Antral Pulmonary Vein Isolation Research Articles

Anti- and pro-fibrillatory effects of pulmonary vein isolation gaps in human atrial fibrillation digital twins

Although pulmonary vein isolation (PVI) gaps and extrapulmonary vein triggers contribute to recurrence after atrial fibrillation (AF) ablation, their precise mechanisms remain unproven. Our study assessed the impact of PVI gaps on rhythm outcomes using a human AF digital twin. We included 50 patients (76.0% with persistent AF) who underwent catheter ablation with a realistic AF digital twin by integrating computed tomography and electroanatomical mapping. We evaluated the final rhythm status, including AF and atrial tachycardia (AT), across 600 AF episodes, considering factors including PVI level, PVI gap number, and pacing locations. Our findings revealed that antral PVI had a significantly lower ratio of AF at the final rhythm (28% vs. 56%, p = 0.002) than ostial PVI. Increasing PVI gap numbers correlated with an increased ratio of AF at the final rhythm (p < 0.001). Extra-PV induction yielded a higher ratio of AF at the final rhythm than internal PV induction (77.5% vs. 59.0%, p < 0.001). In conclusion, our human AF digital twin model helped assess AF maintenance mechanisms. Clinical trial registration: https://www.clinicaltrials.gov; Unique identifier: NCT02138695.

Abstract 14702: Roles of Atrial Mass Reduction and Gaps on the Anti-Atrial Fibrillatory Effects of Pulmonary Vein Isolation: A Computational Modeling Study

Background: Although pulmonary vein isolation (PVI) is the basis of atrial fibrillation (AF) catheter ablation (AFCA), the conditional changes of an anti-AF effect and the wave-dynamic mechanism are poorly understood. Therefore, we compared the effects of PVI based on the ablation circumference, width, and number or locations of gaps with or without amiodarone at the same condition in realistic computational modeling of human AF. Hypothesis: An anatomical level of PVI and characteristics of the PVI gap would affect the anti-AF effects of the AFCA. Methods: We included 50 patients (76.0% persistent AF) who underwent AFCA. Realistic AF modeling reflecting the computed tomography (CT) and the electroanatomical map was performed on each patient. We compared the AF defragmentation rate (DeFR; change to atrial tachycardia (AT) or termination), termination rate (TnR), and changes in the dominant frequency (DF) and the number of phase singularities (PSs) based on the PVI level (antral vs. ostial), PVI width (single vs. 3х width), number and location of 2-mm PVI gaps with or without amiodarone (10mM). We randomly assigned the number and location of the PVI gaps to the AF models. Results: The antral PVI had a significantly higher DeFR (p for trend &lt;0.001) and TnR (p for trend &lt;0.001) than the ostial PVI, PVI gaps, or baseline AF. However, there was no difference depending on PVI width. Among the PVI gaps, the DeFR (p for trend&lt;0.001) decreased as the gap number increased. Additional amiodarone increased DeFR (p=0.003) and TnR (p=0.034) and reduced DF (p&lt;0.001) and the number of PSs (p&lt;0.001) with PVI-gap, especially with a single PVI-gap. Conclusions: In this realistic computational modeling study with integrated patients’ atrial anatomy and electrophysiology, the atrial mass reduction depending on the anatomical PVI level, number of PVI gaps, and additional antiarrhythmic drug significantly affected the AF maintenance mechanisms.

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

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

Dynamics of left and right atrial strain after radiofrequency ablation in patients with paroxysmal and persistent atrial fibrillation

Aim. To assess the dynamics of left (LA) and right atrium (RA) strain after antral pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation.Methods. The study included 57 subjects (31 men and 26 women) aged of 55.4±9.8 years. Patients were divided into 2 groups: group 1 with paroxysmal atrial fibrillation (n=40; 70%) and group 2 with persistent atrial fibrillation (n=17; 30%). All patients were treated (were undergone) with antral isolation of the pulmonary veins. Speckle-tracking echocardiography at sinus rhythm was performed before interventional treatment, after 3 days, 3 months and one year. The reservoir, conduit and contractile LA function and peak longitudinal RA strain were analyzed.Results. In both groups, reservoir (p&lt;0.001), conductive (p&lt;0.001) and contractile LA functions (p&lt;0.001 and p=0.001) decreased significantly in the early postoperative period. LA mechanics recovered after 3 months in all patients and were comparable to the level before and one year after radiofrequency ablation. RA strain was significantly increased in the early postoperative period. RA strain was significantly higher at one year follow-up period compared with baseline.Conclusion. Catheter ablation has a damaging effect on the LA - inhibition of reservoir, conductive and contractile functions in the early postoperative period, while the RA strain is intensified. LA strain is recovered in 3 months after radiofrequency ablation and remains comparable with the baseline level at one year follow-up. Reservoir and conduction function of LA and longitudinal deformation of RA are better in the patients with a stable sinus rhythm for a year after ablation compared with patiens who had a tachyarrhythmia recurrence.

