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Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is the most effective rhythm control treatment for atrial fibrillation (AF). While it was indicated as a symptomatic treatment in the past years, prognostic benefits of early rhythm control (ERC) were recently demonstrated and catheter ablation advances more and more into this indication. Restrictions in patient selection for catheter ablation seem to melt. Only few data on comorbidity burden in patients undergoing AF ablation is available. Purpose To determine prevalence of common cardiovascular and related comorbidities in patients undergoing left-atrial (LA) procedures between 2010 and 2021 at a large tertiary-care ablation center.. Method Eligible cases with LA procedures were identified through analysis of coded OPS data between 2010 and 2021. Analysis included patients with atrial fibrillation undergoing an ablation procedure including a transseptal puncture and mapping in the left atrium, not for other supraventricular tachycardias. Analysis accounted for different versions of the ICD-10-GM and OPS-ICHI catalogues. Comorbidities were defined as derived variables on a case-wise analysis from documented ICD-10 and OPS codes. CHA2DS2-VASc-score was calculated from these derived variables and demographic parameters. Procedures were clustered by intervention year in one of following ranges 2010-2012, 2013-2015, 2016-2018 and 2019-2021. Results 8396 left atrial procedures in 6184 individual patients (35% female, 63.6±11.0 years old at index procedure) were identified. Median CHA2DS2-VASc was 2 (IQR 1;3) in the overall cohort. Mean age increased constantly from 60.3±11.4 years in 2011 to 64.5±11.1 years in 2021. Median CHA2DS2-VASc-score remained constant at 2 points. While the share of non-paroxysmal AF patients was 52% between 2010 and 2012, it increased to 59% in 2016-2018 and decreased again to 55% in 2019-2021. The relative number of cases in which patients suffered from diabetes mellitus, chronic kidney disease, chronic obstructive pulmonary disease (COPD), obstructive sleep apnea (OSA), pulmonary hypertension, coronary artery disease and prior myocardial infarction increased constantly between 2010-2012. While the share of patients with heart failure was highest between 2013 and 2015 (1368/2117 cases, 65%), it decreased to 833/2318 cases (36%) in 2019-2021. the absolute number of procedures nearly doubled from 2010-2012 to 2013-2015, it increased by only 36% from range 2013-2015 to 2016-2018. The number of procedures decreased again from 2016-2018 to 2019-2021 by 19%, likely due to COVID19-pandemic restrictions. Conclusion Over the last decade, the age and number of comorbidities increased in patients undergoing AF ablation procedures. These results put emphasis on offering safe procedures and perform adequate pre-procedural assessment of comorbidity burden.

Funding Acknowledgements Type of funding sources: None. Background A novel multi-electrode radiofrequency balloon (RFB) catheter has been released for pulmonary vein isolation (PVI). Objectives First multicenter real-world study to evaluate predictors of single shot PVI with the novel RFB catheter. Methods In this observational study consecutive patients with drug refractory paroxysmal or persistent atrial fibrillation (AF) undergoing first-time PVI were enrolled in two high-volume ablation centers. All procedures were conducted in conjunction with a 3D-mapping system. Clinical, procedural and ablation parameters were systematically analyzed. Results 105 patients (58% males; 52% paroxysmal AF, 68 ± 11.3 mean age, left atrial volume index 38.6 ± 14.8 ml/m2) were included. 241/412 (58.5%) pulmonary veins were successfully isolated with a single shot (SS), with a time to isolation of 11.6 ± 8 s. Total number of radio frequency applications was 892 (mean 2.2/PV), resulting in successful isolation of 408/412 (99%) PVs at the end of the procedure. Mean electrodes’ impedance drop was significantly higher in the SS-PVI compared to the non-SS applications (21.5 ± 6.6 vs. 18.6 ± 6.5 Ohm). Concordantly, higher temperature rise was observed in the SS versus non-SS applications (10.9 ± 4.9°C vs. 9.6 ± 4.7°C). Conclusion In this multicenter real-world study, mean impedance drop and temperature rise emerged as valid predictors for SS-PVI with the novel RFB catheter. These parameters may help to guide efficient usage of the new RF balloon.

