Catheter Ablation Research Articles

Incidence of acute pericarditis after pulsed-field ablation for the treatment of atrial fibrillation

Abstract Introduction Pulsed-field ablation (PFA) has emerged as a novel treatment strategy for patients with atrial fibrillation (AF). While traditional thermal ablation modes such as radiofrequency energy or cryoballoon energy showed an acute pericarditis rate of 0.5 – 4%, little is known about the incidence of acute pericarditis after PFA. Purpose To assess the incidence of acute pericarditis using PFA for the treatment of AF. Method Patients undergoing catheter ablation for AF using PFA were consecutively enrolled in a prospective registry in a tertiary referral center between January 2022 and January 2024. After PFA, all patients received a clinical assessment for cardiothoracic symptoms including cardiac auscultation, 12-lead ECG and transthoracic echocardiography. A clinical diagnosis of acute pericarditis was established according to the 2015 European Society of Cardiology (ESC) guidelines by the presence of at least 2 of the following criteria within 90 days after PFA: 1) pleuritic chest pain; 2) friction rub; 3) new widespread ST-elevation or PR depression on ECG; 4) pericardial effusion. Suspected acute pericarditis was diagnosed if 1 criterion was fulfilled. Results A total of 388 patients with AF (median age 67.5 years, 32% female) underwent pulmonary vein isolation using PFA. 0 (0%) patients fulfilled ≥ 2 ESC criteria required for diagnosis of acute pericarditis. Suspected acute pericarditis within 90 days after the procedure was found in 17 (4.4%) patients. 29 (7.5%) patients reported some sort of cardiothoracic symptoms (chest pain, chest tightness, chest discomfort, shortness of breath or pleuritic chest pain). Among them, 6 (1.5%) patients received anti-inflammatory drug treatment due to suspected pericarditis. 0 (0%) patients had a friction rub, 6 (1.5%) patients showed PR depression (no ST-elevation) and 5 (1.3%) patients demonstrated pericardial effusions. None of the pericardial effusions required drainage. Conclusion In this large cohort of patients undergoing PFA for AF, no patients suffered acute pericarditis according to current ESC criteria. Any type of cardiothoracic symptoms after PFA were noted in 7.5% of patients with 1.5% of patients requiring drug therapy.Graphical Abstract

Cluster-specific predictors of early rhythm control in contemporary European cohort of patients with atrial fibrillation: The EHRA-PATHS Project

Abstract Background Early rhythm control (ERC) using antiarrhytmic drugs, electrical cardioversion or catheter ablation for AF within a year from first diagnosis of atrial fibrillation (AF) has been shown to reduce the risk of major adverse outcomes compared to usual care, and the effects of ERC have been suggested to be consistent across all AF subgroups with different risk profiles. We aimed to identify cluster-specific predictors of ERC in pre-defined AF clusters in contemporary European EHRA-PATHS AF cohort. Methods The EHRA-PATHS AF cohort was derived from the three prospective EurObservational Research Programme (EORP) AF registries - General Pilot, General Long-term, and AF III registry. A two-step cluster analysis was performed. A hierarchical cluster analysis with 18 variables was used to identify the optimal number of clusters, followed by a K-means cluster analysis to determine variable cluster association. Cluster-specific predictors of ERC were identified using univariate and multivariate logistic regression analyses. Results Of 18,799 patients, AF was diagnosed within 1 year in 8088 (43.0%), and 3913/8088 patients (48.4%) were treated with ERC. Among the three clusters - Cluster 1 (younger healthier AF patients) compared with Cluster 2 (Elderly with less comorbidity, mostly non-cardiovascular) and Cluster 3 (Elderly with more comorbidity, mostly cardiovascular), see Table, ERC was significantly more often used in Cluster 1 compared with Cluster 2 and Cluster 3 (both P<0.001), and in Cluster 2 compared with Cluster 3. Cluster-specific multivariable predictors of ERC are shown in Table. In all three clusters, asymptomatic AF (EHRA score I) and Northern Europe residence were inversely associated with ERC, while Western Europe residence was positively associated with ERC in Cluster 2 and 3. In Cluster 1, low stroke risk and hypertension were positively associated with ERC, while dilated left atrium (LA) and reduced left ventricular ejection fraction (LV EF) were negative predictors of ERC. In Cluster 2, age ≥80 years, enlarged LA, and CHA2DS2-VASc ≥2 for males and ≥3 for females were negatively associated with ERC. In Cluster 3, age ≥75 years, cardiomyopathy, liver disease, dementia and reduced LV EF were negative predictors of ERC. Conclusion Our study of a large European AF cohort showed that likelihood for ERC was greater in younger and healthier AF patients, as well as in elderly from Western Europe, while ERC was significantly less likely with increasing age and comorbidity (especially cardiovascular diseases). These findings likely reflect the lack of high-quality evidence supporting aggressive ERC in high-risk patients with AF. With increasing body of evidence favouring ERC such patients, a shift towards less selective consideration of ERC in daily practice may be expected.

