Arrhythmia Recurrence Research Articles

AB-452665-1 GENDER BASED DIFFERENCES IN SAFETY AND OUTCOMES OF CATHETER ABLATION PROCEDURE FOR ATRIAL FIBRILLATION

Studies have identified significant sex-based differences and disparities in the clinical presentation and treatment of atrial fibrillation (AF). Women are less likely to be referred for catheter ablation, are older at the time of ablation, and are more likely to have recurrence after ablation. It is important to note, however, that in most studies investigating AF ablation outcomes, the female cohorts were relatively small. The impact of gender on the outcome and safety of ablation procedures is still unclear due to the paucity of evidence on the topic. To investigate gender differences in outcomes and complications after AF catheter ablation, with a significant size female cohort in the study population In this retrospective observational study, patients undergoing first catheter ablation for AF from January 1, 2014, to March 31, 2021, were included. We investigated clinical characteristics, duration and progression of AF, number of electrophysiologist appointments (EP) from diagnosis to ablation, procedural data, and procedure complications. The primary endpoint of this study was arrhythmia recurrence, and the secondary endpoints were procedural complications and redo ablation. Total 1346 patients underwent first catheter ablation for AF during this period, including 896 (66.5%) male and 450 (33.4%) female patients (Table 1). Female patients were older at the time of ablation (66.2y vs 62.4y; p<0.001). Women had higher CHA2DS2-VASc scores (3 vs 2; p<0.001) than men, expectedly, as the female sex warrants an additional point. 25.3% female patients had persistent AF (PersAF) at the time of diagnosis vs 35.3% male patients (p<0.001). At the time of ablation, 31.8% female patients had PersAF as compared to 43.1% male patients (p<0.001), indicating progression of paroxysmal AF (PAF) to PersAF in both genders. Female group presented for more EP appointments and tried more antiarrhythmic drugs (AADs) than the male group before ablation (1.13 vs 0.98; p=0.002). Male and female patients had no statistically significant difference in (a) arrhythmia recurrence at 1-y post ablation (27.7% vs 30%; p=0.38) or (b) procedural complication rate (1.8% vs 3.1%; p=0.56). Female patients were older and had higher CHA2DS2-VASc scores compared to males at the time of AF ablation. Female patients tried more AADs and visited with electrophysiologists more leading up to ablation. 1-y arrhythmia recurrence rates and procedural complications were similar in both genders.

PO-02-135 DOES LA SIZE PREDICT OUTCOMES IN AF AND SYSTOLIC HEART FAILURE?

Significant left atrial (LA) enlargement often accompanies heart failure with reduced ejection fraction (HFrEF) and may determine the success of AF ablation. However, the impact of LA size on long-term outcomes remains unclear. We aim to determine the relationship between LA size and AF recurrence in patients with normal LV function (NLV) and HFrEF following AF ablation. Consecutive patients undergoing index AF ablation across 11 centres were stratified according to baseline LVEF (<50% or >50%). The impact of baseline LA size on 12-month AF recurrence was determined utilising continuous remote rhythm monitoring to detect arrhythmia recurrence and quantify AF burden. 360 patients were included (NLV=237, HFrEF=123). The HFrEF group (mean LVEF 34.9±8.3%) were younger (62±10 vs 65 ± 9 years, p=0.020), with larger LA size (LAVI 54.6±16.5ml/m2 vs 45.4±14.1ml/m2, p<0.001). Despite differences in LA size, freedom from AF was similar in those with and without HF (56% vs 54% respectively, Log Rank p=0.621, figure 1a). Similarly, AF burden did not differ between groups (median burden HFrEF 0% (0-1.1); NLV 0 (0-2.5), p=0.195). An age-matched 1:1 comparison of NLV and HFrEF (N=246) demonstrated no impact of baseline LA size on arrhythmia recurrence (p=0.579), despite larger LA in those with HFrEF (LAVI 54.6±16.5 vs NLV 45.0±15.0, p=0.0002). LA enlargement did not predict arrhythmia recurrence (HR 1.400, 95% CI 0.952-2.057, p=0.086) regardless of HF status (figure 1b). At 12 months, LV function normalised in 80% (LVEF>50%) of those with HFrEF (ΔLVEF: +19±13%, p<0.001) with a significant reduction in LA size (54.6±16.5 to 44.7±14.6ml/m2, p<0.001), comparable in those with and without AF recurrence (p=0.819). Baseline LA enlargement did not influence AF recurrence in those with or without LV recovery (HR 1.622 95% CI 0.702-3.748, p=0.258). LA enlargement did not determine the outcome of AF ablation in those with and without HFrEF. LA size is less useful in guiding patient selection for AF ablation in HFrEF

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.