Efficacy of different variants of endocardial balloon cryoablation in patients with persistent atrial fibrillation

Aim. To study the effectiveness of “extended” cryoballon ablation in patients with a persistent form of atrial fibrillation (AF) and to determine the risk factors for AF recurrence after cryoablation.Methods. The study included 89 patients (62±10 years, 24 [27%] men) with a persistent form of AF. The patients were randomized into two groups: in the 1st, the pulmonary veins (PV) cryoablation was performed (n=48 [53.9%]); in the 2nd, the PV cryoablation was performed in combination with cryoablation of the posterior wall of the left atrium (n=41 [46.1%]). The number of patients at high risk of thromboembolic events predominated in Group 2 (p=0,03). There is a high frequency of taking antiarrhythmic drugs of class III in this group (p=0.018). The follow-up period was 12 months. Clinical efficacy was assessed during a survey and daily ECG monitoring at face-to-face visits after 3, 6 and 12 months.Results. Antral isolation of PV was achieved in all 89 (100%) patients in both groups. In group 2, the average number of applications in the posterior wall of the PV was 10 [9; 13]. The effectiveness of cryoablation in group 1 by the end of the 12-month follow-up period was 54.2%, in group 2 - 56.1%. The complication rate (6.7%) in both groups did not differ statistically (p=0.683). The risk of arrhythmia recurrence didn’t depend on the strategy of cryoablation in postablation period (p=0.834). When conducting a single-factor analysis, a statistically significant effect on the probability of AF recurrence in the period of 3-12 months in group 1 was caused by AF recurrence in the blind period (95% confidence interval (CI): 1.5-27.7, p=0.013), in group 2 belonging to the female sex (95% CI: 1.2-24.6, p=0.032) and AF relapse in the blind period (95% CI: 1.5-128.5, p=0.020). During multivariate analysis in group 2, a statistically significant influence on the risk of AF recurrence in the period of 3-12 months was exerted by belonging to the female sex (hazard ratio (HR) 7.84; 95% CI 1478-42,23; p=0.016) and the presence of early AF recurrence (HR 20.36; 95% CI 1.99-208.23; p=0.011).Conclusion. Extended cryoablation in terms of efficiency and safety was comparable with the standard cryoablation. Early recurrence of AF (in the first 3 months after the intervention) turned out to be an independent risk factor for AF recurrence in the long-term period up to 12 months after cryoablation in both groups.

Insights into level of pulmonary vein isolation using pulsed-field ablation for atrial fibrillation and unexpected effects in the posterior wall

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Pulse field ablation (PFA) has emerged as an effective, safe and efficient tool for pulmonary vein isolation (PVI). Purpose We studied the extent of PVI, specifically the isolation of PV antrum, carina and left atria’s posterior wall after PFA with an ultrahigh density mapping (UHD). Methods We involved the first patients referred for atrial fibrillation (AF) ablation treated with a PFA multispline catheter. PFA-lesion extension was assessed with a voltage-map UHD mapping performed before and immediately after PVI. Results Sixty-one consecutive patients underwent PVI with PFA (62±10 year old, 23 women, 39 paroxysmal AF). Four out of 61 patients were excluded because their posterior wall was isolated with extra aplications on purpose. Acute results involved a 100% success of PVI and the only safety issue was a pericardial effusion in one patient managed conservatively. Mean procedure and fluoroscopy times were 59±39 min and 16±5 min, respectively. UHD immediately after PVI revealed early reconnection just in one vein (1/228 veins). PFA created wide antral circumferential lesions without electrical activity registered by UHD mapping inside the isolation area. There were no notch-like normal voltage areas at the anterior or posterior side of carinas. As a result of the PVI with this technology, it was observed the existence of a narrow corridor in the posterior wall in 8 patients (14%) and in another 8 cases right and left antral ablation converged at the posterior wall creating an unexpected isolation area. There was a significant relationship between LA posterior inter-carina distance and posterior wall´s level of isolation (77,1±7mm, no affectation; 68,8±7mm narrow corridor; 60,3±1mm posterior wall isolation (fig 1); p=0.036). Finally, it was a significant linear correlation between posterior inter-carina distance and the distance between the ipsilateral, antral levels of isolation at the posterior wall (fig 2, r=0.79, p=0.001) Conclusion(s) PFA creates wide antral circumferential PVI lesions involving the ipsilateral veins carina. Nevertheless, in small left atria it can create an undesired isolation or a narrow corridor in the posterior wall.