Comparative effectiveness of pulsed field ablation and cryoballoon ablation for atrial fibrillation: a systematic review and meta-analysis

Abstract Background Cryoballoon ablation (CBA) is a well-established technique for treating atrial fibrillation (AF), with a low complication rate related to cryoenergy-induced lesions. Pulsed Field Ablation (PFA) has emerged as a non-thermal alternative, with promising potential to further reduce complications. Purpose We aim to conduct a systematic review and meta-analysis comparing the efficacy and safety of PFA versus CBA in patients with AF. Methods We conducted a systematic search across PubMed, Embase, and the Cochrane Central Register of Controlled Trials to identify randomized controlled trials (RCTs) or observational studies published between 2013 and 2024 that compared PFA and CBA ablation techniques in patients with AF. Statistical analysis was carried out utilizing RevMan 5.1.7. Heterogeneity was assessed with I² statistics; p-values inferior to 0.05 and I²>25% were considered as significant heterogeneity. Results A total of 840 studies were screened in the initial search, and 26 studies were selected for full-text review based on inclusion criteria. Out of these, 8 observational studies involving 3,113 patients were included. Among these, 1,088 (34.9%) underwent PFA, while 2,025 (65.0%) underwent CBA. Periprocedural complications were significantly lower in patients who underwent PFA compared with the CBA group (RR 0.46; 95% CI 0.29 to 0.74; p=0.001; I²=1%; Fig. 1A). Furthermore, there was a significant reduction in procedure time in the PFA group (MD -8.21 min; 95% CI -13.74 to -2.69; p=0.004; I²=96%; Fig. 1B). However, no statistically significant difference was observed among groups regarding fluoroscopy time (MD 1.63 min; 95% CI -0.22 to 3.48; p=0.08; I²=92%; Fig. 2A), or recurrence of atrial arrhythmias after the blanking period (RR 0.84; 95% CI 0.68 to 1.04; p=0.12; I²=6%; Fig. 2B). Additionally, a subgroup analysis involving only propensity score-matched cohorts was conducted but didn’t show any statistical difference for any outcomes evaluated. Conclusion In this systematic review and meta-analysis, PFA was associated with a lower risk of periprocedural complications and a shorter procedure duration, compared to CBA in patients with AF. Additionally, it didn’t show a potential for reducing the recurrence of atrial arrhythmias, and the data regarding fluoroscopy time were inconclusive.Primary outcomesSecondary outcomes

Procedural findings and follow-up results of catheter ablation of atrial fibrillation in patients after radiation therapy for breast cancer

Abstract Backround Data on breast cancer radiation therapy (RT) associated atrial cardiomyopathy and its potential role in the pathophysiology of atrial fibrillation (AF) is very limited. Objectives To investigate the effect of breast cancer radiotherapy (RT) on atrial cardiomyopathy and its possible role in the pathophysiology of atrial fibrillation. What is the therapeutic success of antral pulmonary vein isolation (PVI) with possible substrate modifications (CFAE) in patients with breast cancer radiation therapy and paroxysmal or persistent atrial fibrillation. Methods We searched the institution’s data base for patients who received RT for breast cancer and underwent subsequently 3D mapping guided AF ablation. Intraprocedural mapping data and short- and long-term results of ablation were evaluated according to "no low voltage" and "low voltage" present. Low voltage amplitudes in bipolar electrograms were defined as <0.5 mV for endocardial maps created during SR and <0.3mV during AF. Ablation strategy comprised pulmonary vein isolation (PVI) ± additional substrate modification according to the mapping results. Follow Up (FU) was evaluated using repetitive 7-days Holter ECG and clinical visits. Results We included 45 patients (all female, 70.9±7.2 years) with paroxysmal or persistent AF (n=18 and n=27). In 3D mapping, 60% of the patients (27/45) showed left atrial low voltage (LV group) with the majority showing low voltage in the anterior wall of the left atrium (LA) in 18 of 45 patients (40%). PVI with ablation of complex fractionated signals (CFAE) was predominantly performed (18/27). After one ablation, 33.3% (9) of the patients in the LV group were recurrence-free and after an average of 1.9 ablations, freedom from recurrence was achieved in 21 patients with low voltage (77.8%). In 18 patients, no low voltage was detected (NLV group) and PVI only was performed in the majority (14/18). In this NLV group, 61.1% (11) of the patients were recurrence-free after one ablation and freedom from recurrence was achieved in 72.2% (13) after an average of 1.2 ablations. Conclusion Thoracic radiation therapy in patients with breast cancer can lead to low voltage in the LA with the predominant low voltage location being the anterior wall of the LA. An extended ablation strategy (PVI & CFAE) can show good treatment options in these patients with atrial fibrillation, with high freedom from recurrence after a mean of two ablation procedures.Freedom from recurrence after ablationCharacteristics of left atrium (LA)

Feasibility and efficacy assessment of a novel size-adjustable cryoballoon for ablation of atrial fibrillation in a multicenter clinical setting

Abstract Background The POLARx-FIT cryoballoon (CB) system introduces a unique feature, allowing the selection of two distinct balloon sizes within a single catheter. This innovation holds promise for treating larger pulmonary veins (PV), providing increased flexibility to achieve optimal occlusions. However, there is a scarcity of clinical data supporting its application in this context. Purpose To compare the benefits and safety of the new POLARx-FIT system to those of the existing POLARx system currently in use for PV isolation (PVI) in patients with atrial fibrillation (AF). Methods The first 140 consecutive patients who underwent CB-based PVI with the POLARx-FIT system were retrospectively compared with 300 consecutive patients treated with the POLARx system. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation was not available. The ablation endpoint was PVI as assessed by entrance and exit block. In the POLARx-FIT group the choice of balloon size (28 or 31 mm) was determined during the procedure while attempting to occlude each vein. Results Two-thousand one-hundred fifty-five cryo-applications (CBA) from 440 patients were analysed (300, 68.2% POLARx; 140, 31.8% POLARx-FIT). PVI was achieved with cryoablation only in all patients. The mean number of freeze applications per patient was similar between groups (5.0±1.4 in the POLARx-FIT vs 5.3±1.8 in the POLARx group, p=0.207) whereas the number of PVs treated in a single-shot fashion was higher in the POLARx-FIT group (444, 80.7% with one shot; 75, 13.7% with 2 shots; 31, 5.6% with more than 2 shots) than in the POLARx one (1168, 70.2% with one shot, p=0.0002; 294, 17.7% with two shots and 143, 8.6% with more than two shots). Among the POLARx-FIT cases, in 54.2% (n=298) of applications, the 31-mm diameter was employed as a first choice, while in the remaining 45.8% (n=252) of applications, the 28-mm diameter was adopted. A switch to a different balloon diameter was applied in 11.6% of cases. The first pass isolation (i.e. a single shot CBA to achieve PVI) was slightly higher when using a 31 mm diameter (n=250, 83.9%) than a 28 mm diameter (n=194, 77.0%, p=0.05). Three (0.7%) transient phrenic nerve palsy were observed (all in the POLARx group, 0.9%, p=0.554), with full recovery in the 48-h post procedure; no major procedure-related adverse events were reported at 30 days post-procedure. Conclusion In this first multicentric experience in a clinical practice setting, this novel cryo-balloon system proved to be safe and effective and resulted in a high proportion of successful single-freeze isolation. The intraprocedural flexibility of balloon size contributed to its versatility, leading to a variation in balloon diameter in about 12% of freeze applications.

