattice tip catheter Sphere-9 confirmed high efficacy and safety in a real-world population.

Pulsed-field ablation of atrial fibrillation in elderly and frail patients: procedural efficacy and safety from a single-center experience

Abstract Introduction The demographic data shows a growing population, mostly elderly and with multiple comorbidities, therefore becoming increasingly frail. In this context Atrial fibrillation (AF) is the predominant sustained arrhythmia, and over the years trans-catheter isolation of pulmonary veins (PVI) has become a crucial approach in AF treatment. Among the technologies and energy resources employed through the years to perform atrial fibrillation transcatheter ablation, a novel technique has recently begun to gain ground, specifically pulsed-field ablation (PFA). PFA employs sequential brief and high amplitude electrical pulses to induce selective and irreversible electroporation of the myocardium, leading to cell death. The high selectivity of the lesion, ensured by the lower electroporation threshold of myocardial tissue compared to adjacent anatomic structures, allows for a decrease in potential complications associated with conventional thermal ablation. Purpose To assess the efficacy and safety in the use of pulsed field ablation in a selected population of elderly and frail patients undergoing atrial fibrillation ablation. Method We conducted a retrospective study focusing on elderly and frail patients admitted to our centre for paroxysmal or persistent AF ablation. The inclusion criteria were: age greater than 75 years and a Clinical Frailty Scale ≥ 5. The study population consisted of 26 patients [male gender 18, mean age 78 ± 3 years] including 8 who were affected by an oncological or haematological disease at the time of admission. The majority of patients were affected by paroxysmal AF while two of them presented persistent AF (9%). The primary ablation endpoint was the pulmonary vein isolation (PVI) that was achieved by delivering an energy of 2 kV over 8 applications, employing an alternating approach between the two configurations of the basket and flower catheter for each individual vein. Results The short-term success, represented by the complete and verified electrical isolation of the veins was achieved in all 26 patients without any periprocedural complications. First-pass pulmonary vein isolation (FPI) was universally achieved among the patient in study, with a mean skin-to-skin procedural time of 70 ± 30 minutes. From the procedural data perspective, ablation was achieved using an average fluoroscopy time of 22 ± 8.4 minutes and an average dose area product (DAP) of 1320 cGy×cm2. Conclusions In elderly and frail patients, we assessed the efficacy and safety of ablative procedures using the PFA technique. Successful electrical PVI was achieved without additional touch-ups, thanks to a high FPI rate. This results in lower procedural times and shorter intra-operative radiation exposure. These data confer an augmented value within the elderly-frail population, wherein shorter procedural times contribute to a better postoperative course, characterized by reduced bed rest and shorter intra-hospitalization periods.

Procedural characteristics, details on epicardial mapping-based lesion transmurality, and long-term success of posterior wall isolation with a pentaspline pulsed field ablation device

Abstract Background Achieving durable posterior wall isolation (PWI) with thermal-based energies is challenging, as reconnection rates have been reported to be up to 60%. Additionally, PWI can significantly increase the risk of collateral thermal damage to the esophagus. Pulsed field ablation (PFA) is a non-thermal energy source with a remarkable safety profile due to its selectivity to cardiac tissue. Additionally, PWI durability was reported to be 100% in a recent phase-3 study enrolling persistent AF patients undergoing PFA via the FarapulseTM system. Purpose To report procedural details, acute lesion transmurality, and long-term success of PWI via the FarapulseTMsystem. Methods Consecutive persistent AF patients undergoing first-time ablation with the FarapulseTM system at four different centres were prospectively enrolled. All patients received first-time pulmonary vein isolation (PVI) and PWI. PFA was performed with either a 31mm or a 35mm device and an energy output of 2.0kV. At least 2 applications per position were delivered. Primary efficacy endpoint was freedom from any atrial tachyarrhythmia >30s after a 3month blanking period. PW lesion transmurality was assessed in a subpopulation of patients with an indication for hybrid AF ablation and left atrial appendage (LAA) clipping. The procedure was performed according to the following steps: 1) endocardial PVI plus PWI via the FarapulseTM system; 2) endocardial high-density mapping with RhythmiaTM plus Intellanav OrionTM; 3) thoracoscopy-assisted epicardial high-density mapping with Intellanav OrionTM 4) left atrial appendage clipping. Results 157 persistent AF patients (mean age: 62±11years; 75.5% males) were included. First-pass PVI was achieved in 100% of patients. On average, pulsed electric field applications for PWI were 16.3±2.4. Mean procedural time was 66±17min; left atrial dwelling and fluoroscopy times were 46±12min and 14±6min, respectively. SR restoration during PWI was observed in 8 (5.1%) cases. Minor and major periprocedural complications occurred in 2.5% (groin hematoma: 4pts) and 0.6% (diplopia with negative cerebral MRI) patients, respectively. During a mean follow-up of 353±58 days, arrhythmia-free survival was 78.3% (n=123). A redo ablation was performed in 23 patients, showing reconnection of 22.8% of PVs. Durable PWI was observed in 82.6% of patients. In the subpopulation of patients (n=3) undergoing hybrid ablation plus LAA clipping, thoracoscopy-guided epicardial mapping of the PW was performed between 57 and 72 minutes after the last endocardial PFA application. All patients showed transmural PWI (Figure1). Conclusions In a real-world multicenter registry, PWI by means of the FarapulseTM system was safe and feasible, contributing to approximately 80% success rate after 1 year. Endocardial PFA-based PWI led to 100% transmural lesions acutely, with a rate of reconnection <20% at redo procedures.