Funding Acknowledgements Type of funding sources: None. Background Pulsed-field ablation (PFA) integrated into a pentaspline catheter is a novel single shot device to perform pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF). While initial data demonstrated high safety and efficacy, long-term PVI durability and reconnection patterns are unknown. Here, we analyzed findings from repeat ablation procedures after index PFA compared to cryoballoon ablation (CBA) based PVI. Methods We prospectively included consecutive patients with index PVI applying PFA (n=161) or CBA (n=302) who underwent repeat ablation due to symptomatic recurrence of AF or atrial tachycardia (AT) after a blanking period of 3 months. All repeat procedures were performed with a 3D mapping system and RF energy. Results We identified a total of 14 patients after previous PFA and 23 patients after previous CBA. PV reconnection was detected in 9/14 (64%) patients after PFA and in 16/23 (70%) after CBA (p=1.000). A total of 24/55 (44%) vs. 34/92 (37%) initially isolated PVs demonstrated electrical reconduction (p=0.487) after PFA and CB ablation. In both groups the right inferior PV was reconnected most frequently (9/24 (38%) patients after PFA and 10/34 (29%; p=0.578) patients after CBA). Distribution of conduction gaps is shown in figure 1. All PVs were successfully reisolated. Repeat procedures after index PFA and CBA showed similar duration (115±32 min vs. 114±49 min; p=0.785), fluoroscopy time (13±4 min vs. 14±8 min; p=0.558) and number of RF applications (38±23 vs. 36±34, p=0.738). Conclusion During repeat AF/AT ablation after previous PFA- or CBA-based PVI a comparable incidence of PV reconduction gaps was found. Repeat procedure times and fluoroscopy exposure were similar. Randomized controlled trials and longer follow-up are necessary to draw further conclusions.

Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is the most effective rhythm control treatment for atrial fibrillation (AF) and benefits of early rhythm control (ERC) were recently demonstrated to be enhanced in patients with a high comorbidity burden (CHA2DS2-VASc ≥ 4). Incidence of pericardial effusion, a dreaded, potentially life-threatening complication that is associated with catheter ablation,has not been analyzed in larger patient cohorts stratified by CHA2DS2-VASc. Purpose To determine incidence of pericardial effusion and drained pericardial effusion related to left-atrial (LA) procedures in billing data between 2010 and 2021 of a large tertiary-care ablation center in Germany. Method Eligible cases of LA procedures were identified through analysis of coded OPS data between 2010 and 2021. This analysis included patients with atrial fibrillation undergoing an ablation procedure including a transseptal puncture and mapping in the left atrium, not for other supraventricular tachycardias. Analysis accounted for different versions of the ICD-10-GM and OPS-ICHI catalogues. Comorbidities and occurrences of complications were defined as derived variables on a case-wise analysis from documented ICD-10 and OPS codes. CHA2DS2-VASc-score was calculated from these derived variables and demographic parameters (age and sex). Results 8396 left atrial procedures in 6184 patients (35% female, 63.6±11.0 years old at index procedure) were analysed. Derived CHA2DS2-VASc was < 4 in 6529 (78%) and ≥ 4 in 1867 (22%) cases, median CHA2DS2-VASc was 2 (IQR 1;3) in the overall cohort. Non-paroxysmal AF was more prevalent in the CHA2DS2-VASc ≥ 4 group (62.5%) than in the overall cohort (56%) and in the CHA2DS2-VASc < 4 group (54%). Hypertension was the most common comorbidity in 5285 (63%) patients. Coronary artery disease was present in 1433 (17%), heart failure in 3757 (45%), chronic kidney disease in 899 (11%) patients, thereof 591 (7%) at a stage ≥ KDIGO III. Pericardial effusion was documented in 78/6529 (1.2%) in the CHA2DS2-VASc < 4 group. Thereof 35/78 (45%) required interventional or surgial drainage. In the CHA2DS2-VASc ≥ 4 group, pericardial effusion occurred in 21/1867 (1.1%) cases. Here, 10/21 (48%) required drainage. Occurrence of pericardial effusion did not differ between CHA2DS2-VASc-score stratified groups (χ2 p=0.805). Pericardial effusion requiring drainage was not different petween groups (χ2 p=0.822). Conclusion Patients with a higher comorbidity burden undergoing catheter ablation for atrial fibrillation in the past 10 years were not subject to an increased risk for pericardial effusion or drainage. This observation allows to perform highly efficient ablation procedures equally in patients with low and high comorbidity burden safely. Further analysis of the dataset regarding further left atrial ablation associated complications and their predictors will be provided.