Detecting epicardial connection through intercaval bundle using intra-atrial activation sequence during right pulmonary vein pacing

Abstract Background An epicardial connection (EC) through the intercaval bundle (EC-ICB) between the right pulmonary vein (RPV) and the right atrium (RA) is one of the reasons for the need of carina ablation for PV isolation. Purpose We evaluated the intra-atrial activation sequence during RPV pacing after failure of ipsilateral RPV isolation and sought to identify specific conduction patterns in the presence of the EC-ICB. Methods This study included 223 consecutive patients undergoing initial catheter ablation of atrial fibrillation. If the RPV was not isolated by circumferential ablation or reconnected during the waiting period, an exit map during mid RPV carina pacing was created. If the earliest site of the exit map was the RA, the patient was classified into the EC-ICB group. During the exit map, intra-atrial activation sequence and RPV-HRA time were evaluated. Results First-pass isolation of the RPV was not obtained in 36 patients (16.1%), and 22 patients (9.9%) showing reconnection. Among them, 12 patients were classified into the EC-ICB group and 28 patients into the Non-EC-ICB group after excluding multiple ablation lesion sets or incomplete mapping. Intra-atrial activation sequence showed different patterns between the two groups. RPV-HRA time was significantly shorter in the EC-ICB group compared to the Non-EC-ICB group (69.2 ± 15.2 ms v.s. 148.6 ± 51.2 ms. P<0.001), and RPV-HRA time<89.0ms was highly predictive for existence of the EC-ICB (sensitivity 91.7 %, specificity 89.3 %). Conclusions The EC-ICB can be effectively detected by intra-atrial sequencing during RPV pacing and RPV-HRA time<89.0ms was highly predictive.

Pulsed-field ablation for atrial fibrillation with a novel simplified protocol: the Swiss PFA dose multicenter study

Abstract Introduction Pulsed-field ablation (PFA) has emerged as a novel treatment technology for patients with atrial fibrillation (AF). So far, little is known about the optimal number of PFA applications per pulmonary vein (PV). The standard protocol for PFA, as per manufacturer’s recommendation, entails 8 applications per PV. Purpose To assess the optimal pulsed-field ablation dosing (simplified versus standard protocol vs. extended protocol). Method We prospectively enrolled patients undergoing their first PVI using PFA in three tertiary referral centers. The following PFA dose protocols were applied: In the simple PFA group, a novel simplified protocol for PFA was performed with only 4 applications per PV (2x in basket and 2x in flower configuration). In the standard PFA group, a standard protocol with 8 applications per PV (4x basket and 4x flower configuration) was applied and in the extended PFA protocol, an extended protocol with 12 applications per PV (4x basket and 8x flower configuration) was applied. Results 364 patients were included (32% female, median age 66 [IQR 58 – 73] years). Among these, 100 patients (36%) were in the simple PFA group, 180 patients (50%) in the standard PFA group and 84 (24%) patients in the extended PFA group. The median procedure duration, left atrial dwell time and the fluoroscopic time for the simple PFA, standard PFA and extended PFA group were 45 [interquartile range (IQR) 28 – 57] min vs. 54 [IQR 41 – 67] min vs. 63 [55 – 76] min (p < 0.001), 25 [IQR 12 – 38] min vs. 37 [IQR 27 – 50] min vs. 39 [29 – 55] min (p < 0.001), 9 [IQR 8 – 12] min vs. 11 [IQR 9 – 14] min vs. 9 [8 – 10] min (p < 0.001), respectively. A total of four procedural complications (two tamponades, one stroke, one temporary ST elevation) were observed for the standard PFA group and none for the simple or extended PFA group (p = 0.382). The recurrence rate of atrial arrythmias was 41 (23%) for the standard protocol, 11 (11%) for the simple protocol and 12 (14) % for the extended protocol over a median follow-up of 285 [IQR 173 – 478] days (p = 0.065). Conclusion A novel simplified PFA protocol resulted in significantly shorter procedure duration, left atrial dwell time and fluoroscopic time, without compromising procedural efficacy compared to the standard or extended protocol.Figure 1

Role of 3D-electro-anatomical mapping on procedural characteristics and outcomes in pulsed-field ablation for atrial fibrillation