Relationship between the left atrial and pulmonary vein effective refractory period and the development of early atrial fibrillation recurrence after radiofrequency pulmonary vein isolation. First results

Aim. To assess the relationship between the left atrial (LA) and pul­monary vein (PV) effective refractory period and the development of early atrial fibrillation (AF) recurrence after radiofrequency pul­monary vein isolation (PVI).Material and methods. The study included 35 patients with persistent AF refractory to antiarrhythmic therapy (AAT). In all patients, LA and PV effective refractory period (ERP) was assessed, followed by radiofrequency antral PVI. Depending on the ERP values, the patients were divided into 2 groups. Group 1 (n=15) included patients with mean LA and PV ERP values ≥240 ms, while group 2 (n=20) consisted of patients with mean LA and PV ERP values &lt;240 ms. The evaluation of early AF recurrence, depending on the obtained ERP values, was carried out in the first 3 months.Results. We obtained following ERP values: group 1 — LA (LA ap­ pendage) 252±8,9 ms; left superior PV (LSPV) — 252±12,1 ms; left inferior PV (LIPV) — 257,3±8,15 ms; right superior PV (RSPV) — 254,6±11,3 ms; right inferior PV (RIPV) — 260±9,05 ms; group 2 — LA 230±12,1 ms; LSPV — 205±10,5 ms; LIPV — 186,6±22,05 ms; RSPV — 212,2±14 ms; RIPV — 218,8±11,1 ms. During the 3-month follow-up of group 1 patients, there were no recurrences after PVI. Group 2 had 7 early AF recurrences. Correlation analysis revealed a significant inversely proportional relationship (-0,349; p=0,03) between ERP values and the recurrence rate in the groups.Conclusion. The first results demonstrate an inversely proportional relationship between the mean PV and LA ERP and the development of early AF recurrence, which makes it possible to consider the PV and LA ERP &lt;240 ms as a likely predictor of early AF recurrence. However, this fact requires the study continuation with an increase in the sample and an appropriate statistical analysis.

PO-02-094 ALL PULMONARY VEIN ISOLATION STRATEGIES ARE EQUALLY EFFECTIVE IN REDUCING THE RECURRENCE OF ATRIAL ARRHYTHMIAS

Ostial and antral pulmonary vein isolation techniques have different properties. In addition, there are differences between radiofrequency and cryoballoon ablation based on tissue contact characteristics. Finally, posterior wall isolation (PWI) has been proposed as an adjuvant to PVI because of embryological origin similarities. We examine the results of ostial and antral RF ablation, cryoballoon PVI and PWI adjunction in the DECAAF-II trial with regard to the recurrence of atrial arrhythmias after ablation. Patients with persistent AF from the DECAAF-II trial who underwent PVI only or PVI + PWI were included. All patients underwent LGE-MRI before ablation and 3 months after ablation. The electroanatomic maps at time of procedure displaying the location of ablation lesions were merged with baseline LGE-MRI images, and two reviewers analyzed and classified the resulting reconstructions. PVI were classified as ostial if the lesions were in the immediate proximity of the pulmonary veins’ ostium and as antral if the lesions included a portion of the antrum around the pulmonary veins. Patients with PVI + PWI were extracted as a separate group. Patients were followed up for a total of 18 months using daily single-lead smartphone ECG strips. The primary outcome of this analysis was recurrence of atrial arrhythmias after the 90-day blanking period. A total of 367 patients were considered for analysis. 211 patients underwent ostial PVI, 81 antral PVI, 31 had PVI + PWI, and 44 underwent cryoablation. Baseline characteristics were comparable in terms of age, sex, fibrosis percentage, comorbidity profile (hypertension, diabetes, hyperlipidemia, CAD, history of stroke), and medication history, except for a significant difference in history of heart failure (10.4% vs. 18.5% vs. 29% vs. 27.3%, p = 0.004) and prior AAD use (46.9% vs. 44.4% vs. 64.5% vs. 29.5%, p = 0.026). Recurrence rates were comparable among the four groups: 91 (43%) patients had recurrence in the ostial PVI group, 39 (48%) in the antral PVI group, 12 (39%) in the PWI group, and 22 (50%) in the cryoablation group (log rank P=0.76). In patients with persistent AF, all PVI techniques show equal efficacy in terms of atrial arrhythmia recurrence. Isolation of the posterior wall during ablation in persistent AF has no procedural advantage.