Aims A novel irrigated radiofrequency (RF) balloon (RFB) for pulmonary vein (PV) isolation (PVI) was released in selected centres. We pooled the procedural data on efficacy and safety of RFB-PVI from two high volume German centres. Methods and results Consecutive patients with RFB procedures were enrolled. A 3D electroanatomical left atrial map guided the RFB navigation. Every RF delivery lasted 60 s, and duration was automatically reduced to 20 s for electrodes facing the posterior wall. Procedural data and post-procedural endoscopy data ( Conclusion The RFB showed a high efficacy allowing for fast PVI procedures, and 60% of PVs could be isolated at the first application. Most safety events were recorded during the learning phase. An oesophageal temperature monitoring is suggested: oesophageal lesions were detected in 8% of patients.

Aims Bipolar radiofrequency ablation (B-RFA) has been reported as a bail-out strategy for the treatment of therapy refractory ventricular arrhythmias (VA). Currently, existing setups have not been standardized for B-RFA, while the impact of conventional B-RFA approaches on lesion formation remains unclear. Methods and results (i) In a multicentre observational study, patients undergoing B-RFA for previously therapy-refractory VA using a dedicated B-RFA setup were retrospectively analysed. (ii) Additionally, in an ex vivo model lesion formation during B-RFA was evaluated using porcine hearts. In a total of 26 procedures (24 patients), acute success was achieved in all 14 ventricular tachycardia (VT) procedures and 7/12 procedures with premature ventricular contractions (PVC), with major complications occurring in 1 procedure (atrioventricular block). During a median follow-up of 211 days in 21 patients, 6/11 patients (VT) and 5/10 patients (PVC) remained arrhythmia-free. Lesion formation in the ex vivo model during energy titration from 30 to 50 W led to similar lesion volumes compared with initial high-power 50 W B-RFA. Lesion size significantly increased when combining sequential unipolar and B-RFA (1429 mm3 vs. titration 501 mm3 vs. B-RFA 50 W 423 mm3, P < 0.001), an approach used in overall 58% of procedures and more frequently applied in procedures without VA recurrence (92% vs. 36%, P = 0.009). Adipose tissue severely limited lesion formation during B-RFA. Conclusion Using a dedicated device for B-RFA for therapy-refractory VA appears feasible and safe. While some patients need repeat ablation, success rates were encouraging. Sequential unipolar and B-RFA may be favourable for lesion formation.

Background Pulsed field ablation (PFA) is a novel non-thermal energy source to conduct catheter ablation of atrial fibrillation (AF). However, real-world multi-center data regarding acute procedural efficacy and safety is sparse. Purpose To study acute procedural success and safety in patients undergoing PFA for catheter ablation of AF in a multicenter registry. Methods Consecutive paroxysmal and persistent AF patients undergoing PFA-based catheter ablation using a multispline catheter were enrolled. The cohort included first and repeat ablation procedures. Procedural parameters, acute success and in-hospital safety were evaluated. A follow-up of all patients was conducted. Results Five German centers enrolled a total of 154 patients undergoing PFA in this study. Mean age was 68±12 years, median CHA2DS2-VASc Score was 3 (Q1-Q3: 2–4). Patients suffered from paroxysmal AF (n=55; 36%), persistent AF (n=93; 60%) and consecutive atrial tachycardias (AT) due to previous CA (n=6; 4%). The median left atrial (LA) PFA and total procedure times were 33 (Q1-Q3: 24–53) and 90 (Q1-Q3: 73–116) minutes, respectively. Mean LA PFA fluoroscopy and total fluoroscopy times were 12.1±5.5 and 20.2±8.7 minutes. Of all 154 procedures, 130 (84%) were index ablation procedures with isolation of pulmonary veins (PVI) only and 24 (16%) were repeat procedures (including re-PVI and ablation of consecutive AT). Acute PV reconnection following primary PVI and the initial set of PFA-applications was found in 20/130 (15%) patients, necessitating additional PFA ablation. Finally, successful PFA-guided PVI was achieved in all patients. Additional PFA lesion sets (including LA posterior wall isolation, anterior ablation, mitral isthmus ablation) were applied in 17/154 (11%) patients. Complications occurred in a total of 6/154 (3.8%) patients (including three groin site complications, two pericardial tamponades, one transient coronary spasm without sequela). The follow up data is still being assessed and will be provided by the time of the ESC 2022 meeting. Conclusion PFA performed in patients with atrial fibrillation demonstrates high acute procedural success rates and a favorable safety profile in this first real-world multicenter registry. Funding Acknowledgement Type of funding sources: None.