PO-01-085 ATRIAL AND VENTRICULAR ARRHYTHMIAS IN A PATIENT WITH TUBEROUS SCLEROSIS

Tuberous Sclerosis is a genetic condition characterized with multiple non-cancerous tumor growths throughout the body. While arrhythmias are commonly seen in these patients, the predominance of arrhythmias appear to be irregular with atrial and ventricular ectopy as the most common manifestation. In our case we describe a patient with both organized atrial arrhythmias ( typical atrial flutter, atypical atrial flutter ) and monomorphic ventricular tachycardia. A pleasant 22 year old female with a pertinent medical history of Tuberous Sclerosis with multiple tubers present in the heart and brain presented to the electrophysiology clinic for evaluation regarding palpitations. The patient had a known history of prior ablation for typical atrial flutter twice before with recurrence of arrhythmias despite ablation and long term anti-arrhythmic therapy with flecainide. Implantation of an implantable loop recorder revealed evidence of likely typical flutter as well as monomorphic ventricular tachycardia. During the electrophysiology study, typical atrial flutter and atypical atrial flutter was succesfully induced and ablated. No ventricular arrhythmias could be induced. In addition intracardiac echocardiography revealed the presence of rhabdomyomas in the cavo-tricuspid isthmus and right side of the interventricular septum. NA Ablation across the CTI and a posterior line from the SVC to IVC resulted in tachycardia termination with no further induction of atrial arrhythmias and the presence of bidirectional block. No ventricular arrhythmias could be induced. Arrhythmias are a common manifestation in Tuberous Sclerosis. Our case highlights the arrhythmogenic nature of rhabdomyomas that can be present in both the atrium and ventricle. There is a scarcity of data available regarding the overall burden of arrhythmias in this patient population. In addition our patient is unique in that they presented with organized atrial and ventricular arrhythmias. The mechanism of the ventricular arrhythmia is unclear as it was not able to be induced, however, both atrial arrhythmias appeared macro-reentrant. While some histopathologic studies have suggested the presence of macro-renetrant circuits in this patient population, further large scale studies would be helpful to help characterize the mechanism of arrhythmias in this patient population.

PO-02-099 RADIOFREQUENCY CATHETER ABLATION OF ATRIAL TACHYCARDIA AND ATRIAL FIBRILLATION IN PATIENTS WITH PULMONARY HYPERTENSION. A SUBANALYSIS OF A PROSPECTIVE RANDOMIZED TRIAL

Atrial fibrillation (AF) and related atrial tachycardias (AT), including typical atrial flutter (AFL), are common arrhythmias in patients with pulmonary hypertension (PH). We have shown, in the multicenter randomized trial, that extensive radiofrequency catheter ablation of the arrhythmogenic substrate on top of selective ablation of clinical arrhythmia alone was not beneficial in terms of arrhythmia recurrence in patients with AF / AT and PH. Irrespective of the randomization scheme, we compared clinical outcomes in patients with AF versus those with organized ATs. Out of 74 patients (42 males; the median age of 70 [IQR 61; 75] years) with combined post- and pre-capillary or isolated pre-capillary PH enrolled at 3 national sites, two study subgroups were composed: the AF group and the AT group (including AFL). The primary endpoint was arrhythmia recurrence >30 s without antiarrhythmic drugs after the 3-month blanking period. Idiopathic pulmonary arterial hypertension was found in 41 (55%) patients, chronic thromboembolic PH in 22 (30%), and PH associated with lung disease or hypoxia in 11 (15%). The AF group included 38 patients, and AT group included 36 patients (23 with AFL). The median duration of the follow-up period was 13 (IQR: 12; 21) months. The primary endpoint occurred in 23 patients (61 %) with AF vs. 9 patients (25 %) with AT (hazard ratio: 0.3, 95% confidence interval: 0.14-0.66; p = 0.003), Figure. In contrast to AF and other organized ATs, typical AFL did not reoccur during the follow-up. Out of 4 patients with documented arrhythmia after cavotricuspid isthmus ablation, 2 had AF and 2 patients manifested atypical AFL. More details are in the Table. Patients with PH and organized ATs manifested less frequent reoccurrence of arrhythmia after catheter ablation than patients with AF. Despite new arrhythmia could manifest, catheter ablation seems to be the most effective in PH patients with typical AFL. ClinicalTrials.gov Identifier: NCT04053361. Funding: The study was supported by the Ministry of Health of the Czech Republic, Grant Nr. NV18-02-00027.

AB-452663-4 LEFT ATRIAL POSTERIOR WALL ABLATION USING PULSED FIELD ABLATION AS ADJUNCTIVE THERAPY DURING RE-DO PROCEDURES AFTER MULTIPLE FAILED PULMONARY VEIN ISOLATIONS USING THERMAL ENERGY

Pulmonary vein isolation (PVI) is the cornerstone for patients with atrial fibrillation (AF). Long-term efficacy is limited because of high PV reconnection rates. Ablation targets and strategies beyond PVI in re-do left atrial (LA) procedures have failed to improve outcome. Pulsed field ablation (PFA) has recently been introduced as a novel ablation technology. We report the first experience of re-do PVI with adjunctive LA posterior wall ablation (LAPWA) in patients with multiple failed LA procedures using thermal energy (RF /cryo). After high-density bipolar 3D voltage maps using a pentaspline diagnostic catheter, ablation was performed in conscious sedation using a steerable sheath and a pentaspline over-the-wire basket and flower PFA catheter. After re-do PVI (irrespective of PV status), the pentaspline catheter was visualized in the 3D mapping system. The posterior wall was ablated using the PFA catheter in the flower configuration (Figure). Projected catheter images overlapped approx. 30% between sites across the posterior wall. Per ablation site, 4 applications were administered. Post ablation, 3D voltage maps confirmed complete PVI and LAPWA. Bidirectional PVI was also documented using pacing. Procedural parameters, acute success, in-hospital safety and arrhythmia recurrence were assessed. Between Sept. 2021 and Nov. 2022, 17 patients were enrolled. Mean age was 68±8 years. Time since first AF diagnosis was 72±46 months. Mean number of previous LA procedures was 3±1. Acute PVI and LAPWA were 100% successful. Median procedural time was 160±62 min (including 47±10 min for pre and post mapping). LA dwell time of the PFA catheter was 46±19 min. Fluoroscopy time and dose area product were 24±09 min and 13±13 Gy.cm2. All patients tolerated this approach without procedural interruption. There were no acute or chronic complications. After a follow-up of 163±105 days, 12/17 (71%) patients were free of documented AF, atrial flutter or tachycardia. In patients with multiple failed LA ablations for AF, re-do PVI (irrespective of PV status) and LAPWA using PFA seems to be a safe and feasible approach with promising short-term results. Larger studies are needed to investigate long-term efficacy and safety in this patient group with otherwise very limited therapeutic options.