Prospective randomized comparison between upgraded ‘2C3L’ vs. PVI approach for catheter ablation of persistent atrial fibrillation: PROMPT-AF trial design

In randomized studies, the strategy of pulmonary vein antral isolation (PVI) plus linear ablation has failed to increase success rates for persistent atrial fibrillation (PeAF) ablation when compared with PVI alone. Peri-mitral reentry related atrial tachycardia due to incomplete linear block is an important cause of clinical failures of a first ablation procedure. Ethanol infusion (EI) into the vein of Marshall (EI-VOM) has been demonstrated to facilitate a durable mitral isthmus linear lesion. This trial is designed to compare arrhythmia-free survival between PVI and an ablation strategy termed upgraded '2C3L' for the ablation of PeAF. The PROMPT-AF study (clinicaltrials.gov 04497376) is a prospective, multicenter, open-label, randomized trial using a 1:1 parallel-control approach. Patients (n = 498) undergoing their first catheter ablation of PeAF will be randomized to either the upgraded '2C3L' arm or PVI arm in a 1:1 fashion. The upgraded '2C3L' technique is a fixed ablation approach consisting of EI-VOM, bilateral circumferential PVI, and 3 linear ablation lesion sets across the mitral isthmus, left atrial roof, and cavotricuspid isthmus. The follow-up duration is 12 months. The primary end point is freedom from atrial arrhythmias of >30 seconds, without antiarrhythmic drugs, in 12 months after the index ablation procedure (excluding a blanking period of 3 months). The PROMPT-AF study will evaluate the efficacy of the fixed '2C3L' approach in conjunction with EI-VOM, compared with PVI alone, in patients with PeAF undergoing de novo ablation.

Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation

Pulmonary vein isolation (PVI) alone is less effective in patients with persistent atrial fibrillation (AF) compared with paroxysmal AF. The left atrial posterior wall may contribute to maintenance of persistent AF, and posterior wall isolation (PWI) is a common PVI adjunct. However, PWI has not been subjected to randomized comparison. To compare PVI with PWI vs PVI alone in patients with persistent AF undergoing first-time catheter ablation. Investigator initiated, multicenter, randomized clinical trial involving 11 centers in 3 countries (Australia, Canada, UK). Symptomatic patients with persistent AF were randomized 1:1 to either PVI with PWI or PVI alone. Patients were enrolled July 2018-March 2021, with 1-year follow-up completed March 2022. The PVI with PWI group (n = 170) underwent wide antral pulmonary vein isolation followed by posterior wall isolation involving linear ablation at the roof and floor to achieve electrical isolation. The PVI-alone group (n = 168) underwent wide antral pulmonary vein isolation alone. Primary end point was freedom from any documented atrial arrhythmia of more than 30 seconds without antiarrhythmic medication at 12 months, after a single ablation procedure. The 23 secondary outcomes included freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures, freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures, AF burden between study groups at 12 months, procedural outcomes, and complications. Among 338 patients randomized (median age, 65.6 [IQR, 13.1] years; 76.9% men), 330 (97.6%) completed the study. After 12 months, 89 patients (52.4%) assigned to PVI with PWI were free from recurrent atrial arrhythmia without antiarrhythmic medication after a single procedure, compared with 90 (53.6%) assigned to PVI alone (between-group difference, -1.2%; hazard ratio [HR], 0.99 [95% CI, 0.73-1.36]; P = .98). Of the secondary end points, 9 showed no significant difference, including freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures (58.2% for PVI with PWI vs 60.1% for PVI alone; HR, 1.10 [95% CI, 0.79-1.55]; P = .57), freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures (68.2% vs 72%; HR, 1.20 [95% CI, 0.80-1.78]; P = .36) or AF burden (0% [IQR, 0%-2.3%] vs 0% [IQR, 0%-2.8%], P = .47). Mean procedural times (142 [SD, 69] vs 121 [SD, 57] minutes, P < .001) and ablation times (34 [SD, 21] vs 28 [SD, 12] minutes, P < .001) were significantly shorter for PVI alone. There were 6 complications for PVI with PWI and 4 for PVI alone. In patients undergoing first-time catheter ablation for persistent AF, the addition of PWI to PVI alone did not significantly improve freedom from atrial arrhythmia at 12 months compared with PVI alone. These findings do not support the empirical inclusion of PWI for ablation of persistent AF. anzctr.org.au Identifier: ACTRN12616001436460.

A macroreentrant biatrial tachycardia via the posterior interatrial connection emerged after extensive catheter ablation for paroxysmal atrial fibrillation

Recent electrophysiological studies have demonstrated the existence of an epicardial connection via posterior interatrial fibers, which connect the antrum of the right pulmonary veins and the right atrium (RA).1 This connection represents a potential mechanism for the interference of circumferential antral pulmonary vein isolation.2 The posterior interatrial connection has also been reported as a critical limb of biatrial reentrant circuits in a rare condition with interatrial septal incisions after mitral valve surgery.

