Additional Substrate Modification Research Articles

Predicting atrial fibrillation ablation success: a novel approach using pre-procedure sinus rhythm ecg and deep learning

Abstract Introduction Pulmonary vein isolation (PVI) has been the corner stone of the treatment of patients with atrial fibrillation (AF), yet its efficacy varies notably between patient groups. Specifically, it shows reduced efficacy in individuals with persistent AF and those with atrial fibrosis. Recent advancements suggest that additional substrate modification could enhance outcomes in specific patient groups. Therefore, predicting the outcomes of lone PVI could help in stratifying patients who would benefit most from this additional substrate modification. Addressing this gap, our study explores the prognostication of PVI outcomes using pre-procedural 12-lead ECG recordings taken in Sinus rhythm, employing advanced deep learning techniques. Methods This retrospective study analyzed 209 patients with paroxysmal and persistent AF who underwent PVI. These patients were followed up for 12 months after the blanking period. Pre-procedural sinus rhythm 12-lead ECGs were processed using an innovative deep learning architecture, integrating Long Short-Term Memory and Convolutional Neural Networks with a cross-attention module. This multimodal deep learning model was trained using ECG and clinical covariates like age, sex, and BMI to predict binary outcomes – AF type (Paroxysmal or Persistent) and AF recurrence. The model's efficacy was evaluated through a 5-fold stratified cross-validation to ensure accuracy and reliability. Model was also tested using only ECG data. Results The multimodal deep learning model performed significantly better as compared to the model trained using ECG data only. The multimodal deep learning model achieved an accuracy of 75.56% and a sensitivity of 82% in prognosticating ablation outcomes. Additionally, the model demonstrated a significant capability in classifying AF into paroxysmal or persistent types with an accuracy of 86.67% and a recall of 89%. Conclusion Our deep learning approach in analyzing sinus rhythm ECG recordings shows promising results in predicting PVI outcomes and identifying AF types. This approach could offer a more accessible and cost-effective tool to stratify AF patients undergoing PVI, identifying those less likely to benefit from standard procedures. Such insights can assist physicians and patients in determining ablation candidacy and selecting the most appropriate ablation strategy and technique.Proposed StrategyDeep learning model approach

Comparative analysis of clinical outcomes in repeat ablation for recurrent atrial tachyarrhythmia following initial pulmonary vein isolation with pulsed-field ablation and cryoballoon ablation

Abstract Background While pulsed-field ablation (PFA) holds promise for the initial catheter ablation performing pulmonary vein (PV) isolation (PVI) in patients with atrial fibrillation (AF), a repeat procedure remains necessary for those experiencing recurrent atrial tachyarrhythmia (ATA). This study aimed to evaluate the clinical outcomes of repeat procedures following the initial PFA in patients with recurrent ATA by comparing that following the initial CBA. Methods Patients who underwent a second ablation for recurrent ATA following initial PVI with pentaspline PFA or cryoballoon ablation (CBA) were included. Repeat ablation utilized radiofrequency current ablation with three-dimensional mapping guidance, involving repeat PVI combined with linear ablations when necessary. Acute data, such as documented arrhythmia before the repeat procedure, the number of reconnected PVs, procedural characteristics, and clinical follow-up, were analyzed. Results In total, 110 patients underwent initially successful PVI with PFA (N = 51) and CBA (N = 59), followed by a repeat procedure for recurrent ATA with a mean time interval of 365±299 days between the two procedures. The primary indication at the repeat procedure was atrial tachycardia (AT) in the PFA group (N = 27, 53%) and AF in the CBA group (N = 47, 80%). The overall PV reconnection rate per vein was 22.1%, with no significant difference between the two groups (19.1% in PFA vs. 24.7% in CBA, P = 0.16). Repeat PVI was successfully performed in all patients with PV reconnection (41.2% in PFA vs. 55.9% in CBA, P = 0.12). PV reconnection was most commonly found at the right inferior PV in both groups (25.5% vs. CBA; 32.2%, P = 0.44). Additional substrate modification was conducted in 76.5% of the PFA group and 74.6% in the CBA group, respectively (P = 0.82). The mean follow-up period was 349±280 days. The Kaplan-Meier curve indicated no statistical significance in the 1-year arrhythmia-free survival after the repeat procedure (62.4% in PFA vs. and 73.0% in CBA group, P = 0.54, Figure). Conclusion Comparable lesion durability between the initial PVI with PFA and CBA was unveiled during the repeat ablation. The second ablation for recurrent arrhythmia following initial PFA demonstrated a favorable clinical success rate at one year after the subsequent procedure, showing no significant difference compared to repeat ablation subsequent to CBA.arrhythmia-free survival after the repe