AB-452666-2 CATHETER ABLATION OF ATRIAL FIBRILLATION AND ATRIAL TACHYCARDIA IN PATIENTS WITH PULMONARY HYPERTENSION: A RANDOMISED STUDY

Atrial fibrillation (AF), typical atrial flutter (AFL), and other atrial tachycardias (ATs) are common in patients with pulmonary hypertension. Frequently, several supraventricular arrhythmias are successively observed in individual patients. We investigated the hypothesis of whether more extensive radiofrequency catheter ablation of the bi-atrial arrhythmogenic substrate instead of clinical arrhythmia ablation alone results in superior clinical outcomes in patients with PH and supraventricular arrhythmias. Patients with combined post- and pre-capillary or isolated pre-capillary PH and supraventricular arrhythmia indicated to catheter ablation were enrolled in 3 centres and randomised 1:1 into two parallel treatments arms: (A) Clinical arrhythmia ablation and (B) Clinical arrhythmia plus substrate-based ablation. The primary endpoint was arrhythmia recurrence >30 s without antiarrhythmic drugs after the 3-month blanking period. A total of 77 patients (mean age 67 ± 10 years; 41 males) were enrolled. The presumable clinical arrhythmia was AF in 38 and AT in 36 patients, including typical AFL in 23 patients. During the median follow-up period of 13 (IQR: 12; 19) months, the primary endpoint occurred in 15 patients (42 %) vs. 17 patients (45 %) in the group B vs. A (hazard ratio: 0.97, 95% confidence interval: 0.49-2.0). There was no excess of procedural complications and clinical follow-up events including an all-cause death in group B. Extensive ablation, compared with a limited approach, was not beneficial in terms of arrhythmia recurrence in patients with AF / AT and pulmonary hypertension. ClinicalTrials.gov Identifier: NCT04053361. Funding: The study was supported by the Ministry of Health of the Czech Republic, Grant Nr. NV18-02-00027.

PO-02-125 EVALUATION OF A GENOME-WIDE AND PITX2 POLYGENIC RISK SCORE FOR THE PREDICTION OF ATRIAL FIBRILLATION RECURRENCE AFTER PULMONARY VEIN ISOLATION

Polygenic risk scores (PRS) were recently shown to be associated with preexisting atrial fibrillation (AF) and to be predictive of incident AF. Previous studies using limited PRS to predict recurrent AF following pulmonary vein isolation (PVI) showed inconsistent results. We sought to evaluate the association of PRS with AF recurrence following ablation using a genome-wide PRS combining >6 million single nucleotide polymorphisms (PRSAF) and, in a secondary analysis, a PRS limited to a locus involved in pulmonary vein development comprising the PITX2 gene (PRSPITX2). To assess whether a genome-wide PRS was associated with time to recurrence of atrial arrhythmia following a first PVI. We included patients from our hospital biobank who underwent genome-wide array genotyping and imputation, had successful PVI performed in our center with at least 1 year of follow-up and absence of moderate-severe structural heart disease. We computed PRSAF and PRSPITX2 using weights from Khera et al (PRS catalog ID PGS000016) and assessed their association with time to first atrial arrhythmia recurrence following a blanking period of 90 days using Cox proportional hazards models (including covariables listed in table 1). A total of 411 patients in our biobank were identified to have had PVI for paroxysmal or persistent AF between 2002 and 2020. Of these, 342 met inclusion criteria (fig. 1A). Over a median follow-up time of 6.06 years (IQR 2.73-10.2), a total of 218 patients (62%) experienced atrial arrhythmia recurrence (fig. 1C). AF type (persistent vs. paroxysmal) and left atrial diameter were significantly associated with arrhythmia recurrence in univariate and multivariate analyses (table 1). Neither PRSAF (fig. 1B) nor PRSPITX2 were associated with the primary endpoint (HR 1.04, p=0.6 and HR 1.02, p=0.8, respectively). Furthermore, neither PRS was associated with recurrence in a subgroup analysis restricted to 287 patients with paroxysmal AF. A genome-wide PRS comprised of >6million markers and a targeted PITX2 PRS were not significantly associated with time to first atrial arrhythmia recurrence following a first acutely successful PVI for paroxysmal or persistent AF. These findings are in line with recent studies assessing a limited PRS. Further studies are required to explore the potential role of genetic susceptibility to AF in predicting AF recurrence in the absence of pulmonary vein reconnection and in predicting AF burden as an endpoint for PVI efficacy.