First clinical experience using a novel 8-spline ultra high-resolution mapping catheter to guide atrial fibrillation ablation

Abstract Background Multielectrode mapping catheters improve the detection of scarred and fibrotic tissue in patients with atrial fibrillation (AF) Recently, a novel multispline mapping catheter with 48 closely spaced microelectrodes has been introduced enabling fast high-resolution electroanatomical mapping. Objective This study sought to report our initial clinical experience with the novel Octaray catheter in patients with AF undergoing index ablation and to compare its impact on mapping and ablation with the 5-spline Pentaray catheter. Methods The study included consecutive patients who underwent index AF ablation using a multipolar mapping catheter and very high-power-short-duration guided ablation (Q4U-AF workflow; QDot; Qmode+; Biosense Webster) in conjunction with a visualized sheath (Vizigo; Biosense Webster). Arrhythmia recurrence was defined as any atrial fibrillation (AF)/ atrial tachycardia (AT) episode lasting > 30 s after a blanking period of 3 months. Results A total number of 183 patients undergoing AF ablation using the Octaray and QDot catheter were compared to a group of 166 matched patients who underwent ablation using Pentary and QDot. Utilization of the Octaray catheter resulted in an increased identification of areas with bipolar low-voltage representing fibrosis/scar or atrial cardiomyopathy (mean amount of left atrial bipolar low-voltage: Octaray 31% vs. Pentaray 18%; p= 0.03) and a higher rate of first-pass isolation (FPI) for the left-sided pulmonary veins (Octaray: FPI rate 73% vs. FPI rate 64% for Pentaray). A significantly higher number of mapping points was acquired using the novel 8-spline mapping catheter (right atrium: Octaray 1936 points vs. Pentaray 903 points; p < 0.001 left atrium: Octaray 5337 points vs. Pentaray 2385 points; p < 0.001). Procedural parameter, radiation time/dosage and acute procedural success were comparable between the two groups. During a mean follow-up of 12 months, the overall procedural success was 86 in the Octaray group vs. 84% in the control group (p=0.9). Conclusion The utilization of the novel Octaray mapping catheter resulted in an improved detection of atrial fibrosis and scar as well as a higher rate of first-pass pulmonary vein isolation. Figure: Institutional Q4U-AF-workflow using a multipolar mapping catheter, the QDot ablation catheter and a visualized sheath. High resolution mapping using the Octaray (A+B) and PentaRay catheter (C+D).

Optimization of high-power short-duration pulmonary vein isolation using QDOT catheter - the A-Q-RATE POWER trial