Funding Acknowledgements Type of funding sources: None. Background Conventional mapping systems do not provide wall-thickness data, which is, however, known to be a determinant of radiofrequency ablation lesion transmurality. KODEX-EPD is a novel open-platform system, which uses dielectric tissue properties to provide real-time, high-resolution cardiac images, tissue characteristics and wall-thickness measurement to guide ablation procedures. Aim The aim of this case series was to report on our first experiences with KODEX-EPD regarding estimation of myocardial wall-thickness during catheter ablation of atrial fibrillation (AF). Methods We retrospectively analyzed consecutive patients undergoing radiofrequency AF-ablation in combination with KODEX-EPD. A high-resolution image from the left atrium (LA) and the pulmonary veins (PV) was obtained prior to ablation using a spiral mapping catheter in conjunction with KODEX-EPD. Wall-viewer points were collected within the LA, the PVs and the left atrial appendage (LAA) using a standard radiofrequency non-contact force ablation catheter and analyzed for wall-thickness applying the latest KODEX-EPD software version (1.5.0, not yet commercially released). Wall-viewer points were divided into a total of 10 segments (PV ostia, anterior wall, posterior wall, LA roof, LA floor, LAA and PV carina, details see Figure 1) in order to characterize wall-thickness in respective areas. Results A total of 570 wall-viewer points in 5 patients were analyzed. Most of the wall-viewer points were collected at the PV ostia as well as along the posterior and anterior wall (449/570, 79%). Actual myocardial atrial thickness ranged from 1.6 to 3.9 mm. Thickest myocardial LA-tissue was measured at the anterior wall (median 3.1 mm) and thinnest at the LA-roof (median 2.2 mm). Figure 2 gives a detailed distribution of wall-thickness measurements at different sites in the LA and PVs. Conclusion Atrial wall thickness can be estimated in patients during AF ablation procedures using dielectric tissue properties. Further evaluation and validation of the method are needed to study its reliability and utility for clinical practice.

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): FARAPULSE, Inc. Introduction Thermal energy sources damage the entire atrial tissue during pulmonary vein isolation (PVI) including cardiac nerves and ganglia. This induces a postinterventional increase in heart rate. Pulsed-field ablation (PFA), a new non-thermal energy source for PVI, primarily damages cardiomyocytes by electroporation. Whether use of PFA reduces damage to cardiac nerves and ganglia and influences postinterventional increase of heart rate is not known. Purpose We compared the acute effects of PFA with a pentaspline catheter and cryoballoon ablation (CBA) on secretion of circulating biomolecules reflecting cardiomyocyte and neuronal injury and postinterventional increase in heart rate to estimate damage to the cardiac autonomic nervous system and autonomic dysfunction after PVI. Methods Blood samples were taken before and after PVI in consecutive patients undergoing PFA and CBA. All patients participated in the TRUST registry. Serum concentrations of high-sensitive Troponin I (hsTropI, Immunoassay) and S100b (ELISA), a surrogate marker for neuronal injury, were quantified in blood samples taken prior to PVI and directly after PVI. Pre- and postinterventional heart rates were measured in ECGs and Holter-ECGs. Results Fifty-six patients underwent PVI, either by PFA (n=28, age 63 [54; 75] y, 64% males, 57% persistent AF) or CBA (n=28, age 71 [62; 78] y, 61% males, 54% persistent AF). All 112 blood samples were analyzable. Acute success of PVI was 100% in both groups without major complications, especially, no TIA and no stroke. After CBA, one patient suffered from phrenic palsy, which reversed after 3 months. HsTropI increased 3.3-fold more after PFA compared to CBA (625±138 vs. 185±42 pg/ml; p=0.004) suggesting more damage to cardiomyocytyes. S100b increased 2.9-fold less after PFA compared to CBA (21.1±3.7 vs. 61.2±8.1 pg/ml; p Conclusion This study in patients validates the experimental concept that PFA-based AF ablation leads to more specific damage to cardiomyocytes than to cardiac nerves and ganglia, reflected by lower S100B concentrations and no post-interventional heart rate increase compared to CBA.