PO-455617-16 EFFECTS OF ADDING POSTERIOR WALL ISOLATION TO PULMONARY VEIN ISOLATION IN PERSISTENT ATRIAL FIBRILLATION AND HEART FAILURE WITH REDUCED EJECTION FRACTION (HFREF)

Catheter ablation in AF and heart failure with reduced ejection fraction (HFrEF) is associated with improved left ventricular ejection fraction(LVEF) and survival compared with medical therapy. Previous non-randomized studies have shown high success rates with adjunctive ablation strategies beyond pulmonary vein isolation (PVI), including posterior wall isolation (PWI). To examine differences in arrhythmia outcomes between PVI alone versus PVI with PWI in patients with concomitant persistent AF (PsAF) and HFrEF CAPLA was a multi-centre, prospective, randomized trial involving PsAF patients assigned to PVI alone or PVI with PWI. This substudy included patients with HFrEF(LVEF<50% on echocardiography). The primary endpoint was freedom from any documented atrial arrhythmia of>30 seconds, after a single ablation procedure, off anti-arrhythmic therapy(AAD) at 12 months. 98 patients with PsAF and HFrEF(mean age 62.1+/-9.8 years, 79.5% males, median LVEF 35+/-13%). 46.9% underwent PVI with PWI. After 12 months, 58.7% with PVI and PWI were free from recurrent atrial arrhythmia off AAD vs 61.5% of patients with PVI alone (HR1.02, 95% CI 0.54-1.91, p=0.96). There were no significant differences in freedom from any atrial arrhythmia on/off AAD after multiple procedures (PVI with PWI 60.9% vs PVI 65.4%; HR1.12, 95%CI 0.58-2.16; p=0.73), freedom from symptomatic atrial arrhythmia on/off AAD after multiple procedures (PVI with PWI 69.5% vs PVI 75%; HR 1.23, 95%CI 0.58-2.62; p=0.59), or median AF burden at 12 months (PVI with PWI 0% [IQR 0-2.63] vs PVI 0% [IQR0-2.59]; p=0.78). Median LVEF improved in PVI with PWI(LVEF increased by19.3+/-12.9%,p<0.01), and PVI alone (LVEF increased by 18.2+/-14%, p<0.01), with no difference between groups(p=0.71). Normalisation of LV function(≥50%) occurred in 71.4% in PVI with PWI compared with 59.1% with PVI alone(p=0.26). Catheter ablation is associated with significant LVEF improvements in PsAF and HFrEF. However adding PWI to PVI did not improve freedom from arrhythmia recurrence nor recovery of LVEF.

PO-01-035 SIX-MONTH FOLLOW-UP AFTER PULMONARY VEIN ISOLATION USING PULSED FIELD ABLATION FOR PAROXYSMAL ATRIAL FIBRILLATION

Pulsed field ablation (PFA) has recently been introduced as a novel routine ablation technology for paroxysmal atrial fibrillation (PAF). Only a few small clinical studies have been published on the mid- and long-term outcome. Here, we present the six-month clinical outcomes of PFA in PAF. In PAF patients, PVI in conscious sedation using a steerable sheath and a pentaspline over-the-wire basket and flower PFA catheter was performed. In a subset of patients, pre- and post-ablation high-density bipolar voltage 3D maps (Carto 3D) were performed. Procedural parameters, acute success, in-hospital safety and arrhythmia recurrence were assessed over 6-month follow-up. Efficacy was evaluated by freedom from a 30-sec. recurrence of AF/atrial flutter (AFL)/atrial tachycardia (AT). Follow-up included 7-day Holter ECGs and/or telephonic interviews at days 90 and 180 after ablation. This study included a total of 108 patients (mean age: 65±10 years; 44% female). Mean CHA2DS2-VASc-score was 2.3±1,7. Median duration since first AF diagnosis was 21 [IQR: 3 to 58] months. Pre- and post-ablation high-density maps were performed in 36/108 (33%) of patients. Skin-to skin procedure time was 78±35 min. Fluoroscopy time and dosis area product were 19±7 min and 5.56±4.64 Gy.cm2, respectively. Left atrial dwell time of the PFA catheter was 27±11 min. Acute pulmonary vein isolation rate was 100% of PVs using PFA only. Primary adverse events occurred in 3.7% of patients (1 groin hematoma, 2 pericardial tamponades, 1 stroke with lethal outcome). Five patients were lost to FU. During a mean FU of 205±84 days, 81 of 103 patients (79%) remained free of any symptomatic or documented AF/AFL/AT episode after a single procedure. In 22 (21%) patients at least one episode of AF/AFL/AT was documented. In 6/22 (27%) patients, a re-do procedure was performed. In 2/6 (33%) patients, a reconduction of the PVs (1 LIPV, 1 posterior carina on both sides) was seen. In the remaining 4/6 (67%) patients, during re-do procedure typical or atypical flutter was treated, in presence of durable PV isolation. PVI using PFA results in a reasonable 6-month atrial arrhythmia recurrence rate and safety profile. The success rate may be reduced due to the long duration since first AF diagnosis. PV reconduction rate during re-do procedure was 33% in a limited number of patients.