Characterization of circumferential antral pulmonary vein isolation areas resulting from pulsed-field catheter ablation.

The cornerstone of pulmonary vein (PV) isolation (PVI) is a wide-area circumferential ablation (WACA) resulting in an antral PVI area. Pulsed-field ablation (PFA) is a new nonthermal 'single-shot' PVI technique resulting in well-characterized posterior isolation areas. However, information on circumferential PVI area is lacking. Thus, we sought to characterize the circumferential antral PVI areas after PFA-PVI. Atrial fibrillation (AF) patients underwent fluoroscopy-guided PVI with a pentaspline PFA catheter. Ultra-high-density voltage maps using a 20-polar circular mapping catheter were created before and immediately after PVI to identify and quantify (i) insufficient isolation areas per antral PV segment (10-segment model) and (ii) enlarged left atrial (LA) isolation areas (beyond the antral PV segments) per LA region (8-region model). The PFA-PVI with pre- (5469 ± 1822 points) and post-mapping (6809 ± 2769 points) was performed in 40 consecutive patients [age 62 ± 6 years, 25/40 (62.5%) paroxysmal AF]. Insufficient isolation areas were located most frequently in the anterior antral PV segments of the left PVs (62.5-77.5% of patients) with the largest extent (median ≥0.4 cm2) located in the same segments (segments 2/5/8). Enlarged LA isolation areas were located most frequently and most extensively on the posterior wall and roof region (89.5-100% of patients; median 1.1-2.7 cm2 per region). Fluoroscopy-guided PFA-PVI frequently results in insufficient isolation areas in the left anterior antral PV segments and enlarged LA isolation areas on the posterior wall/roof, which both may be extensive. To optimize the procedure, full integration of PFA catheter visualization into three-dimensional-mapping systems is needed.

Characterization of the circumferential cevel of the pulmonary vein isolation area using pulsed-field catheter ablation: Spatial distribution and extent of insufficient and excessive isolation areas

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The cornerstone of pulmonary vein isolation (PVI) is a wide area circumferential ablation (WACA) resulting in an isolation area encompassing the PV antrum. Pulsed field ablation (PFA) is a new non-thermal "single-shot" PVI device with promising success rates. However, the circumferential level of its PV isolation area is still unknown. Objective To characterize the circumferential acute PV isolation area by assessing the spatial distribution (qualitative analysis) and extent (quantitative analysis) of insufficient PV antral and excessive LA isolation areas. Methods In this study, patients with paroxysmal or persistent atrial fibrillation (AF) underwent PVI with a pentaspline PFA catheter. Before and immediately after PVI, ultra-high-density (UHD) voltage maps using a 20-polar circular mapping catheter were created. The insufficient isolations areas per antral PV segment (10-segment model) and excessive isolation areas per LA region (8-region model) were quantified. Results Between November – December 2021, in forty consecutive patients (age 62 ± 6 years, 28/40 [70%] male, LA 41 ± 4 mm) acute PVI using PFA was achieved and pre (5469 ± 1822 points) and post mapping (6809 ± 2769 points) was performed. The anterior antral PV segments of the left PVs were the most frequent locations of insufficient isolation areas (Table 1, Figure 1). The largest extent of insufficient isolation areas at the PV antral level was located again on the anterior parts of both left PVs (Figure 2A), but also in the anterior lower segment of the right inferior PV (Figure 2B). The posterior wall and roof region of both LA sides were the most frequent locations of excessive isolation areas (Figure 4). The extent of this excessive isolation at the roof and the posterior wall on both LA sides even resulted in a connection of the both-sided low voltage areas in 18% and 8%, respectively. Conclusion When using PFA to achieve a circumferential antral PVI, efforts should be made to enhance anterior antral PV segment and prevent excessive posterior wall and roof ablation. For further optimizing the procedure, full integration of PFA catheter visualization into 3D-mapping systems is needed.