Abstract Background/Introduction The safety and efficacy of novel ablation catheter QDOT Micro, capable of delivering high-power short-duration (HPSD) radio-frequency (RF) applications, has already been demonstrated in clinical trials. It has been shown that lesions performed with 90 Watts/4 sec (vHPSD) are shallower but wider compared to HPSD (50 Watts/4 sec) or conventional ablation settings. Thus, it may be speculated that vHPSD applications may not achieve transmurality at thick (up to 4 mm) parts of anterior aspects of pulmonary vein (PV) - left atrial (LA) wall junction. Purpose To compare acute completeness of PV isolation (PVI) focused on anterior wall achieved using vHSPD versus HPSD in patients undergoing ablation for atrial fibrillation (AF). Methods Prospective, dual-center, randomized study was conducted over a 8-month period. Patients were randomized 1:1 to vHPSD versus HPSD delivered at anterior aspects of PV. Posterior parts of PV were ablated with vHPSD in both arms. The carina region between ipsilateral PVs was ablated using 35 W and ablation index of 380. Need for additional RF applications to achieve complete PVI was the primary outcome. Results 70 patients (mean age 63.5±11.2; 57.1% male) with paroxysmal (61.4%) or persistent AF (38.6%) were randomized to vHPSD (n=35) or HPSD (n=35). Additional RF touch-up applications at the anterior aspects of PV were significantly more frequently needed in the vHPSD group compared with the HPSD group (46% vs 19%, p<0.001) and in the right PVs (57% vs 20%, p=0.001) versus left PVs (34% vs 17%, p=0.1). Median procedure duration, LA dwell time and fluoroscopy time were similar in both groups [112 (IQR 90, 130) min vs 107 (IQR 90,125) min, p= 0.58; 95 (IQR 70,106) min vs 90 (IQR 71,100) min, p=0.55; and 28 (IQR 14,69) sec vs 46 (IQR 0,89) sec, p=0.97, respectively). In one patient in vHPSD we were not able to isolate right superior pulmonary vein (RSPV) despite additional RF touch-up applications. Conclusions vHPSD RF applications using the QDOT Micro catheter may not achieve transmurality in a significant proportion of anterior parts of PV. The proposed hybrid strategy consisting of HPSD delivery at anterior aspects of PV with vHPSD delivered at other parts of PV ostia is associated with significantly higher rate of first-pass PVI without extending procedural and fluoroscopy duration.

Identification of epicardial connections can improve the success rate of first-pass right pulmonary vein isolation

BackgroundEpicardial connections between the right pulmonary vein (PV) and the right atrium have been reported. ObjectiveWe evaluated the usefulness of our new PV isolation (PVI) strategy with identification of these epicardial connections. MethodsOverall, 235 patients with atrial fibrillation were included. High-density mapping of the left atrium was performed to identify the earliest activation sites (EASs) before PVI in all patients. With our new strategy, if we identified EASs around the right PV carina, we ablated these sites in addition to performing usual first-pass circumferential PVI. The patients were divided into two groups according to the ablation strategy. One hundred fifteen patients underwent first-pass PVI without information on EASs (non-analyzed group), and 78 patients underwent ablation at EASs around the right PV carina in addition to PVI (analyzed group). After first-pass ablation around the PV antrum, re-mapping was performed. ResultsHigh-density mapping before PVI showed that the prevalence of EASs around the right PV carina was 10.9% in all patients (9.6% in the non-analyzed group and 12.8% in the analyzed group; p = 0.74. The first-pass right PVI success rate was higher in the analyzed group than in the non-analyzed group (93.6% vs. 82.6%; p = 0.04). The radiofrequency application time for PVI was significantly shorter in the analyzed group than in the non-analyzed group (45.6 ± 1.0 min vs. 51.2 ± 0.9 min; p < 0.05). ConclusionIdentification of epicardial connections before ablation could improve the success rate of first-pass right PVI.

Where is the gap after a 90 W/4 s very-high-power short-duration ablation of atrial fibrillation?: Association with the left atrial-pulmonary vein voltage and wall thickness.

Although pulmonary vein isolation (PVI) for atrial fibrillation (AF) utilizing radiofrequency (RF) applications with a very high-power and short-duration (vHPSD) has shortened the procedure time, the determinants of pulmonary vein (PV) gaps in the first-pass PVI and acute PV reconnections are unclear. An extensive encircling PVI was performed with the QDOT MICRO catheter with a vHPSD (90 W-4 s) in 30 patients with AF (19 men, 64 ± 10 years). The association of the PV gap sites (first-pass PVI failure, acute PV reconnections [spontaneous reconnections or dormant conduction provoked by adenosine triphosphate] or both) with the left atrial (LA) wall thickness and LA bipolar voltage on the PVI line and ablation-related parameters were assessed. PV gaps were observed in 29 (6%) of 480 segments (16 segments per patient) in 17 patients (56%). The PV gaps were associated with the LA wall thickness, bipolar voltage, and the number of RF points (LA wall thickness, 2.5 ± 0.5 vs. 1.9 ± 0.4 mm, p < .001; bipolar voltage, 2.59 ± 1.62 vs. 1.34 ± 1.14 mV, p < .001; RF points, 6 ± 2 vs. 4 ± 2, p = .008) but were not with the other ablation-related parameters. Receiver operating characteristic curves yielded that an LA wall thickness ≥2.3 mm and bipolar voltage ≥2.40 mV were determinants of PV gaps with an area under the curve of 0.82 and 0.73, respectively. The LA voltage and wall thickness on the PV-encircling ablation line were highly associated with PV gaps using the 90 W/4 s-vHPSD ablation.