AB-452643-4 EFFECTS OF ADDING POSTERIOR WALL ISOLATION TO PULMONARY VEIN ISOLATION IN PERSISTENT ATRIAL FIBRILLATION AND HEART FAILURE WITH REDUCED EJECTION FRACTION (HFREF)

Catheter ablation in AF and heart failure with reduced ejection fraction (HFrEF) is associated with improved left ventricular ejection fraction(LVEF) and survival compared with medical therapy. Previous non-randomized studies have shown high success rates with adjunctive ablation strategies beyond pulmonary vein isolation (PVI), including posterior wall isolation (PWI). To examine differences in arrhythmia outcomes between PVI alone versus PVI with PWI in patients with concomitant persistent AF (PsAF) and HFrEF CAPLA was a multi-centre, prospective, randomized trial involving PsAF patients assigned to PVI alone or PVI with PWI. This substudy included patients with HFrEF(LVEF<50% on echocardiography). The primary endpoint was freedom from any documented atrial arrhythmia of>30 seconds, after a single ablation procedure, off anti-arrhythmic therapy(AAD) at 12 months. 98 patients with PsAF and HFrEF(mean age 62.1+/-9.8 years, 79.5% males, median LVEF 35+/-13%). 46.9% underwent PVI with PWI. After 12 months, 58.7% with PVI and PWI were free from recurrent atrial arrhythmia off AAD vs 61.5% of patients with PVI alone (HR1.02, 95% CI 0.54-1.91, p=0.96). There were no significant differences in freedom from any atrial arrhythmia on/off AAD after multiple procedures (PVI with PWI 60.9% vs PVI 65.4%; HR1.12, 95%CI 0.58-2.16; p=0.73), freedom from symptomatic atrial arrhythmia on/off AAD after multiple procedures (PVI with PWI 69.5% vs PVI 75%; HR 1.23, 95%CI 0.58-2.62; p=0.59), or median AF burden at 12 months (PVI with PWI 0% [IQR 0-2.63] vs PVI 0% [IQR0-2.59]; p=0.78). Median LVEF improved in PVI with PWI(LVEF increased by19.3+/-12.9%,p<0.01), and PVI alone (LVEF increased by 18.2+/-14%, p<0.01), with no difference between groups(p=0.71). Normalisation of LV function(≥50%) occurred in 71.4% in PVI with PWI compared with 59.1% with PVI alone(p=0.26). Catheter ablation is associated with significant LVEF improvements in PsAF and HFrEF. However adding PWI to PVI did not improve freedom from arrhythmia recurrence nor recovery of LVEF.

PO-02-197 PREDICTORS OF ATRIAL FLUTTER RECURRENCE AFTER ATRIAL FIBRILLATION ABLATION: THE CRUCIAL ROLE OF STRUCTURAL AND MORPHOLOGICAL LEFT ATRIAL REMODELING

Recurrence of supraventricular tachyarrhythmias after catheter ablation of atrial fibrillation (AF) is common, representing 30% of patients. Although AF recurrence occurs mostly, 10% of the patients face arrhythmia recurrence through atypical atrial flutter (AFL). The diagnostic and therapeutic management of atypical AFL is challenging. Predicting atypical AFL after AF catheter ablation is critical. To identify morphological and structural predictors of recurrence in the form of atypical AFL compared to AF based on Late Gadolinium Enhancement Cardiac Magnetic Resonance (LGE-CMR). From January 2013 to December 2021, 56 patients facing post-AF-CA atypical AFL were included in the monocentric and retrospective cohort. 112 patients with AF recurrence were randomly included in the cohort from the general database. Pre-procedure LGE-CMR was post-processed for every patient to assess global and regional left and right atrial (LA, RA) fibrosis quantification using an image intensity ratio > 1.32 as fibrosis. Sphericity was calculated as the percentage of similarity with respect to a sphere, and the volume of LA and RA were calculated. 168 patients who had faced supraventricular arrhythmia recurrence after AF-CA were included in the monocentric retrospective cohort. They were mainly male (72.1%), with a median CHADS-VASc score of 1.4 +/- 1.3, a number of previous CA of 2,2 +/- 0.4, and a biatrial dilation (LA volume index of 53.5 ml/m2, RA volume index of 59.6 ml/m2). An age superior to 65 (OR=6.61, CI95%:2.18-14.41, p<0.01), the number of previous CA procedures (OR=3.03, CI95%:1.17-7.81, p=0.02), a history of management of invasive additional lines (OR=2.48, CI95%:1.01-6.27, p=0.05), an elevated LA sphericity (OR=1.33, CI95%:1.11-1.59, p<0.01) and an increased LA fibrotic burden (OR=1.03, CI95%:1.00-1.07, p=0.04) independently predicted the occurrence of atypical AFL compared with AF recurrence after AF-CA (Figure). Specifically, an increased amount of fibrosis in the lateral LA zone area (OR=1.03, CI95%:1.01-1.04, p<0.01)] was an independent predictor of recurrence in the form of atypical AFL compared with AF recurrence (Table). The structural LA remodeling of AE, including LA fibrosis and LA sphericity, is a predictor of recurrence in the form of atypical atrial flutter compared with AF recurrence after AF-CA.