Durability of pulmonary vein isolation after radiofrequency-balloon ablation

Abstract Aims Recently a multi-electrode radiofrequency balloon (RFB) for pulmonary vein isolation (PVI) was introduced. To the best of our knowledge no data on PVI durability has yet been published. Objectives The aim of this single-center study was to investigate the incidence of pulmonary vein (PV) reconnectionafter RFB-guided PVI. Methods Patients undergoing second ablation for recurrent atrial tachyarrhythmia (ATa) following the initial RFB-PVI were investigated. Left arial (LA) electroanatomic mapping was used. The rate of PV reconnection, the type of recurrent ATaand procedural data were analyzed. Results Among 178 patients treated with RFB, 21 patients underwent a second procedure 11 ± 6 months after the initial PVI. 67% of these patients presented with atrial fibrillation (AF), 33% with atrial tachycardia. Regarding baseline characteristics, 71% of these patients were male, mean age was 67±10, mean BMI was 28±5, 67% had hypertension and 33% had coronary artery disease. Overall, 83 PVs including one left common PV (LCPV) were assessed. The rate of PV reconnection was 28% (23/83 PVs). 57% of patients (12/21) had at least one reconnected PV. Patient with PV-reconnection had more AF recurrence and less often atrial tachycardia (AT) (AF: 75%, AT: 25%) than patients with durably isolated PVs (AF: 56%, AT: 44%). Most reconnections were detected in septal PVs. Reconnections were distributed as follows: RIPV: 8/21, RSPV: 7/21, LIPV: 5/20, LSVP: 3/20, LCPV: 0/1. Precise localization of the gaps could be identified in 15/23 PVs. Most common gap locations were at the anterior carina (4/15) for septal PVs and anterior-inferior (3/15) at the LIPV. Ablation strategy was pure PV reisolation in 8/12 patients and PV reisolation with additional linear lesions in 4/12 patients. All patients with durably isolated PVs were treated with additional substrate modification. In total, following additional lesions were set: anterior line: 6, roof line: 11, cavotricuspid isthmus (CTI): 7, LAA-Isolation: 1, free wall of the right atrium: 1. Regarding procedural data of the index procedure, the number of applications was not a statistically significant predictor of reconnection (p=0.77). Conclusion We provide the first insight into durability of PVI after radiofrequency-balloon ablation. 72% of all PVs were still isolated. Our data on gap localization might help to identify regions where optimal balloon contact is difficult to achieve. More data on this topic might reveal predictors for PV reconnections.