Index-Guided High-Power Radiofrequency Catheter Ablation for Atrial Fibrillation: A Systematic Review and Meta-Analysis Study.

Studies have suggested the superiority of high-power compared to standard-power radiofrequency ablation ablation (RFCA). This study aimed to assess the efficacy and safety of high-power compared to standard-power RFCA guided by ablation index (AI) or lesion index (LSI). A systematic review and meta-analysis study comparing IGHP and IGLP approaches for AF ablation was conducted. The relevant published studies comparing IGHP and IGSP methods for RFCA in AF patients until October 2022 were collected from Cochrane, ProQuest, PubMed, and ScienceDirect. A total of 2579 AF patients from 11 studies were included, 1682 received IGHP RFCA, and 897 received IGSP RFCA. To achieve successful pulmonary vein isolation (PVI), the IGHP RFCA group had a significantly shorter procedure time than the IGHP RFCA group (mean difference (MD) -19.91 min; 95% CI -25.23 to -14.59 min; p < 0.01), radiofrequency (RF) application time (MD -10.92 min; 95% CI -14.70 to -7.13 min; p < 0.01), and fewer number of lesions (MD -10.90; 95% CI -18.77 to -3.02; p < 0.01) than the IGSP RFCA. First-pass PVI was significantly greater in the IGHP RFCA group than in the IGSP RFCA group (risk ratio (RR) 1.17; 95% CI 1.07 to 1.28; p < 0.01). The IGHP RFCA is an effective and efficient strategy for AF ablation. The superiority of IGHP RFCA includes the shorter procedure time, shorter RF application time, fewer number of lesions for complete PVI, and more excellent first-pass PVI.

50-W vs 40-W During High-Power Short-Duration Ablation for Paroxysmal Atrial Fibrillation: A Multicenter Prospective Study

BackgroundHigh-power short-duration (HPSD) radiofrequency ablation of atrial fibrillation (AF) increases first-pass pulmonary vein isolation (PVI) and freedom from atrial arrhythmias while decreasing procedural time. However, the optimal power setting in terms of safety and efficacy has not been determined. ObjectivesThis study compared the procedural characteristics and clinical outcomes of 50-W vs 40-W during HPSD ablation of paroxysmal AF. MethodsPatients from the REAL-AF prospective multicenter registry (Real-World Experience of Catheter Ablation for Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation) undergoing HPSD ablation of paroxysmal AF, either using 50-W or 40-W, were included. The primary efficacy outcome was freedom from all-atrial arrhythmias. The primary safety outcome was the occurrence of any procedural complication at 12 months. Secondary outcomes included procedural characteristics, AF-related symptoms, and the occurrence of transient ischemic attack or stroke at 12 months. ResultsA total of 383 patients were included. Freedom from all-atrial arrhythmias at 12 months was 80.7% in the 50-W group and 77.3% in the 40-W group (Log-rank P = 0.387). The primary safety outcome occurred in 3.7% of patients in the 50-W group vs 2.8% in the 40-W group (P = 0.646). The 50-W group had a higher rate of first-pass PVI (82.3% vs 76.2%; P = 0.040) as well as shorter procedural (67 minutes [IQR: 54-87.5 minutes] vs 93 minutes [IQR: 80.5-111 minutes]; P < 0.001) and radiofrequency ablation times (15 minutes [IQR: 11.4-20 minutes] vs 27 minutes [IQR: 21.5-34.6 minutes]; P < 0.001) than the 40-W group. ConclusionsThere was no significant difference in freedom from all-atrial arrhythmias or procedural safety outcomes between 50-W and 40-W during HPSD ablation of paroxysmal AF. The use of 50-W was associated with a higher rate of first-pass PVI as well as shorter procedural times.

Optimized workflow for pulmonary vein isolation using 90-W radiofrequency applications: a comparative study.