PO-02-042 SAFETY AND EFFICACY OF VERY HIGH-POWER SHORT-DURATION TEMPERATURE-CONTROLLED ABLATION FOR THE TREATMENT OF PERSISTENT ATRIAL FIBRILLATION

Ablation targets of persistent atrial fibrillation (AF) remain poorly understood nowadays: due to structural alterations of the left atrium, isolation of the pulmonary veins alone has proved ineffective. New ablation targets such as the posterior wall, coronary sinus, and left atrial appendage were then sought. A new catheter (QDOT Micro) has recently been released which has the potential to increase the safety and efficacy of the procedure: it is connected to a new radiofrequency (RF) generator which allows for temperature controlled ablation by reducing power and increasing irrigation with the increase in tissue temperature and allows to deliver power up to 90 W for few seconds (vHP-SD). Evaluate safety and efficacy of posterior wall vHP-SD ablation for patients with persistent AF We enrolled 29 patients treated with catheter ablation of persistent AF. Pulmonary vein isolation was performed in all patients. Substrate mapping of the posterior wall of the left atrium was subsequently performed in sinus rhythm with a multipolar catheter (Pentaray) and pathological potentials were eliminated with RF 90 W for 4 sec duration (vHP - SD). AF, atrial flutter and atrial tachycardia recurrences were identified by in office follow-up, 12-lead ECG, and dynamic Holter ECG. The treated patients have a median age of 63±10 years, 25 (86%) are male. Mean left atrial volume is 44.9 ± 17 ml/m2. 25 (86%) patients had never undergone catheter ablation before. Total mean procedure time is 75 ± 10 minutes, mean fluoroscopy time is 8 ± 5 minutes. Pulmonary veins isolation and posterior wall isolation was achieved in 100% of patients. There were no complications such as atrioesophageal fistula, phrenic nerve palsy, pericardial effusion and/or cardiac tamponade, pulmonary vein stenosis, or arteriovenous fistula. Patients free from arrhythmic recurrences are 69% after 8 months mean follow-up. The results demonstrated the clinical feasibility and safety of posterior wall vHPSD ablation for persistent AF using this new temperature-controlled catheter without intraprocedural and periprocedural complications at follow-up. However, this remains a single center experience in a small group of patients. Comparative trials involving greater number of patients with long-term follow-up are necessary to definitive results.

Prognostic implication of early recurrence after cryoballoon ablation in patients with atrial fibrillation.

It remains uncertain whether the implication of early recurrence and blanking period can be applied to patients with atrial fibrillation (AF) treated with cryoballoon ablation (CBA). We aimed to explore the prognostic value of early recurrence in patients with AF treated with CBA. We studied consecutive AF patients who were treated with CBA between April 2019 and September 2020 in two tertiary medical institutes and followed for up to 12months. The endpoint was the late recurrence of atrial arrhythmia, including AF, atrial flutter, and atrial tachycardia, following a 90-day blanking period. Atrial arrhythmia during the blanking period was defined as early recurrence and was not considered as an endpoint. This study included 406 patients with AF who underwent CBA. During the follow-up, 147 (36.2%) cases of late recurrence were observed. Of the 104 patients with early recurrence, 85 experienced late recurrence during follow-up. Early recurrence was associated with an increased risk of late recurrence in the univariate and multivariate analyses (P < 0.001). When we classified the patients into paroxysmal AF and persistent AF groups, early recurrence was still significantly associated with a higher risk of late recurrence (P = 0.005 and P < 0.001, respectively). Early recurrence after CBA was an independent risk factor for late recurrence in all patients as well as in those with paroxysmal AF and persistent AF. Therefore, further prospective studies could be considered to verify the risks and benefits of early rhythm control in patients with early recurrence.

PO-04-048 LYME CARDITIS PRESENTING AS ACCELERATED JUNCTIONAL RHYTHM IN ADULT PATIENT

Lyme carditis occurs in 1.5%-10% untreated patients infected with Borrelia burgdorferi in United States and usually manifests as varying degrees of atrioventricular (AV) block, myopericarditis, and degenerative valve disease. Several cases of junctional tachycardia have been reported in children with Lyme disease, but there have not been any cases reported in the adult population. Here, we report a case of accelerated junctional tachycardia in a 42-year-old woman with Lyme carditis. To describe a case of a Lyme carditis presenting as accelerated junctional rhythm in a 42-year-old patient. N/A A 42-year-old woman with no significant past medical history presented with complaints of palpitations and lightheadedness. She had a tick bite on her left anterior upper thigh one month prior while working in her yard. The tick was removed after about 3 hours. At that time the patient had no fevers, arthralgias or rashes; however, a month later she developed symptoms of palpitations and lightheadedness. A 12-lead ECG showed accelerated junctional rhythm with AV and VA dissociation and was otherwise normal (Fig 1A). Her primary care physician conducted Lyme serology, which came back positive for both IgG and IgM. A diagnosis of Lyme carditis was made, and the patient was admitted to the hospital for IV antibiotics. Repeat ECG showed sinus with PR prolongation to 252 ms along with episodes of accelerated junctional rhythm (Figure 1B and 1C). She was started on intravenous ceftriaxone with continuous cardiac monitoring. Echocardiogram showed no abnormalities. A peripherally- inserted central catheter line was placed for a 4-week course of ceftriaxone. Her PR interval normalized within 2 weeks of treatment with no junctional rhythm or heart block on serial ECGs and Holter monitors (Figure 1D). Follow-up over the next year showed no recurrence of symptoms or arrhythmias and no other cardiac sequelae. To the best of our knowledge, accelerated junctional rhythm has not been previously reported in the setting of Lyme disease in adult patients. Herein, we report a case of a Lyme carditis presenting as symptomatic accelerated junctional rhythm in a 42-year-old patient, likely caused by inflammation of AV nodal tissue.