Impact of very wide antral pulmonary vein isolation on esophageal temperature changes during pulsed field ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Esophageal thermal injury (ETI) is a serious drawback of available energy sources for atrial fibrillation (AF) ablation, especially on the posterior left atrial (LA) wall. Pulsed field ablation (PFA) is a novel non-thermal energy source with promising safety advantages over existing methods due to its unique myocardial tissue specificity sparing the esophagus. Objective To evaluate esophageal temperature changes during very wide antral pulmonary vein isolation (PVI) using the PFA system. Methods Thirteen consecutive AF patients (62% with paroxysmal AF; age: 61 years; 70% male) underwent first-time PFA under deep sedation. Eight pulse trains (2kV/2.5 sec, bipolar, biphasic, 4x basket/flower configuration each) were delivered to each pulmonary vein (PV). Extra pulse trains in the flower configuration were added for very wide antral circumferential ablation (vWACA). Continuous intraluminal esophageal temperature (TESO) was monitored with an S-shaped esophageal temperature probe. Results A median of 32 (IQR 32;32) and 8 (IQR 8;9) pulse trains for PVI and vWACA with a procedural time and catheter dwell time of 67 min (IQR 61-69) and 17 min (IQR 16-18) were applied. PFA with vWACA resulted in consecutive posterior LA wall isolation in 11/13 patients. Fluoroscopically, the esophagus coursed near the right PVs in 2/13, left PVs in 8/13 and mid-posterior wall position in 3/13 patients. Maximum TESO increase from baseline was 0.8 ±0.9 °C. However, no clinically relevant TESO changes occurred (Table 1). On short-term, all patients remained asymptomatic for sore throat, cough, or other symptoms potentially related to ETI. No esophago-duodenoscopy was necessary. Conclusion PFA of the PVs and lesion extension to the posterior LA wall demonstrated clinically non-significant TESO changes and has the potential to eliminate the risk of a thermal damage to the esophagus.

PO-695-08 PULMONARY VEIN ISOLATION (PVI) AND POSTERIOR WALL ISOLATION (PWI) FOR ATRIAL FIBRILLATION USING POINT-BY-POINT PULSED ELECTRIC FIELDS: SPACE AF ACUTE RESULTS

Pulsed electrical field (PEF) has been used for pulmonary vein isolation (PVI). The CENTAURI System enables PEF ablation via standard contact force ablation catheters. The point-by-point clinical workflow may enable treatment beyond PVI, including posterior wall isolation (PWI). SPACE AF study is evaluating feasibility and safety of PVI with PWI using PEF in patients with high burden paroxysmal and persistent AF. CENTUARI PEF System (Galaxy Medical) and a focal contact force sensing catheter (ThermoCool ST, Biosense Webster) were used for PEF ablation for wide antral PVI with PWI. Operators chose one of three doses (19A, 22A, 25A) with contact force of >5g. Primary efficacy outcome was entrance/exit block of all pulmonary veins (PVs) after a 20-minute wait. Composite safety endpoint comprised of pre-specified adverse events including microbubble formation on intracardiac echo (ICE), ST-segment changes, phrenic nerve palsy, esophageal temperature rises, NIH stroke scale (NIHSS) changes, PV stenosis, and silent cerebral lesions after PEF ablation. CT of the PVs will be done at 3 months. Cranial MRI was done at 24 hours in a subset of patients. Secondary endpoint includes recurrence of AF post-ablation at 6 and 12 months with serial Holter monitoring. SPACE AF will report on 30 patients. Thus far, 12 patients (58% Male, age 55.8±10.5 years) have been treated. Acute PVI and PWI was achieved in all 12 patients (100%). An average of 113.8±12.1 applications were delivered per patient. Energy settings were 32% at 22A and 68% at 25A. There were no ST-segment changes, microbubble formations, phrenic nerve injuries, or esophageal temperature rises during PEF ablation. There were no changes to NIHSS pre- vs. post-procedure. Three (3) patients have participated in the cranial MRI sub-study, and all had negative DWI and FLAIR post-procedure. No patients experienced procedure- or device-related AEs at 30 days. PV anatomy will be assessed at 90 days. Long-term AF recurrence outcomes will be assessed at 6-month and 12-month follow-up via 48-hour Holter. Cardiac ablation using PEF delivered through standard focal catheters is safe and acutely successful when performing PWI after PVI. Further results on additional patients and AF recurrence will be presented.

Low voltage-guided ablation of posterior wall improves 5-year arrhythmia-free survival in persistent atrial fibrillation.

The posterior wall (PW) has been proposed as a standard target for ablation beyond pulmonary vein antral isolation(PVI) in patients with persistent atrial fibrillation(AF). However, studies have shown inconsistent outcomes with the addition of PW ablation. The presence or absence of low voltage on the PW may explain these inconsistencies. We evaluated whether PW ablation based on the presence or absence of low voltage improves long-term arrhythmia-free outcomes. We retrospectively reviewed 5-year follow-up in 152 consecutive patients who received either standard ablation (SA) with PVI alone or PVI + PW ablation (PWA) based on physician discretion (n = 77) or voltage-guided ablation (VGA) with PVI and addition of PWA only if low voltage was present on the PW (n = 75). The two groups were well matched for baseline characteristics. At 5-year follow-up, 64% of patients receiving VGA were atrial tachyarrhythmia(AT)/AF free compared to 34% receiving SA (HR 0.358 p < .005). PWA had similar AF recurrence in SA and VGA groups (0.30 vs. 0.27 p = .96) but higher AT recurrence when comparing SA and VGA groups (0.39 vs. 0.15 p = .03). In multivariate analysis, both VGA and PWA predicted AF arrhythmia-free survival (HR 0.33, p = .001 and HR 0.20, p = .008, respectively). For AT, VGA predicted arrhythmia-free survival (HR 0.22, p = .028), while PWA predicted AT recurrence (HR 4.704, p = .0219). VGA of the posterior wall ablation beyond PVI in persistent AF significantly improves long-term arrhythmia-free survival when compared with non-voltage-guided ablation. PW ablation without voltage-guidance reduced AF recurrence but at the cost of a higher incidence of AT.