Ninety-watt applications are more sensitive to catheter instability and produce lesions that are shallower and smaller in diameter than 50-W applications. These characteristics were considered for the development of a combined (90-50 W) pulmonary vein isolation (PVI) strategy which was prospectively compared to a 50 W-only ablation index (AI)-guided PVI strategy. One hundred fifty consecutive paroxysmal AF patients underwent PVI under general anesthesia using CARTO. In the first 75 patients, PVI was performed with a combined (90-50 W) strategy using the QDOT-MICRO catheter in a temperature-controlled mode. This strategy consisted of 90 W-4s applications on the posterior LA wall (at sites of catheter stability and expectedly thin atrial tissue) with an interlesion distance (ILD) ≤ 4mm and 50-W applications elsewhere (at sites of catheter instability or expectedly thick atrial tissue) with ILD < 6mm. In the subsequent 75 patients, PVI was performed with a 50 W-only AI-guided strategy using the SmartTouch-SF catheter in a power-controlled mode. Both groups of patients had similar clinical characteristics and LA dimensions (123.1 ± 24.9ml vs 119 ± 26.8ml, P = 0.33). Total procedural times (61 [56-70] vs 65 [60-75] min, P = 0.12), first-pass PVI (82.6 vs 80%, P = 0.81), acute PV reconnection (0 vs 6.6%, P = 0.05), and 1-year SR maintenance (93.3 vs 90.6%, P = 0.57) rates were also similar in both groups of patients. There were no complications in the combined (90-50 W) group while only 2 groin hematomas were reported in the 50 W group. In paroxysmal AF patients, a combined (90-50 W) strategy for PVI did not improve safety, efficiency, or effectiveness compared to a 50 W-only AI-guided strategy.

High-Power Short-Duration Lesion Index-Guided Posterior Wall Isolation beyond Pulmonary Vein Isolation for Persistent Atrial Fibrillation.

Background: High-power short-duration (HPSD) radiofrequency (RF) ablation has been adopted to improve atrial fibrillation (AF) ablation. Although the role of HPSD is well-established in pulmonary vein isolation (PVI), fewer data have assessed the impact of HPSD when addressing extra-pulmonary veins (PVs) targets. Therefore, this study aims to determine the safety, effectiveness, and acute outcomes of HPSD lesion index (LSI)-guided posterior wall isolation (PWI) in addition to PVI as an initial strategy in persistent atrial fibrillation (Pe-AF). Methods: Consecutive patients who underwent ablation of Pe-AF in our center between August 2021 and January 2022 were retrospectively enrolled. All patients' ablation strategy was PVI plus PWI using HPSD LSI-guided isolation. RF parameters included 50 W targeting LSI values of ≥5 on the anterior part of the PVs and anterior roofline and ≥4 for the posterior PVs aspect, bottom line, and within the posterior wall (PW). We compared the LSI values with and without acute conduction gaps after the initial first-pass PWI. Left atrial mapping was performed with the EnSite X mapping system and a high-density multipolar Grid-shaped mapping catheter. We compared the procedural characteristics using HPSD (n = 35) vs. a control group (n = 46). Results: Thirty-five consecutive patients were included in the study. PWI on top of PVI was achieved in all cases in the HPSD group. First-pass PVI was achieved in 93.3% of PVs (n = 126/135). First-pass roofline block was obtained in most patients (n = 31, 88.5%), while first-pass block of the bottom line was only achieved in 51.4% (n = 18). There were no significant differences compared to the control group; first-pass PVI was achieved in 94.9% of PVs (n = 169/178), first-pass roofline block in 89.1%, and bottom-line in 45.6% of patients. To achieve complete PWI with HPSD, scattered RF applications within the PW were necessary. No electrical reconnection of the PW was found after adenosine administration and the waiting period. The procedure and RF times were significantly shorter in the HPSD group compared to the control group, with values of 116.2 ± 10.9 vs. 144.5 ± 11.3 min, and 19.8 ± 3.6 vs. 26.3 ± 6.4 min, respectively, p < 0.001. Fluoroscopy time was comparable between both groups. No procedural complications were observed. At the 12-month follow-up, 71.4% of patients remained free from AF, with no differences between the groups. Conclusions: HPSD LSI-guided PWI on top of PVI seems effective and safe. Compared to a control group, HPSD is associated with similar rates of first-pass PWI and PVI but with a shorter procedural and RF time.