PO-04-039 DIELECTRIC IMAGING-GUIDED ULTRA-LOW TEMPERATURE CRYOABLATION FOR ATRIAL FIBRILLATION

Ultra-low temperature cryoablation(ULTC) can be used to create transmural ablation lesions in the left atrium (LA). With a circular catheter configuration, this energy modality can be used to create continuous ablation lesions around the pulmonary veins(PVs). The same catheter configuration can be used to isolate the posterior wall(PW) by creating multiple overlapping circular ablation lesions. Isolation of the PVs and the PW can be assessed using pacing maneuvers. Three-dimensional voltage mapping may provide additional information on the extent of the ablation lesions. A recently introduced dielectric imaging-based mapping system can be used to generate voltage maps and to visualize the ULTC ablation catheter. To evaluate the feasibility of ULTC, guided by dielectric imaging-based electroanatomic mapping. Patients with atrial fibrillation were consented for catheter ablation with the iCLAS cryoablation system(Adagio Medical, Laguna Hills, USA). Ablation included isolation of the PV’s and LA PW if deemed necessary. The KODEX-EPD system(EPD Solutions, Best, the Netherlands) was used in conjunction with a circular mapping catheter to create pre- and postablation voltage maps. If the postablation voltage map revealed incomplete ablation lesions, additional energy applications were applied. Patients visited the outpatient clinic at 3 months post ablation. All patients were enrolled in a prospective registry study that was approved by the local ethics committee. Six patients (4 male, 4 persistent AF, age 66±7 years, LAVI 38±14ml/m2) were treated. The PVs were targeted in all patients, while the PW was targeted in 5 patients. A postablation voltage map was generated in 5 patients, which revealed incomplete PV isolation in 2 patients and incomplete PW isolation in 1 patient. Additional ablation in these patients resulted in acute electrical isolation of all targets. Isolation of the PVs was achieved using a median of 11[IQR:9-15] energy applications and 11[8.5-14] minutes of ablation. Isolation of the PW required 6[6-7] applications and 3[3-3.5] minutes of ablation energy. Total mapping time was 14.5[12.5-22.5] minutes, total fluoroscopy time was 16[12.5-18.5] minutes, and the total procedure time was 107.5[67.25-123.5] minutes. At 3 months follow up, only 1 patient had recurrence of atrial arrhythmia. Longer follow up is ongoing. Dielectric imaging-based electroanatomic mapping can be used to evaluate lesions of ULTC.

PO-02-201 OUTCOMES OF RADIOFREQUENCY ABLATION OF ATRIAL FIBRILLATION IN OCTOGENARIANS IN A MULTICENTER REGISTRY (REAL-AF)

Catheter ablation for atrial fibrillation (AF) has significantly increased in prevalence, including in an elderly population. However, some studies suggest that outcomes of AF ablation may be inferior in elderly patients. Real-world, multi-center data is minimal and may provide more insight on this possibility. To compare the outcomes of octogenarians versus non-octogenarians undergoing catheter ablation of AF in high volume centers. Patients undergoing radiofrequency ablation of AF were prospectively enrolled in a multi-center registry (REAL-AF) from January 2018 to May 2021. The cohort was divided into 2 groups, patients ≥ 80 years old (octogenarians) and patients < 80 years old (non-octogenarians). Baseline characteristics and procedural data were collected prospectively on all patients. Routine ambulatory monitoring was performed at 6- and 12-months and additionally as needed based on symptoms. Efficacy was assessed at 12 months. The primary outcome was freedom from symptomatic atrial arrhythmias lasting greater than 30 seconds after a 90-day blanking period. 71 patients were included in the octogenarian group and 1,134 patients in the non-octogenarian group. The proportion of patients with persistent AF was similar between the groups. Octogenarians were more likely to have lower BMI, hypertension, prior bleeding, and left atrial scar as assessed by electro-anatomic mapping system (EAM). Left ventricular ejection fraction and left atrial volume as measured on EAM were also similar among the groups. There was a trend towards increased recurrence of atrial arrhythmias in octogenarians (table 1). At 12 months, octogenarians were more likely to be on anti-arrhythmic drugs as well. However, there was no difference in procedure-related complications between the groups. When controlled for left atrial scar burden, there was no difference in outcomes between the two groups. Octogenarians undergoing ablation of atrial fibrillation are more likely to have recurrent atrial arrhythmias than younger patient; this difference seems to be associated with an increased likelihood of abnormal left atrial voltage in the elderly patients. Although octogenarians are considered a frail population, AF ablation maintained similar safety profiles and arrhythmia related healthcare utilization rates when compared to a younger population.

PO-01-194 A COMPARISON OF CLINICAL OUTCOMES FOR THREE DIFFERENT MODALITIES USED FOR PULMONARY VEIN ISOLATION IN PATIENTS WITH ATRIAL FIBRILLATION