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Study grant by EPD Solutions, Philips, Netherlands Background The occlusion tool was recently introduced for KODEX-EPD which is a novel dielectric high-resolution cardiac imaging system. The occlusion tool provides information about level of pulmonary vein occlusion by the cryoballoon (CB) in CB-based pulmonary vein isolation (PVI) ablation procedures for atrial fibrillation (AF). Purpose Assess effects of the introduction of the occlusion tool on procedural parameters during CB-PVI such as feasibility, acute efficacy and periprocedural safety of KODEX-EPD in different software versions. Methods and Results 173 consecutive patients (60/173 (35%) paroxysmal AF, 64±12 years, 66/173 (38%) female) underwent CB-PVI with EPD imaging between 08/2019 and 10/2021. 38/173 (22%) of all patients were treated using software version 1.4.6, 33/173 (19%) patients with version 1.4.6a, 41/173 (24%) patients with version 1.4.7 and 61/173 (35%) patients with the latest version 1.4.8. Acute PVI was achieved in all patients. No major periprocedural complications were documented. Software version showed significant effects on procedure duration, fluoroscopy duration and dose area product in ANOVA testing (Figure 1A-C). The largest effect in post-hoc testing was observed for fluoroscopy duration (Figure 1B). Tobit regressions were fitted to model effects of software version on the censored variable contrast volume. All software versions predicted used contrast volume (p Conclusion CB-based PVI in combination with its PV-occlusion tool is feasible and safe. The present data strongly suggests a steady positive development of the novel wide-band dielectric imaging and mapping system towards a fluoroscopy- and dye-reduced CB-based AF-ablation. Software versions were introduced sequentially. Therefore time (procedure date) needs to be considered as the most relevant confounder of the described results (e.g. due to a learning curve using the system). However, differentiated statistical testing could show that the results are mainly explained by software version and only much weaker by procedure date.

Funding Acknowledgements Type of funding sources: None. Introduction Pulsed-field ablation (PFA) is a novel energy source to perform pulmonary vein isolation (PVI) in patients with atrial fibrillation or cavo-tricuspid isthmus ablation (CTI) in patients with atrial flutter. Whether strong electrical fields generated by PFA could change the function and integrity of cardiac implantable electronic devices (CIED) is not known. Aim To assess the function and integrity of implanted devices before and after pulsed-field ablation. Methods This study included consecutive patients with CIED undergoing PFA at a large single center. Real-time CIED electrograms were recorded during PFA applications. CIED were interrogated before and after PFA assessing function (threshold, sensing), integrity (impedance), and arrhythmia episodes. Results We performed PFA in six patients (age 69±12 years, 1/6 female, left atrial diameter was 44±3 mm, left-ventricular ejection fraction 40±14%) for PVI in five patients with atrial fibrillation and CTI ablation in one patient with atrial flutter. All patients had CIEDs (one cardiac resynchronization device, two implantable cardioverter-defibrillators, three two-chamber pacemakers). Each patient undergoing PVI received 32 PFA applications of 2.5 s. (4x basket configuration and 4x flower configuration at each pulmonary vein), amounting to a total ablation time of 80 s and resulting in complete PVI in all five patients. For CTI ablation we applied 8 PFA applications of 2.5 s (20 s total ablation time) resulting in CTI blockade. Real-time intracardiac electrograms (iEGM) during PFA applications revealed sensing of single PFA application impulses in three patients and blanking of the iEGM in three patients. Postinterventional device testing revealed no changes in impedance, stimulation threshold or sensing. No leads were dislocated or damaged. No other device malfunctions occurred during the procedure, as well as no other major periprocedural complications occurred. Conclusion The function and integrity of pacemakers and defibrillators is not affected by PFA in our patient sample. Larger series are needed to confirm the apparent safety of PFA in patients with CIED.

Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) either by balloon devices or point by point radiofrequency (RF) and 3D mapping based catheter ablation forms the cornerstone of invasive atrial fibrillation (AF) treatment and has demonstrated high procedural success and encouraging long-term outcomes. Although equally effective cryoballoon (CB) based PVI offers shorter procedure duration as well as lower complication rates compared to RF based PVI. Beside the worldwide established Arctic Front Advance (AFA) cryoablation system a novel CB ablation system, POLARx was recently introduced. The POLARx CB incorporates unique features which may translate into improved efficacy and safety of CB based PVI. However, multicenter assessment of periprocedural efficacy and safety is lacking up to date. Methods From August 5th to october 12th 2020, a total of 317 patients with paroxysmal or persistent atrial fibrillation (AF) underwent POLARx CB based PVI in 5 centers from Germany and Italy. Acute efficacy and safety were assessed. Results In 317 patients (mean age 64±12 years, 209/317 (66%) paroxysmal AF) a total of 1256 pulmonary veins (PV) were identified and 1252 (99,7%) PVs were successfully isolated utilizing the mainly the short tip POLARx CB (82%). The mean minimal cryoballoon temperature was -57.9±7 °C. Real-time PVI was visualized in 72% of PVs. The mean procedure time 92±41 minutes with a mean fluoroscopy time of 15±10 minutes. Concerning periprocedural complications 1 (0.3%) cardiac tamponade successfully treated by pericardial puncture and 4 (1.3%) pericardial effusion without any intervention were detected. A total of 13 phrenic nerve injuries (4.1%) occurred during treatment of the right superior PV (9/13) and right inferior PV (4/13). Phrenic nerve injury recovered in 3/13 (23%) patients until discharge. Two minor bleeding of the groin (0.6%), 1 (0.3%) severe bleeding with intervention, 5 transient air embolism (1.6%) and 3 (0.9%) stroke / TIA has been observed. Conclusions In this large multicenter assessment the novel POLARx CB shows a promising efficacy and safety profile. Further studies are necessary to draw final conclusion.

Funding Acknowledgements Type of funding sources: None. Background Catheter ablation targeting isolation of the pulmonary veins (PVI) is the most effective treatment for atrial fibrillation (AF). Despite its high overall effectiveness, repeat AF ablations (re-do procedures, RDP) are often required to maintain sinus rhythm. Purpose Determine predictors for multiple and/or complex RDP, evaluate reference values for procedure duration and radiation exposure during index PVI (iPVI) and nth RDP in a large cohort. Methods and Results Data mining identified 934 (mean age 62.6 ± 12.3 years, 346 females) out of 6848 total AF ablation patients from a large German AF ablation center between 09/2008 and 09/2021 with an index PVI and at least one RDP. Analysis included 2152 procedures (out of 8750 total AF-related ablations). At iPVI, AF pattern was classified as paroxysmal AF (PAF) in 387 patients (41%). All others (59%) were classified as non-paroxysmal AF (Non-PAF). Non-PAF was significantly more frequent in males (64% vs. 49%, p iPVI was classified as PVI-only or PVI with additional substrate modification (SM). 724/934 patients (78%) received PVI-only as initial procedure. Of these, 572 (79%) had only 1 RDP, 116 (16%) had 2 RDP and 36 (5%) had 3 or more RDP. This distribution was 77%, 15% and 8% for 1, 2 and 3 or more RDP for patients with complex PVI as iPVI. An algorithm based on regular expressions classified all RDP as repeat PVI (Re-PVI) due to reconduction (PV reconduction), ablation of atrial tachycardia (AT) or SM, e. g. defragmentation of fractionated signals, or combinations. The results were manually quality-controlled. 798/934 (85%) patients required PV re-isolation due to PV reconduction, 298/934 (32%) required ablation for atrial tachycardia (AT) at least once during FU (Figure 1B). Comparing PVI-only iPVI patients with patients who received substrate modification during iPVI, significantly less patients with PVI-only iPVI had RDP for AT compared to those with SM during iPVI (27% vs. 50%, p Conclusion Redo AF ablations procedures are mainly required due to reconnected pulmonary veins or AT. Patients with PAF at iPVI are less likely to require more than one RDP which provides indirect support for early rhythm control in treatment of AF. SM at iPVI might be a predictor for occurrence of AT in the further course.