Local impedance drop guided versus lesion size index guided pulmonary vein isolation: acute success and reconnections

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Insufficient lesion depth and discontinuity of lesion lines are reasons for reconnections after point-by-point radiofrequency pulmonary vein isolation (PVI). Different technologies have shown to be useful for prediction of effective lesions. Measurement of the magnitude of local tissue impedance drop (LID) and calculation of lesion size index (LSI) based on monitoring of contact force are examples for corresponding technologies. Purpose To compare the acute efficacy of LID guided with LSI guided PVI. Methods In this retrospective study we compared two groups of patients who underwent point-by-point radiofrequency PVI for treatment of atrial fibrillation. In the LID-guided group (n=35) energy was delivered using IntellaNav MiFi (Boston Scientific, MA, USA) ablation catheter. Ablation was terminated when LID reached a plateau (Figure A). In the LSI-guided group (n=31) lesions were created using Tacticath (Abbott, MA, USA) ablation catheter until the target LSI was reached in each point (LSI=5 for anterior and LSI=4 for posterior segments respectively, Figure B). The inter-lesion distance of &amp;lt;6 mm with power of 40 W for anterior and 30W for posterior segments was used in both groups. A gap-map and touch-up ablation was performed along the index ablation line if the first pass PVI did not occur, or in the case of an acute reconnection after 20 min of waiting time. In the post hoc analysis initial levels and drop of local and system impedance, average contact force and LSI were included in models predicting PV gaps. Results All PVs were successfully isolated by encirclement of ipsilateral veins with significantly longer median ablation time 30(IQR:27-35) min in LID-guided group as compared to LSI-guided group:25 (IQR:21-31) min (p=0.035). First-pass PVI was achieved in 97 out of 132(73%) circles (LID-guided:43 out of 70 [61%] circles vs LSI-guided:54 out of 62 [87%] circles, p=0.002). Acute reconnections occurred in 14 out of 132 (11%) circles (LID-guided:9 out of 70 [13%] circles vs LSI-guided: 5 out of 62 [8%] circles, p=0.54, Figure C). Overall, significantly more patients had PV gaps when LID-guided ablation was used as compared to LSI-guided (26 out of 35[74%] vs 13 out of 31[42%] respectively, p=0.016). In the post hoc analysis a LID&amp;lt;9.7Ω was the only predictive parameter for PV gap (sensitivity=96.4%, specificity=67%). Conclusions LSI-guided ablation resulted in successful PVI with significantly shorter ablation time and fewer PV gaps as compared to LID-guided. This reflects the nature of contact force guided ablation anticipating the quality of catheter-tissue interface before each application, which is not possible with an impedance-only guided approach.

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.

PO-02-067 PREDICTORS AND IMPACT OF PULMONARY VEIN NON-RECONNECTION IN THE SECOND PROCEDURE AFTER ABLATION INDEX-GUIDED PULMONARY VEIN ISOLATION FOR ATRIAL FIBRILLATION

Reconnection of the pulmonary vein (PV) is the primary mechanism of atrial tachyarrhythmia (AT) recurrence after atrial fibrillation (AF) ablation. In patients with AT recurrence after the first ablation index (AI)-guided AF ablation, we examined the predictors of PV non-reconnection and its impact on the outcome after the second procedure. We aimed to elucidate the predictor of PV non-reconnection and its impact on the outcome after the second ablation procedure. Among the consecutive 2089 patients undergoing the first AI-guided AF ablation, we studied 289 with AT recurrence undergoing the second procedure. We compared clinical characteristics and outcomes between the patient groups with and without PV reconnection at the beginning of the second procedure. Of the 289 patients, 134 (46%) had non-reconnection, while the other 155 (54%) had reconnection at least in one PV. Patients' characteristics, including AF type (paroxysmal AF, 41% versus 48%; persistent AF, 28% versus 26%; long-standing persistent AF, 31% versus 26%, respectively, P=0.50), were similar between the two groups. The percentage of first-pass PV isolation (FPI) in both PV sides in the first ablation procedure was significantly higher in PV non-reconnection than in those with reconnection group (77% versus 43%, respectively, p<0.001). Multivariate logistic regression analysis revealed that FPI at the first procedure (odds ratio, 0.23 (95% confidence interval (CI), 0.13-0.38), p<0.001) was the only independent predictor of PV reconnection. After the second procedure, Kaplan-Meier analysis revealed that AT recurrence rate was significantly higher in patients with PV non-reconnection than in those with reconnection (Log-rank test, p=0.005). Multivariate Cox proportional hazard model analysis revealed that PV non-reconnection (hazard ratio (HR), 1.71 (95%CI, 1.14-2.55), p=0.008), left atrial dimension (1.04 (1.01-1.07), p=0.006), and left ventricular ejection fraction (0.98 (0.96-0.99), p=0.005) were independent predictors of AT recurrence. However, AF type was not: HR to paroxysmal AF (reference) was 1.10 (95%CI, 0.67-1.83) (p=0.70) in persistent AF and 1.30 (0.82-2.03) (p=0.26) in long-standing persistent AF. FPI in the first procedure was the only independent predictor of PV non-reconnection. After the second procedure, PV non-reconnection was an independent worsening predictor of AT recurrence, suggesting a need for an aggressive search for non-PV mechanisms.