Pulmonary Vein Isolation (PVI) represents the cornerstone in atrial fibrillation ablation. The two most frequently used technologies for PVI are radiofrequency (RF) and cryoablation (CB). More recently, laser balloon (LB) has emerged as a promising therapy. Studies comparing all three modalities are lacking. We sought to compare clinical outcomes of RF, CB, and LB ablation in patients with atrial fibrillation from a prospective multi center registry. Between January 2018 and December 2021 912 patients from 3 U.S. centers underwent PVI catheter ablation with either RF, CB, or LB. Baseline clinical characteristic and procedural data were obtained (table). Patients were followed for 1 year. The primary outcome was time to atrial fibrillation. Secondary outcomes were time to any arrythmia and time to anti-arrhythmic drug therapy after the 90-day blanking period. A total of 912 patients were enrolled during the study. There were no significant differences at baseline between the groups with regards to sex, age, and prior cardiac history. 331 (36%) patients underwent PVI with CB, 227 (25%) underwent PVI with LB, and 354 (39%) underwent PVI with RF. There was no significant difference in time to recurrence of atrial fibrillation across treatment groups at 180 days (p=0.635) and at 360 days (p=0.425) (Figure). After 360 days there was a trend towards less recurrence of atrial arrythmias in the LB group vs the CB group (p=0.096). Time to use of AADs after the 90-day blanking period was significantly higher in the RF group after 360 days (p=0.009). In the cohort, atrial fibrillation was significantly associated with severe LA dilation [HR 1.841 (95%CI 1.044 to 3.247); p=0.035] and paroxysmal type of AF [HR 0.66 (95% CI 0.45 to 0.98); p=0.038]. The most common complication was groin hematoma. No atrioesophageal fistulae were observed. Death occurred in one patient unrelated to procedure. In this prospective cohort study, recurrence of atrial fibrillation was similar between all modalities at 1 year. There was a trend towards lower recurrence of atrial arrhythmia at 1 year in the LB group compared to the CB group. Patients who underwent RF PVI were more likely to be initiated on AAD therapy after the 90-day blanking period. Predictors of recurrence of AF included a severely enlarged LA and paroxysmal type of AF. Similar rates of procedural complications were seen across all treatment groups.Tabled 1Patient CharacteristicsCharacteristicOverallCryo, NLaser, NRF, Np-valueAge656566650.3Male Sex5572311861400.051Hypertension6812391652770.12Diabetes2006353840.3Coronary artery disease1926452760.6Stroke662511300.2Congestive heart failure168121128135<0.001AAD therapy4191391101700.6Procedure time (min)126121128135<0.001Vascular complications30030.12Post procedural stroke1003>0.9Phrenic nerve palsy72410.13Hematoma3085170.11Death10110.2 Open table in a new tab

PO-03-002 OUTCOMES OF CRYOBALLOON ABLATION COMPARED TO RADIOFREQUENCY ABLATION FOR PULMONARY VEIN ISOLATION AND LEFT ATRIAL POSTERIOR WALL ISOLATION IN PATIENTS WITH PERSISTENT ATRIAL FIBRILLATION – A SINGLE CENTER EXPERIENCE

Among patients with persistent atrial fibrillation (AF), there is limited data to support posterior wall isolation (PWI) in addition to pulmonary vein isolation (PVI) to decrease rates of recurrence in persistent atrial fibrillation. There is emerging data to suggest the recurrence rate of atrial fibrillation with cryoballoon ablation is lower in comparison to radiofrequency ablation in patients who underwent contaminant PVI and PWI. To evaluate recurrence rates of AF in patients with persistent AF with concomitant PVI and PWI with cryoballoon ablation in comparison to radiofrequency ablation at single a center. From December 2020 to August 2022, 25 and 98 patients with persistent AF who underwent contaminant PVI and PWI with cryoballoon and radiofrequency ablation, respectively, were included. Patient demographics and recurrence rates were retrospectively analyzed (Table). After mean follow-up of 13 months, recurrence of atrial arrhythmia was lower with cryoballoon ablation than with radiofrequency ablation, which was not statistically significant (2 of 25 [8%] vs. 14 of 98 [14%], p-value 0.52). Both patients in cryoballoon ablation group had recurrent atrial fibrillation. In the radiofrequency group, 11 of 14 (79%) patients had recurrent atrial fibrillation, and 3 of 14 (21%) reoccurred with an atypical atrial flutter. Three patients in the radiofrequency group underwent repeat ablation procedure after recurrence. Repeat electroanatomic mapping demonstrated: focal reconnection in PVI (patient 1), PWI (patient 2), and a mitral annular flutter (patient 3). Among patients with persistent atrial fibrillation, there was a trend towards a lower rate of atrial arrhythmia recurrence with cryoballoon ablation in comparison to radiofrequency ablation in patients who underwent concomitant PVI and PWI. Larger studies are needed to evaluate these findings.Tabled 1CryoballoonN= 25RFN = 98P-ValueBASELINE CHARACTERISTICSAge (mean)69.4 (+/- 9.6)65.6 (+/-8.9)0.33Female12 (48%)31 (32%)0.13BMI (kg/m2)29.1 (+/-4.9)30.0 (+/-6.5)0.56CHA2DS2-Vasc Score (mean)2.5 (+/-1.3)2 (+/-1.6)0.48Mean LA Volume (mL/m2)53 (+/-22)47 (+/-17)0.57Beta-Blockers18 (72%)80 (90%)0.64Anti-Arrhythmic Medications7 (28%)29 (30%)0.47Oral Anticoagulation25 (100%)98/98 (100%)-Diabetes4 (16%)21 (21%)0.55Heart Failure13 (52%)36 (37%)0.16Coronary Artery Disease2 (8%)19 (19%)0.17Cerebrovascular Accident2 (8%)3 (3%)0.78Hypertension20 (80%)72 (73%)0.51Sleep Apnea9 (36%)35 (35%)0.97COPD3 (12%)5 (5%)0.12RECURRENCE RATE2 (8%)14 (14%)0.52 Open table in a new tab

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

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