Funding Acknowledgements Type of funding sources: None. Introduction Pulsed-field ablation (PFA) and the multi-electrode radiofrequency balloon (RFB) are two novel ablation technologies to perform pulmonary vein isolation (PVI). It is currently unknown whether these technologies differ in lesion formation and lesion extent. Purpose We compared the acute lesion extent after PVI induced by PFA and RFB by measuring low-voltage area in high-density maps and the release of biomolecules reflecting cardiac injury. Methods PVI was performed with a pentaspline catheter (FARAPULSE) applying PFA or with the compliant multi-electrode radiofrequency balloon (HELIOSTAR). Before and after PVI high-density mapping with CARTO3 was performed. In addition, blood samples were taken before transseptal puncture and after post-PVI remapping. Serum concentrations of high-sensitive Troponin I (hsTropI) were quantified by Immunoassay. Results 50 patients undergoing PVI by PFA (n=26, age 71±10 y, 58% males, 58% persistent AF) or RFB (n=24; age 64±13 y, 54% males, 25% persistent AF) were evaluated. Acute PVI was achieved in all patients in both groups. Mean number of PFA pulses were n=34±5 and mean number RFB applications were n=8±3. Total posterior ablation area was bigger in PFA (19.0±6.2 cm²) than in RFB (9.0±2.2 cm²; p Conclusion Pulse-field ablation delivers larger acute lesion areas and higher troponin release upon successful pulmonary vein isolation than multi-electrode array balloon-based pulmonary vein isolation in this single-center series.

Background Data on the optimal treatment strategy for antiarrhythmic drug therapy (AAD) after atrial fibrillation (AF) catheter ablation are inconsistent. While AAD potentially stabilizes sinus rhythm, it also increases the patients' treatment burden. Methods Patients from the prospective German Ablation Registry (n=3275) discharged with or without AAD after AF catheter ablation were compared regarding long-term success, cardiovascular events and patient reported outcome. Results In patients with paroxysmal AF (n=2138) recurrence and rehospitalization rates did not differ when discharged with (n=1051) or without (n=1087) AAD (recurrence: adjusted odds ratio (OR) 1.13, 95% confidence interval (CI) [0.95–1.35]; rehospitalization: OR 1.08, 95% CI [0.90–1.30]). The reablation rate was higher and reduced treatment satisfaction was reported more often in those discharged with AAD (reablation: OR 1.30, 95% CI [1.05–1.61]; reduced treatment satisfaction: OR 1.76, 95% CI [1.20–2.58]). Similar rates of recurrences, rehospitalisations, reablations and treatment satisfaction were found in patients with persistent AF (n=1137) discharged with (n=641) or without (n=496) AAD (recurrence: OR 1.22, 95% CI [0.95–1.56]; rehospitalization: OR 1.16, 95% CI [0.90–1.50]; reablation: OR 1.21, 95% CI [0.91–1.61]; treatment satisfaction: OR 1.24, 95% CI [0.74–2.08]). The incidence of cardiovascular events and mortality did not differ at follow-up in paroxysmal and persistent AF patients discharged with or without AAD. Conclusion The rates of recurrences, cardiovascular events and mortality did not differ between patients discharged with or without AAD after AF catheter ablation. However, AAD should be considered carefully in patients with paroxysmal AF, in whom it was associated with a higher reablation rate and reduced treatment satisfaction. Funding Acknowledgement Type of funding sources: None.

Background Cryoballoon (CB)-based pulmonary vein isolation (PVI) currently requires to verify occlusion of each pulmonary vein (PV) using fluoroscopy and dye injection. Objective The current study evaluated whether the novel CB-occlusion tool integrated into the wide-band dielectric imaging system KODEX-EPD reliably verifies occlusion of PV according to a novel dye-injection based algorithm. Methods Consecutive patients suffering from symptomatic atrial fibrillation (AF) underwent CB-based PVI using the KODEX-EPD and the novel occlusion-tool (group I). To confirm accurate display of the PVs, selective PV-angiography was performed in the first half of the patients of group I (group Ia) in addition to a three-dimensional left atrial (LA) map using a spiral mapping catheter (Achieve, SMC1, Medtronic, MN, USA). PV-angiographies were waived for the following patients (group Ib). Procedural duration and radiation exposure were compared to a control group of patients undergoing conventional CB-based PVI. Results CB-based PVI was successful in 50/50 patients of group I (mean age 63±11 years, 18 paroxysmal (36%)) and 25/25 patients of group II (66±10 years, 9 paroxysmal (60%)). Concordance of PV-occlusion as assessed by either PV-occlusion-angiography or KODEX-EPD, was documented in 237/272 (87%) occlusion-analyses among 198 PVs (95% for left superior PV, 93% for left inferior PV, 86% for right inferior PV and 77% for right superior PV). In the final evaluation phase (group Ib) LA fluoroscopy times and dose area products were comparable to the conventional CB-ablation group (10.5±5 vs 8.8±4 minutes (p=0.23) and 403±425 vs 321±202 cGycm2 (p=0.44), whereas the amount of dye could be significantly reduced (group Ib: 31±10 ml vs group II: 70±20 ml, p Conclusion The novel KODEX-EPD PV-occlusion tool allows for accurate PV-occlusion assessment in the majority of PVs and a high acute success rate. The system has the potential to reduce dye and radiation exposure. This should be evaluated in controlled clinical trials. Funding Acknowledgement Type of funding sources: None.