Abstract Introduction While the utilization of dedicated 3D-electro-anatomical mapping (EAM) systems for catheter ablation of atrial fibrillation (AF) is crucial using radiofrequency, its potential benefits in pulsed-field ablation (PFA) remain uncertain. This is of particular interest, since some PFA ablation systems will soon be available with integrated 3D-EAM capabilities. Objectives To compare the procedural characteristics and outcomes of patients undergoing PFA for pulmonary vein isolation (PVI) with mapping and with no mapping. Methods We prospectively enrolled patients undergoing their first PVI at a tertary referral center. In patients undergoing PVI with mapping, a multipolar mapping catheter was used to create voltage maps during sinus rhythm pre- and post-ablation. In the non-mapping group PVI was confirmed by assessing entrance block via the PFA catheter. The first 30 cases with mapping were excluded to account for a potential learning curve. Results A total of 197 consecutive patients were included (age 65 [interquartile range (IQR) 58 – 72] years; indexed left atrial volume 40 [IQR 35 – 44] mL/m2). Among these, 127 patients (64%) underwent PVI with mapping and 70 patients (36%) with no mapping. The median procedure duration, left atrial dwell time and the fluoroscopic time for the mapping vs the non-mapping group were 55 [IQR 45 – 67] min vs. 28 [IQR 23 – 35] min (p < 0.001), 38 [IQR 30 – 49] min vs. 15 [IQR 11 – 21] min (p < 0.001), 11 [IQR 9 – 14] min vs. 8 [IQR 7 – 11] min (p < 0.001), respectively. In the mapping group in 9% (11/127 patients) at least 1 PV was incompletely isolated and required additional applications. Acute PVI success was 100%. There were two complications in the mapping group (one stroke, one coronary artery air embolism) and none were observed in the non-mapping group. The recurrence rate of atrial arrythmias during a median follow-up of 267 [IQR 164 – 419] days was 14% in the mapping group and 17% in the non-mapping group, p = 0.728. Conclusion In conclusion, the use of PFA with no mapping was associated with a significant decrease in procedural characteristics, while AF-recurrence was not significantly different. The routine use of mapping for PFA-PVI may not be needed.Figure 1

Long-term efficacy of concomitant surgical ablation for atrial fibrillation with cardiac surgery

Abstract Background Concomitant surgical ablation (SA) is recommended at the time of cardiac surgery in patients with atrial fibrillation (AF) but it is only performed in the minority due to perceived barriers such as increased risk, longer procedure duration and additional technical skills required [1,2]. Furthermore, long-term outcome reporting is limited to only a few high-volume centres. Purpose We sought to report on our centre’s 11-year experience with cardiac surgery and concomitant SA. Methods This was a retrospective observational study on 625 patients with AF who underwent SA in addition to other cardiac surgery at our centre between April 2011 and March 2022. Patients undergoing standalone SA were excluded. Complications were recorded up to 30 days post-procedure. Freedom from atrial tachyarrhythmias (ATA) was determined by electrocardiography, Holter monitoring and pacemaker interrogation at various time points, if available, with or without additional therapies for AF. Results Mean age was 69 +/- 9.9 years and the median duration of AF was 1.2 years (interquartile range 0.4-3.8), persistent in 79% of patients. The median left atrial volume index (LAVI) was 55 ml/m2 (interquartile range 43-71). Concomitant surgery included coronary artery bypass grafting (26%), mitral (68%), aortic (27%), tricuspid (21%) and/or other (5%). Biatrial Cox-Maze IV was performed in 51% of patients and the left atrial appendage was occluded in 74%. Major complications included 30-day mortality (3%), stroke (3%) and pacemaker implantation (4%). Freedom from ATAs was 80% (312/391), 64% (154/240), 53% (76/144) and 44% (33/75) at 1, 3, 5 and 7 years, respectively (Figure 1). Cox regression demonstrated diabetes mellitus, AF duration, persistent AF and LAVI as predictors of 7-year ATA recurrence. Conclusion Concomitant SA for AF has good early and acceptable longer-term rhythm outcomes with no significantly increased complication rate, which should encourage greater uptake of the procedure.

A meta-analysis of the safety and efficacy of pulsed-field versus conventional thermal ablation for atrial fibrillation

Abstract Background Since pulsed-field ablation (PFA) specifically targets myocardial tissue, it has become a cutting-edge substitute for radiofrequency (RF) and cryoablation. Purpose We aim to compare the safety and efficacy of PFA vs thermal ablation for AF ablation. Methods We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs) and observational comparative studies, which were retrieved by systematically searching: PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through September 2023. RevMan version 5.4 software was used to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI). Results Seventeen studies with a total of 2,255 patients were included. PFA was significantly associated with a decreased AF recurrence (RR: 0.65, 95% CI [0.51, 0.84], P= 0.0010) but not any arrhythmia recurrence (RR: 0.87, 95% CI [0.69, 1.09], P= 0.22). Also, PFA was significantly associated with decreased total procedure time (MD: -15.15, 95% CI [-20.23, -10.07], P< 0.00001) and heart rate (MD: -7.56, 95% CI [-12.78, -2.34], P= 0.005); however, there was no significant difference between PFA and thermal ablation in fluoroscopy time (MD: 2.83, 95% CI [-0.38, 6.04], P= 0.08). PFA decreased phrenic nerve palsy (RR: 0.38, 95% CI [0.15, 0.98], P= 0.05) and esophageal lesions (RR: 0.09, 95% CI [0.01, 0.69], P= 0.02); however, PFA was significantly associated with increased pericardial tamponade (RR: 6.14 with 95% CI [1.43, 26.33], P= 0.01). Conclusion PFA was significantly associated with decreased AF recurrence, heart rate, total procedure time, phrenic nerve palsy, esophageal lesion, and increased incidence of pericardial tamponade compared with thermal ablation. However, current evidence is mainly weighted by observational studies, requiring further large-scale randomized trials.Figure

Left atrial appendage volume estimated by artificial intelligence predicts atrial fibrillation recurrence after cryobaloon ablation