On a Possible Approach to Risk Prediction of Recurrence of Atrial Fibrillation аfter Catheter Ablation According to Data from the Pre-procedure Period

The aim of the study is to identify and evaluate predictors of recurrent paroxysms of atrial fibrillation (AF) paroxysms based on data from the preprocedural period among personal indices, history, comorbidities, ultrasound examination, and morphological components of f-waves, such as spectral amplitude and frequency. 39 patients with antral pulmonary vein isolation using radiofrequency or cryoenergy were included. Spectral analysis of f-waves was performed by fast Fourier transform of the ECG signal after suppression of the T-wave and QRS-complex. The performed U-test for the difference between the amplitude and frequency indicators in the groups without and with recurrence of AF shows a significant difference between the amplitude values in the two studied groups of patients. Through a stepwise discriminant analysis of a total of 14 indicators, 5 reliably separated groups without and with recurrence were determined: Echo LV-EF, spectral amplitude of f-waves, heart failure, Stroke/TIA, diabetes. The discriminator synthesized on these indicеs classified among the 39 patient – 25 without relapse (group 1) and 14 with relapse (group 2), 3 patients wrong from group 1 to group 2 (false positive), or 12%, and 1 patient was wrong from group 2 to group 1 (false negative), or 7.1%. These results give grounds to accept the hypothesis that it is possible to develop a decision rule for determining the degree of risk of post-procedural recurrence of AF from pre-procedural period data.

High power short duration (HPSD) versus lower power longer duration (LPLD) atrial fibrillation ablation: a multi-centre randomised controlled trial (HiLo-HEAT study)

Abstract Funding Acknowledgements Type of funding sources: None. Background  Lower power (25W) longer duration (LPLD) radiofrequency (RF) ablation has conventionally been used on the posterior wall during pulmonary vein isolation (PVI) for atrial fibrillation (AF), to attenuate the risk of esophageal thermal injury (ETI). High power (40-50 W) short duration (HPSD) RF ablation results in shorter procedural times with no increase in ETI. However evidence had been limited by non-randomised studies. Purpose  To compare HPSD versus LPLD ablation and the effects on esophageal thermal injury (ETI) and procedural outcomes. Methods  In this multi-centre, prospective, randomised control trial, 88 patients with paroxysmal/persistent AF undergoing their first RF ablation procedure were randomised 1:1 to HPSD or LPLD ablation. Anterior wall ablation was done in both arms using 40-50 W, with ablation target of AI 500-500/ LSI 5-5.5. Posterior wall ablation was done using 40-50W (HPSD group) versus 25 W (LPLD group), with target AI 400/ LSI 4. Ablation involves wide antral circumferential PVI using contact force sensing ablation catheters, with additional ablation lines as per operator discretion. Circa multi-sensor esophageal temperature monitoring (ETM) probe was utilized. Endoscopy was performed within 24 hours to assess for ETI. The primary outcome was incidence of ETI, with secondary outcomes including acute procedural endpoints. Results  Mean age of the cohort was 61+/-9 years, with 31% females. 36 (41%) had PAF. PVI was achieved in 100% of patients, with posterior wall isolation (PWI) added in 19 PsAF patients (21.6%). There were more hypertensive patients in HPSD (p = 0.02). Significant esophageal luminal temperature rises (≥ 38 c) were seen in 93.2% of patients, with no difference between groups (p = 0.69). First pass isolation rates for left and right PVs were 85% and 61% respectively, with similar rates in both groups (p = 0.37, p = 0.65 respectively). HPSD group had shorter RF time (1613 vs 2303 secs, p &amp;lt;0.04), and fluoroscopy times (11.4 vs 13.1 mins, p = 0.05). Procedural times were lower in HPSD, although not significant (133.7 vs 150.8 mins, p = 0.10). Post ablation endoscopy showed 4 cases of ETI (4.5%), with equal occurrence in HPSD and LPLD (p = 1.0). All ETIs were class 2a (superficial ulcer), and treated with PPI therapy. Esophageal injuries not attributable to RF ablation occurred in 9 (10%), with no difference between groups (p = 0.29). There was no difference in AF recurrence between the 2 groups (post 3 months blanking period) after a mean follow up of 6.3 months (p = 0.71). Conclusion  HPSD ablation was associated with lower RF ablation and fluoroscopy times compared to LPSD, with comparably low rates of ETI on post ablation endoscopy. Our findings suggest that HPSD ablation is a safe and efficacious approach to PVI. However clinicians should be cognisant of the potential injury risk related to esophageal instrumentation from transesophageal echo/ ETM probes.