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.

Clinical outcome of lesion size index-guided high-power radiofrequency catheter ablation for pulmonary vein isolation in patients with atrial fibrillation: 2-year follow-up.

The long-term efficacy of high-power (50 W) ablation guided by lesion size index (LSI-guided HP) for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) remains undetermined. Our study sought to assess the clinical efficacy of LSI-guided HP ablation for PVI in patients with AF and explore the potential predictors associated with clinical outcomes. We consecutively included 186 patients with AF who underwent LSI-guided HP (50 W) ablation at Fuwai Hospital from June 2019 to October 2021. The target LSI values of 4.5-5.5 and 4.0-4.5 at the anterior and posterior walls, respectively, were used in our study. The baseline clinical characteristics, procedural and ablation data, and clinical outcomes were evaluated. The independent potential predictors associated with AF recurrence were further evaluated. The incidence rate of first-pass PVI was 83.9% (156/186). A total of 11 883 lesions were analyzed, and compared with posterior walls of pulmonary veins, anterior walls had significantly lower mean contact force (8.2 ± 3.0 vs. 8.3 ± 2.3 g, p = .015), longer mean radiofrequency duration (16.9 ± 7.2 vs. 12.9 ± 4.5 s, p < .001) and higher mean LSI (4.8 ± 0.2 vs. 4.4 ± 0.2, p < .001). The overall incidence of periprocedural complications was 3.7%, and steam pops without pericardial effusion occurred in three patients (1.6%). During a mean follow-up of 24.0 ± 8.4 months, the overall AF recurrence-free survival was 87.1% after a single procedure. Patients with paroxysmal AF had a higher incidence of freedom from AF recurrence than those with persistent AF (91.2% vs. 80.8%, log-rank p = .034). Higher LSI (HR 0.50, p < .001) and paroxysmal AF (HR 0.39, p = .029) were significantly associated with decreased AF recurrence. By receiver operating characteristic analysis, the LSI of 4.7 and 4.3 for the anterior and posterior walls of the PVs had the highest predictive value for AF recurrence, respectively. LSI-guided HP (50 W) ablation for PVI was an efficient and safe strategy and led to favorable single-procedure 2-year AF recurrence-free survival in patients with AF. Higher LSI and paroxysmal AF were independent predictors of decreased 2-year AF recurrence. The LSI of 4.7 for the anterior wall and 4.3 for the posterior wall of the PVs were the best cutoff values for predicting AF recurrence after LSI-guided HP ablation.

Safety and Efficacy of a Novel Approach to Pulmonary Vein Isolation Using Prolonged Apneic Oxygenation

BackgroundImproved ablation catheter–tissue contact results in more effective ablation lesions. Respiratory motion causes catheter instability, which impacts durable pulmonary vein isolation (PVI). ObjectivesThis study sought to evaluate the safety and efficacy of a novel ablation strategy involving prolonged periods of apneic oxygenation during PVI. MethodsWe conducted a multicenter, prospective controlled study of 128 patients (mean age 63 ± 11 years; 37% women) with paroxysmal atrial fibrillation undergoing PVI. Patients underwent PVI under general anesthesia using serial 4-minute runs of apneic oxygenation (apnea group; n = 64) or using standard ventilation settings (control group; n = 64). Procedural data, arterial blood gas samples, catheter position coordinates, and ablation lesion characteristics were collected. ResultsBaseline characteristics between the 2 groups were similar. Catheter stability was significantly improved in the apnea group, as reflected by a decreased mean catheter displacement (1.55 ± 0.97 mm vs 2.25 ± 1.13 mm; P < 0.001) and contact force SD (4.9 ± 1.1 g vs 5.2 ± 1.5 g; P = 0.046). The percentage of lesions with a mean catheter displacement >2 mm was significantly lower in the apnea group (22% vs 44%; P < 0.001). Compared with the control group, the total ablation time to achieve PVI was reduced in the apnea group (18.8 ± 6.9 minutes vs 23.4 ± 7.8 minutes; P = 0.001). There were similar rates of first-pass PVI, acute PV reconnections and dormant PV reconnections between the two groups. ConclusionsA novel strategy of performing complete PVI during apneic oxygenation results in improved catheter stability and decreased ablation times without adverse events. (Radiofrequency Ablation of Atrial Fibrillation Under Apnea; NCT04170894)