Abstract Background/Introduction The volume of the left atrial appendage (LAA), as measured in contrast-enhanced cardiac computed tomography (CCTA), has been previously reported as a predictor of long-term recurrence of atrial fibrillation (AF) following cryoballoon ablation procedures. Unfortunately manual assessment of LAA volume, is tedious and time-consuming, making it impractical for clinical practice. The recent advent of artificial intelligence (AI)-based methods offers a potential solution to this limitation. Purpose This study aims to evaluate the utility of LAA volume, as automatically measured by a state-of-the-art AI model for the fully automatic segmentation of LAA in CCTA, in predicting AF recurrence following cryoballoon ablation procedures. Methods We retrospectively analyzed a cohort of patients who underwent cryoballoon ablation for pulmonary vein isolation at our facility between 2010 and 2016. AF recurrence was determined through in-person visits and Holter monitoring at 3, 6, and 12 months post-ablation, followed by annual visits. The first three months post-ablation were considered a blanking period. An open-source deep neural network AI model [1] was utilized to perform automatic segmentation and calculation of LAA and left atrium (LA) volumes in. Receiver-operating characteristic curves were used to obtain optimal cut-off values for increased LAA and LA volumes. We then assessed the association of increased LAA and LA volume, and the LAA to LA volume ratio with recurrence-free survival using the Cox regression model. Results The cohort consisted of 212 patients (median age 62, inter-quartile range [IQR]: 55–65), with 25% having persistent AF before the procedure. Subjects were observed for a median period of 12 months (IQR: 12–36), with 70 of them (33%) experiencing a documented recurrent AF episode. The optimal thresholds for predicting AF recurrence were established as 9.8ml for LAA volume, 124ml for LA volume, and 0.086 for the LAA to LA volume ratio, respectively. An increased LAA volume demonstrated the strongest association with AF recurrence (hazard ratio [HR]: 2.6, 95% confidence interval [CI]: 1.55–4.2), followed by an increased LA volume (HR: 2.1, 95% CI: 1.3–3.4), persistence of AF (HR: 2, 95% CI: 1.2–3.3), and increased LAA to LA volume ratio (HR: 1.9, 95% CI: 1.1–3). Kaplan-Meier plots illustrating AF-free survival, are presented in Figure 1. After adjusting for age, persistent AF, left ventricular ejection fraction, and body surface area, all AI measurements remained significantly associated with a higher AF recurrence (Table 1). Conclusions Increased LAA volume, as assessed automatically by AI in CCTA, is a useful predictor of AF recurrence after catheter ablation for atrial fibrillation. The use of freely available, AI-assisted analysis of CCTA could be instrumental in assessing LAA volume, among other predictors, for long-term ablation success.Figure 1.

Impact of the underlying rhythm during cavotricuspid isthmus ablation on the incidence of future new-onset atrial fibrillation: insights from an international multi-centre registry

Abstract Background Radiofrequency catheter ablation of the cavotricuspid isthmus (RF-CTI) is the estabslished treatment of typical atrial flutter (AFL). After RF-CTI for AFL patients without previously documented atrial fibrillation (AF) may also develop AF. It is unknown whether the presence or absence of AFL at the time of ablation can predict the future occurence of AF. Purpose To compare baseline characteristics, procedural data, and long-term follow-up (FU) of patients with AFL. Methods Consecutive patients with documented AFL undergoing RF-CTI were enrolled in a multi-center registry in five centers in two countries between February 2017 and July 2023. For patients with AFL, entrainment mapping was performed for confirming CTI dependent AFL. Patients were categorized into two groups, those with AFL and those with sinus rhythm (SR) during RF-CTI. FU data were collected, including clinical assessments, 12-lead electrocardiogram (ECG) and 24-hour Holter-ECGs during each visit. Results Of the 949 subjects, 36% were excluded from the analysis due to a history of AF. A total of 574 patients were included (mean age 68 +/- 11 yrs, 14% females), 62% presented in AFL group and 38 % SR group during CTI. Median FU was 364 days. Patients in AFL group were older (P < 0.029), more likely to have diabetes (P = 0.026), and were less frequently treated with antiarrhythmic drugs (P < 0.001). In the first 12 months of FU, 40% of the patients underwent three FU examinations, while 77% of the patients underwent at least one 24-hour Holter-ECGs during FU. In the Kaplan-Meier analysis patients in AFL group significantly less often developed AF during FU (log-rank, P < 0.016, central ). In the multivariate Cox regression analysis, sinus rhythm during ablation (hazard ratio 1.474; 95% CI 1.043-2.084; P = 0.028), male gender (hazard ratio 1.722; 95% CI 1.116-2.658; P = 0.014) and coronary artery disease (hazard ratio 1.711; 95% CI 1.145-2.555; P = 0.009) were identified as predictors for the occurence of AF during FU. Conclusion Over a one year follow-up, new onset AF occurs significantly less frequently in patients with ongoing atrial flutter during RF-CTI ablation.

Maintenance of sinus rhythm is associated with lower incidence of stroke in patients with drug-refractory atrial fibrillation

Abstract Introduction Recent studies have demonstrated that early rhythm control for first-line treatment of atrial fibrillation (AF) improved cardiovascular outcomes. However, there is limited data regarding the long-term outcome of patients who failed antiarrhythmic drugs and who refuse radiofrequency catheter ablation (RFCA). Methods Patients with AF who were refractory to antiarrhythmic drugs and had refused further rhythm control attempts via RFCA were retrospectively identified and propensity-score matched with who had been treated with RFCA. The primary outcome of interest was all-cause mortality or ischemic stroke. Results A total of 169 patients who refused rhythm control with RFCA and propensity-score matched 169 patients who had been treated with RFCA were included for analysis. During a mean follow-up of 4.3[2.3;6.9] years, maintenance of sinus rhythm was more achieved in RFCA group (7 [4.1%] in Refuse group vs. 133 [78.7%] in RFCA group, p<0.001). the incidence of ischemic stroke was significantly higher in patients who refused RFCA compared with patients who underwent RFCA (24 [14.2%] vs. 6 [3.5%], log-rank p<0.001), but all-cause mortality was not significantly different (log-rank p=0.8). Refusal of attempted rhythm control via RFCA was an independent risk factor for ischemic stroke on multivariate Cox analysis (hazard ratio 3.2; 95% confidence interval 1.2 to 8.53, p=0.02). The risk of major adverse cardiovascular events (MACE) were also significantly higher in Refuse group (31 [18.3%] vs. 12 [7.1%], HR 3.83, 95% CI 1.57-9.37, p=0.003). Conclusion In patients with antiarrhythmic drug-refractory AF, maintenance of sinus rhythm was significantly different dependent on rhythm control via RFCA, therefore the risk of stroke was significantly higher in patients who refused rhythm control via RFCA compared with that of those treated with RFCA.