Aims Arrhythmia recurrence is a common clinical problem in patients with pulmonary vein stenosis (PVS) following catheter ablation of atrial fibrillation. The study sought to analyse the management of arrhythmia recurrence in patients with PVS. Methods and results Retrospective analysis was performed on 29 patients with high-degree PVS. Follow-up contained clinical visits, Holter-electrocardiogram recordings and invasive pulmonary vein (PV) angiography and electrophysiological studies. Arrhythmia recurrence was observed in 18 patients (62%) after PVS formation. Fifteen of 18 patients (83.3%) with and 1 of 11 patients (9.1%) without arrhythmia recurrence had electrical PV reconnection (P = 0.0003). In 14 of 16 patients repeat pulmonary vein isolation (PVI) was conducted (radiofrequency ablation in 12 and cryoballoon ablation in 2 cases). Repeat PVI was successful in all PVs in nine patients and incomplete in five patients (failed attempt in two patients with stent implantation, no attempt in three patients with stenotic PVs). Freedom from arrhythmia recurrence was estimated at 56.3% [95% confidence interval (CI) 36.4–72.0%] after 24 months. At the end of the follow-up, complete PVI was documented in 19 of 23 patients (82.6%) with stable sinus rhythm and in 2 of 6 patients with arrhythmia recurrence (33.3%) (P = 0.0335). The Kaplan–Meier estimate of recurrence-free survival of restenosis after interventional PVS treatment was similar in patients without and with repeat ablation [75.6% (95% CI 57.0–94.3%) and 67.0% (95% CI 43.2–90.7%) after 500 days, P = 0.77]. Conclusions Pulmonary vein reconnection is the major driver of arrhythmia recurrence in PVS patients. Repeat PVI is feasible and does not lead to progression of PVS or restenosis if the procedure is carefully performed.

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Stiftung für Herzinfarkforschung Background Non-paroxysmal (NPAF) forms of atrial fibrillation (AF) have been reported to be associated with an increased risk for systemic embolism or death compared with paroxysmal AF (PAF). This study investigates the procedural safety and long-term outcomes of left atrial appendage closure (LAAC) in patients with different forms of AF. Methods Comparison of procedural details and long-term outcomes in patients (pts) with PAF against controls with NPAF in the prospective, multicentre observational registry of patients undergoing LAAC in Germany (LAARGE). Results A total of 638 pts (PAF 274 pts, NPAF 364 pts) were enrolled. NPAF consisted of 31.6% patients with persistent AF and 68.4% with longstanding persistent AF or permanent AF. In both groups, a history of PVI was rare (4.0% vs 1.6%, p = 0.066). The PAF group had significantly less history of heart failure (19.0% vs 33.0%, p 5 mm (0.0% vs 7.1%, p= 0.53) were numerically higher in the NPAF group. Overall, in-hospital complications occurred in 15.0% of the PAF cohort and 10.7% of the NPAF cohort (p = 0.12). In the one-year follow-up, unadjusted mortality (8.4% vs 14.0%, p = 0.039) and combined outcome of death, stroke and systemic embolism (8.8% vs 15.1%, p = 0.022) were significantly higher in the NPAF cohort. After adjusting for CHA2DS2-VASc and previous bleeding, NPAF was associated with increased death/stroke/systemic embolism (HR 1.67, 95%-CI: 1.02-2.72). Conclusion Atrial fibrillation type did not impair periprocedural safety or in-hospital MACE of patients undergoing LAAC. However, after one year, NPAF was associated with higher mortality and combined outcome of death, stroke and systemic embolism.