Study on efficacy, recurrence rate and related risk factors between ablation index and contact force guided radiofrequency ablation of paroxysmal atrial fibrillation in elderly patients

Objective: To compare the efficacy, safety and recurrence rate between ablation index (AI) and contact force (CF) guided radiofrequency ablation of paroxysmal atrial fibrillation in elderly patients. Methods: Elderly patients (age ≥60 years) with paroxysmal atrial fibrillation who received radiofrequency ablation for the first time at Department of Cardiology, Beijing Friendship Hospital from April 2018 to April 2019 were enrolled. Patients were divided into 2 groups: AI-group (n=40) and CF group (n=37) depending on their ablation methods. Follow-up was performed until 1 year post the procedure, and efficacy related indexes like first-pass pulmonary vein isolation (PVI) rate, ablation duration, operation duration and major complications were compared between 2 groups. The recurrence rates between 2 groups and related risk factors after radiofrequency ablation were analyzed. Results: A total of 77 patients [mean age (68.5±6.4) years, 40 were male] were enrolled at last. In AI guided patients, frequency of first-pass PVI rate was higher [52.5%(21 cases) vs 29.7%(3 cases), P=0.011] with a shorter ablation duration [(24.5±1.7) min vs (33.7±2.2) min, P<0.001] and operation duration [(136.6±6.1) min vs (139.7±7.4) min, P=0.048] compared with CF guided group. At 1 year follow-up, AI group showed an amendatory recurrence rate in Kaplan-Meier analysis (22.5% vs 40.5%,log-rank P=0.048). Multivariate Cox regression analysis showed that CF guided ablation (HR=3.272,95%CI:1.319-8.114,P=0.011), enlarged anteroposterior diameter of the left atrium (HR=4.233,95%CI:1.511-11.862,P=0.006) and complicated with coronary heart disease (HR=4.829,95%CI:1.399-16.666,P=0.013) were independent risk factors for recurrence of atrial fibrillation in elderly patients. Conclusions: Compared with CF guided ablation, radiofrequency ablation of paroxysmal atrial fibrillation in elderly patients guided by AI showed a higher first-pass PVI rate, shorter procedure duration of both ablation time and total operation time, meanwhile a lower recurrence rate. Further analysis revealed that different ablation alternation (AI or CF), enlarged anteroposterior diameter of left atrium, and complicated with coronary heart disease are independent risk factors for recurrence after radiofrequency ablation of atrial fibrillation in elderly patients.

Effectiveness and Safety of High-Power Radiofrequency Ablation Guided by Ablation Index for the Treatment of Atrial Fibrillation.

Background To investigate the efficacy and safety of ablation index- (AI-) guided high-power radiofrequency ablation in the treatment of atrial fibrillation (AF). Methods Outcomes of radiofrequency (RF) applications were compared in a swine ventricular endocardial model (n = 10 each for 50 W, 40 W, and 30 W; AI = 500). And a total of 100 consecutive patients with paroxysmal AF undergoing pulmonary vein isolation (PVI) were included. The patients were divided into two groups (n = 50 for each) as follows: control group, treated with conventional power (30 W) ablation mode; and study group, treated with high power (40 W) radiofrequency ablation mode. All groups were treated with the same AI value guided the ablation (target AI = 400/500 on posterior/anterior wall, respectively). Acute pulmonary vein (PV) reconnection was assessed post adenosine administration 20 minutes after ablation. Subsequently, pathological observation of porcine heart lesions and necrotic tissue was performed. Additionally, statistical analyses were carried out on patients' baseline clinical characteristics, surgical data, and total RF energy. Results In swine ventricular endocardial RF applications, compared with 40 W and 30 W, the use of 50 W was associated with shallower tissue lesion depth (p < 0.001) and greater lesion maximum diameter (p < 0.001). Compared with 40 W and 30 W, tissue necrosis caused by 50 W was the deepest and largest (p < 0.001). In pulmonary vein isolation (PVI), there was no significant difference in baseline data between the study group and control group (p > 0.05). In patients with paroxysmal atrial fibrillation, the procedure time in the high-power group was significantly shortened (p < 0.001). The ablation time was significantly shorter (p < 0.001). Compared with control group, RF energy per point and acute pulmonary vein (PV) reconnection were lower (p < 0.001), and first-pass PVI was higher (p < 0.01) in study group. There were no significant differences in complications and sinus rhythm maintenance at 12 months between the two groups (p > 0.05). Conclusions Compared with conventional (30 W) PVI, AI-guided high-power (40 W) was safe and associated with shorter procedure time and reduced acute PV reconnection.