Haemolysis and acute tubular injury after pulsed field ablation compared to radiofrequency: An observational study

Abstract Background Pulsed field ablation (PFA) represents a novel promising non-thermal alternative in non-pharmacological treatment of atrial fibrillation (AF). However, infrequent cases of acute renal failure secondary to intravascular haemolysis after a PFA procedure have been described. Objective To investigate the impact of ablation technology (PFA vs. radiofrequency ablation (RFA)) on the level of plasma cell-free haemoglobin (CFH) and the concentration of serum neutrophil gelatinase-associated lipocalin (NGAL) as a marker of tubular injury. Methods This was a prospective observational trial. In a consecutive cohort of patients who underwent AF ablation (PFA of RFA), blood samples were drawn just before the procedure (Sample 1: CFH and NGAL), immediately after the procedure (Sample 2: CFH) and one day after the procedure (Sample 3: CFH and NGAL). Plasma CHF level and serum NGAL concentration were analysed using the ELISA technique. Results Among 70 patients enrolled (mean age 64.3 ± 10.3 years, 61 % male), 23 underwent RFA and 47 PFA (22 pulmonary vein isolation (PVI) only and 25 PVI with other additive lesions). Baseline serum creatinine levels of both groups were comparable (91.7 ± 22.1 µmol/L vs. 88.8 ± 22.1 µmol/L P = 0.44). In the PFA cohort, a significant peak of CFH concentration was observed just after the procedure with a subsequent decrease within 12 hours (Sample 1 vs. Sample 2: 93.4 ± 65.1 µg/mL vs. 2394.9 ± 1966.1 µg/mL P < 0.001, Sample 1 vs. Sample 3: 93.4 ± 65.1 µg/mL vs. 97.2 ± 68.5 µg/mL P = 0.75). No significant differences were observed in the RFA cohort. Compared to baseline, neither the PFA nor the RFA group showed a significant difference in NGAL levels (PFA 98.6 ± 31.7 ng/mL vs. 98.5 ± 38.1 ng/mL P = 0.78, RFA 108.3 ± 33.8 ng/mL vs. 116.3 ± 32.2 ng/mL P = 0.49). Conclusions Compared to RFA, PFA leads to significant peri-procedural haemolysis. However, no differences in the concentration of the tubular injury marker NGAL were observed on the first day after the procedure.

Impact of conduction velocity in left atrium assessing with omnipolar technology in patients with atrial fibrillation

Abstract Background There is increased interest in exploring substrate of atrial fibrillation (AF) and recent studies have shown that atrial conduction velocity (CV) reflects the electrophysiological phenomena and plays key role in perpetuating AF. The novel omnipolar technology (OT) use three unipolar and two orthogonal bipolar signals allow us to analyze the voltage, activation direction, and CV independent of catheter position. Objective The purpose of the present study was to evaluate if the left atrium (LA) CV which assessed by OT predict the any atrial tachy-arrhythmia (AT) recurrence after initial AF ablation. Methods We enrolled 58 consecutive patients who underwent initial pulmonary vein isolation (PVI) for drug refractory AF. (mean age: 68.2±10.2 years old, 32 male(55.1%), 32 persistent AF(55.1%), CHADS2 score:1.6±0.6). After electrical PVI was achieved and remained in sinus rhythm, the LA was mapped with high density mapping catheter (Advisor HD Grid, Abott USA) utilizing with the novel OT combined with Ensite X system (Abott, USA). The conduction distance and conduction times were measured from the earliest activation site to the latest activation site in LA (Figure 1). Each conduction velocity in anterior, posterior, and septal area were also calculated as conduction distance divided by conduction time. The LA voltage was also measured. Results During a mean follow up period of 316±143 days, the recurrence of AT after initial PVI was observed in 9 (15.5%) patients. There were no significant differences in baseline demographics between AT recurrence and non-recurrence group (mean age:66±13.3 vs 68.5±10.5 years old P=0.66, CHADS2 score: 1.5±0.57 vs 1.68±0.62 P=0.59, proportion of persistent AF: 15.4% vs 15.5% P=0.82, LA volume: 102±35.9 vs 93.6±37.3ml P=0.63). The earliest activation site in LA were identified in 3 areas including anterior site of right pulmonary vein (51.7%), Bachmann bundle area (41.4%), and antero-septal area (6.89%) (Figure 2). In patients with AT recurrence, the CV in LA was significantly slower than those without AF recurrence(0.61±0.21 vs 0.81±0.16 m/s, P=0.036) whereas the whole LA voltage was not (1.52±0.75 vs 2.22±1.06 mv, P=0.28). The CV in each LA portion are similar between recurrence and non-recurrence AT group. (anterior:0.57±0.24 vs 0.81±0.23 m/s, P=0.18, posterior: 0.87±0.18 vs 1.2±0.49 m/s P=0.36, septal: 0.89±0.76 vs 1.15±0.39 m/s, P=0.41). Conclusion The earliest activation site in LA was varied in each case. The whole CV in LA is a predictor of AF recurrence after PVI whereas the CV of each LA portion and LA voltage was not.