Beyond pulmonary vein isolation for persistent atrial fibrillation: sequential high-resolution mapping to guide ablation

PurposeWe aimed to evaluate whether outcomes with ablation in persistent (PsAF) and long-standing persistent (LsPsAF) AF can be improved beyond what can be achieved with pulmonary vein isolation (PVI) alone, using individualized mapping to guide ablation.MethodsWe studied 20 pts (15 M, 68 ± 11y) with PsAF (14) or LsPsAF (6) referred for first-time AF ablation. Following antral PVI, individualized mapping (IM) was performed using a high-density mapping catheter stably and fully deployed for 30 s at each of 23 ± 9 sites per patient. Activation data were reviewed, and an ablation strategy designed to intersect areas of focal and rotational activity. Mean follow-up was 429 ± 131 days. The study population was compared to a matched contemporary control cohort (CC) of 20 consecutive patients undergoing conventional ablation.ResultsDespite the IM group having a higher median comorbidities score, 3.5 vs. 2.5 in the CC group, indicating potentially more complex patients and more advanced substrate, cumulative freedom from AF after a single procedure was achieved in 94% of patients in the IM group vs. 75% in the CC group at 1 year and remained the same in both groups at the conclusion of the study (p = 0.02). There was a similar trend in atrial arrhythmia-free survival between both groups (84% vs. 67% at 1 year) that did not reach statistical significance. The procedure duration was longer in the IM group by a median of 31.5 min (p = 0.004).ConclusionsIndividualized mapping to guide AF ablation appears to achieve significantly greater AF-free survival compared to conventional PVI when applied as a primary ablation treatment. The results of this pilot study need to be confirmed in a larger, randomized trial.

ОТДАЛЕННЫЕ РЕЗУЛЬТАТЫ МИНИИНВАЗИВНОЙ ЭПИКАРДИАЛЬНОЙ ВИДЕОАССИСТИРОВАННОЙ РАДИОЧАСТОТНОЙ ИЗОЛЯЦИИ ЛЕГОЧНЫХ ВЕН ПРИ ИЗОЛИРОВАННОЙ ФИБРИЛЛЯЦИИ ПРЕДСЕРДИЙ

Aim. To analyze long-term results of the use of minimally invasive epicardial video-assisted radiofrequency ablation (RFA) of the pulmonary veins (PV) in patients with various forms of isolated atrial fibrillation (AF). Materials and methods. Since February 2011 to December 2014, 22 patients (male/female – 21/1) with paroxysmal / persistent / long-standing persistent idiopathic form of AF were operated on the basis of the Republican Scientific and Practical Center “Cardiology”, 7 (31.8%) / 9 (41%) / 6 (27.2%) cases respectively. Mean age was 48.33 ± 9.37 (31–66) years old. The average duration of the history of AF before the operation was 58.6 ± 32.5 months. RFA was performed through a bilateral mini-thoracotomy approach using video endoscopy with the application of bipolar irrigated Gemini X ablative clamp electrodes. All patients underwent bilateral antral RFA isolation of the PVs. In 100% of patients it was possible to achieve a conduction block from the PV collectors. Results. During the hospital period, there were not no lethal cases, conversions to sternotomy, and neurological complications. The long-term period was studied in 100% of patients, the average follow-up period was 7.4+0.5 years. The final rhythm was assessed using Holter monitoring in 3, 6, and 12 months after surgery, then annually. In 6 (28%) cases in patients with initial non-paroxysmal AF, endocardial RFA of the isthmus of the right atrium or PV orifices was performed at different times after surgery due to the presence of atrial flutter (4/19%) or AF (2/9.5%). Implantation of the pacemaker was required in 2 cases (9.0%). The ef fectiveness of bipolar antral RFA isolation of the PV using the Gemini X device, depending on the initial form of AF in the long-term period: paroxysmal – 100%, persistent – 66.7%, long-term persistent – 33.3%. Conclusion. Epicardial minimally invasive bipolar antral PV isolation is a highly effective treatment for paroxysmal AF. In non-paroxysmal forms of AF, it is necessary to expand isolation of arrhythmogenic zones in the atria.