Exploring LGE areas in the atria: Insights from electroanatomical voltage mapping in AF patients

Abstract Introduction Late gadolinium enhancement MRI (LGE MRI) is a common method for the evaluation of the atrial substrate in atrial fibrillation (AF) patients. The extent of LGE is associated with atrial cardiomyopathy and ablation outcomes. However, previous studies have yielded inconsistent results in detecting low voltage areas (LVA) using bipolar electroanatomical mapping (EAM) in LGE regions. Objective Conduct a thorough analysis of the bipolar and unipolar voltage in LGE areas and its relationship with the voltage in non-LGE areas, utilizing high-density (HD) EAM generated by a multipolar HD-mapping catheter. Methods In this study, 20 patients undergoing AF ablation were examined using LGE-MRI. A 3D mesh integrating LGE data was generated. HD-EAM (> 4000 points) was performed in sinus rhythm. The EAM map and MRI mesh underwent manual alignment and registration. Using a nearest neighbor algorithm, EAM points nearest to LGE areas were identified, and the corresponding unipolar and bipolar voltage values, along with LGE voxel intensity, were exported for analysis. Results LGE areas exhibited a median bipolar voltage amplitude of 0.93 mV, median unipolar voltage of 1.73 mV. In contrast, areas without enhancement displayed median bipolar voltage of 2.33 mV, unipolar voltage of 3.58 mV. We observed a variation in voltage amplitudes across the different LGE areas: bipolar voltage ranged from 0.04 to 2.51 mV and unipolar voltage from 0.22 to 3.75 mV. This variation strongly correlated with voxel intensity in LGE areas (correlation coefficient r = -0.86 [p <0.001]). Irrespective of the voltage amplitude in the examined LGE areas, a significant voltage drop was observed, with an average reduction of 54% in bipolar and 51% in unipolar voltages, compared to the amplitudes in non-LGE areas within the same atria. Conclusion Variations in bipolar and unipolar voltage within LGE areas are significantly correlated with local voxel intensity. Despite the inconsistent overlap with the predefined bipolar threshold for LVA, LGE regions exhibit a pronounced and consistent reduction in both bipolar and unipolar voltage compared to non-LGE areas. This pattern suggests notable electrophysiological changes in these areas. These insights underscore the need for further investigation to better understand the implications and mechanisms underlying these alterations in LGE regions.

Characterization of sedation strategies in real-world use of pulsed field ablation: sub-analysis of the EU-PORIA registry

Abstract Background/Introduction With the introduction of pulsed field ablation (PFA) to treat patients with atrial fibrillation (AF), there has been interest in studying workflow and sedation strategies to better understand how this new technology can be integrated into clinical practice. Purpose Characterize the use of general anesthesia (GA) versus deep sedation during real-world use of the pentaspline PFA catheter to treat AF. Methods EU-PORIA is an all-comer AF registry enrolling consecutive patients treated with the pentaspline PFA catheter at seven high-volume centers in Europe. Patients were treated based on institutional standard of care. During follow-up, any episode of atrial tachycardia (AT) or AF lasting longer than 30 seconds was considered an arrhythmia recurrence. Results EU-PORIA enrolled 1233 patients, of which 250 ablation cases were performed under GA and 983 cases were performed with deep sedation. Six out of the 7 participating centers employed a single sedation strategy (2 GA; 4 deep sedation), with one center doing a mix of both sedation and GA. The patient population treated with GA had fewer female patients (30% vs 40%; p=0.04), a lower prevalence of hypertension (43% vs 57%; p<0.01), and fewer paroxysmal AF patients (54% vs 62%; p<0.01). The ablation strategy was performed based on operator’s discretion. In the GA group, 72% of patients received a pulmonary vein isolation (PVI)-only ablation approach versus 90% of patients in the sedation group (p<0.01). The most common additional lesion set performed was posterior wall isolation which accounted for 23% and 7% of cases in the GA and sedation groups, respectively (p<0.01). Procedure times and fluoroscopy times were significantly shorter in the sedation group versus the GA group (51 [36-84] min vs 75[60-90] min; 13 [8-19] min vs 19 [15-26] min; p<0.01 for both). Mapping was used in 60% of cases in the GA group versus only 26% of cases in the sedation group. Overall, there were no differences in the incidence of serious adverse events, and no difference in chronic treatment success. At 1-year follow-up, 74.8% of patients (187/250) in the GA group and 73.8% of patients (725/983) in the sedation group were free from recurrent AF/AT. Conclusion(s) In this registry, the use of deep sedation for AF ablation with the pentaspline PFA catheter demonstrated a safety and efficacy profile consistent with those procedures performed under GA. The majority of the deep sedation procedures were PVI-only and performed in a less progressed AF disease state. It is worth noting that there may be certain patient populations and center restrictions where GA will remain the necessary approach for AF ablation. This characterization of real-world use warrants further evaluation to understand optimal sedation strategies that can be used with PFA technologies.

Prevalance of incessant form of atrial fibrillation by superior vena cava (svc) firing:simplified svc and sinus node mapping(sss map) to avoid sinus node injury

Abstract Background The superior vena cava (SVC) is known as a major source of atrial fibrillation(AF), non-pulmonary vein AF foci (NPVAF). In some cases, an incessant form of AF (iAF) by SVC firing prevents obtaining the sinus node location, and anatomical SVC isolation has a risk of sinus node injury (SNI). Objective This study was aimed to explore the frequency of iAF by SVC firing and the efficacy of the simplified mapping strategy to avoid SNI. Methods Consecutive AF ablation procedures in the 3 centers were retrospectively investigated including the NPVAF prevalence. Simplified SVC/SN mapping (SSS-map: Obtaining the top-end of the SVC potential and >4points with 5-10mm spacing in the upper lateral side of the right atria (RA) for roughly locating the earliest activation site in sinus rhythm) was performed before PV isolation in the last 138 patients. In case of the initial rhythm at the procedure was atrial fibrillation, cardioversion was performed for obtaining the SSS-map. In the cases in which the high-density mapping catheters were available, the high-density activation maps of the RA in sinus rhythm were obtained to investigate the dislocation of the earliest activation site of the SSS map from the SN location. When SVC isolation was required due to iAF, SVC isolation line was designed based on the location of the top-end of the SVC potential during AF and ablative linear lesions were created to keep the distance of 5-10 mm above the second earliest activation site. Results A total of 1160 procedures in 1089 patients (male: 736[63.4%], age: 69.9, paroxysmal AF: 544[49.9%], first session: 997[85.9%]) was investigated. Prevalence of NPVAF was revealed in 160 of the all procedures (13.7%) (the SVC: 64, the posterior wall of the left atria: 24, the coronary sinus: 19, and others: 53). 16 of 160 NPVAFs (10.0%) developed to iAF by SVC firing. The SSS-map was successfully obtained in all of the last 138 patients (Initial rhythm at the procedure: AF 43.7%, Mapping time: 1.3±0.6 min, number of obtained points: 8.4±1.3). In 21 patients in which the high-density RA map was obtained, the SN dislocation distance was 5.1±2.2mm between the SSS map and the high-density RA map. Five of 138 developed to iAF by SVC firing, and SVC isolation based on the SSS-map was successfully achieved without SNI in the cases. Conclusion This study indicated iAF driven by SVC firing after PV isolation occurred in certain number of patients. The SSS-map before PV isolation was practical and showed the potential to be the mapping strategy avoid the SN injury in such cases.

Unipolar electroanatomical mapping outperforms bipolar voltage in detecting LGE areas in the left atrium

Abstract Introduction In atrial fibrillation (AF) management, understanding left atrial substrate is crucial. While both electroanatomical mapping (EAM) and late gadolinium enhancement MRI (LGE MRI) are reliable methods in assessing atrial substrate and are associated with the ablation outcome, recent findings have highlighted significant discrepancies between bipolar low voltage areas (LVA) in EAM and LGE areas. Objective Explore the relationship between LGE areas and unipolar LVAs by utilizing multipolar high-density (HD) mapping. Methods Nineteen patients scheduled for AF ablation underwent pre-ablation LGE-MRI. Left atrial (LA) segmentation was conducted using a convolutional neural network, which subsequently generated a 3D mesh integrating the LGE data. HD-EAM was performed in sinus rhythm for each patient, capturing at least 4000 points. The EAM map and LGE MRI mesh were co-registered. LVA areas were defined using voltage cut-offs of 0.5 mV for bipolar and 2.5 mV for unipolar measurements. Correspondence between LGE areas and LVAs on the anterior and posterior LA wall was analyzed. Results Both bipolar and unipolar LVA demonstrated high precision in detecting LGE areas (100% and 88% respectively). However, unipolar LVA exhibited a remarkable accuracy of 81% for detecting LGE areas specifically, whereas bipolar LVA displayed a significantly lower accuracy of 28%. These findings were consistent across the different atrial walls. Conclusion Incorporating unipolar voltage data into electroanatomical mapping in the atrium may bridge the observed gap between LGE areas and bipolar LVAs. Our findings highlight the significance of unipolar voltage in evaluating the left atrial substrate, potentially offering a more comprehensive insight into the different layers of atrial walls, and opening the door for new approaches in AF therapy.

Pulsed field ablation using additional mapping and substrate modification to treat atrial fibrillation - one year outcome comparison

Abstract Background Pulsed field ablation (PFA) is a relatively new non-thermal form of ablation employing irreversible cell electroporation as an alternative to radio-frequency ablation. Conventional use of PFA relies on fluoroscopy. Electro-anatomical and voltages mapping (EAM) may potentially provide refinement of PFA via ablation of non-PV targets and accurate localisation of catheter placement. Currently there is limited data on the efficacy of the use of voltages criteria of EAM in conjunction PFA in the treatment of atrial fibrillation. Objective The aim of our study was to determine the effect on atrial arrhythmia recurrence with the use of EAM with PFA in patients requiring atrial fibrillation ablation. Methods This single centre retrospective observational analysis included one hundred patients with symptomatic AF (paroxysmal and persistent) undergoing ablation for the first time. Fifty patients underwent PFA-PVI alone and fifty patients underwent PFA-PVI with EAM. Data were obtained on patient characteristics, outcomes, procedure details and complications up to one year. A blanking period of three months was used post-ablation. For rhythm monitoring we utilised ECGs and holters at three, six, nine and twelve months and twenty-four hour holter monitoring at six and nine months. We also used remote monitoring in between these periods to record any symptomatic episodes atrial arrhythmias. Results Baseline patient characteristics are represented in Table 1. Despite having no significant difference in category of AF between groups (Paroxysmal, persistent, longstanding persistent) the mapping group were significantly older (68.2 years ± 10.2 vs 60.1 ± 11.11; p=0.01), longer duration of documented atrial fibrillation (45.9 ± 50 vs 28.6 ± 38 months; p=0.038), higher risk for CV events with CHA2DS2-VASc score (2.2 ± 1.5 vs 1.42 ± 1.2; p=0.04), however, procedure times were greater in the PVI and mapping group (72.8 ± 6.2 vs 41.1 ± 17 minutes; p=0.03). Successful PVI was achieved acutely in all patients upon voltage guided mapping validation and most importantly 1 year follow up revealed comparable outcome in both groups (Fig 1). Conclusion Patients who underwent PFA with mapping were older, greater co-morbidity and longer duration of AF burden. Yet, the addition of EAM with PFA did demonstrate equivalent achievement of sinus rhythm and was relatively high as higher than 80 % at one year follow up. This study may suggest a preference to using EAM in patients who may be deemed to be older and have a greater co-morbidity. It emerges as a great hope to safer approach and successful intervention to reduce AF burden.mapping vs PVI onlyGraph showing one year follow up