Pulsed electric field ablation for perimitral flutter - retrospective comparison of anterior vs lateral mitral block strategy

Abstract Introduction Catheter ablation of atrial fibrillation has become a standard of care for symptomatic patients. Patients with persistent atrial fibrillation might require additional substrate modification on top of pulmonary vein isolation. In case of spontaneous or inducible perimitral flutter, RF ablation to achieve anterior or lateral mitral block is challenging. A pulsed electric field (PEF) is a novel energy source that enables the rapid and safe creation of larger lesions. Purpose A retrospective study aimed to compare the safety and early outcome data of either anterior or lateral mitral block strategy performed by PEF using a pentaspline multipolar ablation catheter. Methods The population consists of 67 patients (23 women, age: 68 ± 8 years) with either spontaneous or inducible perimitral flutter. Fifty-five percent of patients had previous ablation of atrial fibrillation using radiofrequency energy (2.0 ± 1.2 procedures/patient). Using a pentaspline multipolar catheter, all patients underwent isolation (or reisolation) of pulmonary veins and posterior wall. The same catheter was used for the treatment of perimitral flutter. Creating either anterior (ANTERIOR group) or lateral (LATERAL group) mitral block was selected at the discretion of the operator. Results A total of 37 and 30 patients were treated in the ANTERIOR and LATERAL groups, respectively. The perimitral flutter was terminated in all cases. However, complete and persistent block across the ablated region was more likely achieved in the ANTERIOR vs LATERAL group (92 vs 73%, p=0.04). There was one tamponade in the ANTERIOR group. A clinically relevant spasm of the coronary artery was not observed in any patient. At 3-month follow-up, non-significantly more patients were in sinus rhythm in the ANTERIOR vs LATERAL group (81% vs 63%, p=0.1). Conclusion Creating both anterior and lateral mitral block for the treatment of perimitral flutter is feasible and safe using a pentaspline multipolar catheter and PEF. Achievement of the anterior mitral block is more likely. Whether this will impact the long-term outcome remains to be determined.

Abstract 15076: Long-Term Recurrence Free Survival in Second Generation Cryoballoon Ablation for Persistent Atrial Fibrillation: It’s All About the Autonomic Nervous System

Introduction: Cryoballon (CB)-guided pulmonary vein isolation (PVI) is an accepted treatment option for atrial fibrillation (AF). The cardiac autonomic nervous system (ANS) plays a crucial role in the regulation of AF. Hypothesis: ANS modulation has an impact on patients’ AF free survival following CB-ablation. The aim of this observational clinical trial was to analyze the impact of vagal reactions (VRs), as a surrogate parameter for ANS modulation, on the long-term outcome of CB-ablation in patients with persistent AF (PERS AF). Methods: Data from consecutive PERS AF patients treated with a CB-guided PVI for symptomatic drug refractory AF between 2013-2023 were analyzed. VRs were defined as bradycardia < 40 beats/min, asystole or higher-degree atrioventricular block. All patients were continuously followed up in our outpatient clinic. AF-recurrence was defined as AF lasting > 30 seconds beyond a 3-month blanking period. Results: A total of 250 consecutive patients (mean age 63.9 ± 10.0 years, 70% male) were included. VRs were recorded in 61 patients (24%). The mean follow-up duration amounted to 84±14 months. Within this observation period 101 patients (40%) developed AF recurrence a mean of 1.75 ± 0.80 times. Re-ablation procedures were performed in 61 patients (60%) a mean of 1.28 ± 0.55 times. Reconnected PVs were documented in 41 cases (67%). An additional substrate modification was performed in 34 procedures (42%). Patients with procedure associated VRs presented with a significantly higher estimated AF-free survival rate compared to those without (log-rank p-value=0.016) (Figure1). Multivariate analyses revealed the days to first AF recurrence following primary CB-ablation as an independent predictor for AF-free survival (CI 0.841-0.928, HR, 0.883, p<0.01). Conclusions: CB-ablation procedure associated VRs seem to be associated with a favorable long-term outcome in PERS AF. Thus, our findings may influence future CB-ablation strategies.

Incremental value of low-voltage area ablation in persistent atrial fibrillation: a systematic review and meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction The optimal ablation approach for patients with persistent atrial fibrillation (AF) is a topic of high controversy. The efficacy of adjunctive ablation strategy beyond conventional pulmonary vein isolation remains uncertain. Purpose We sought to investigate the effectiveness of individualized low-voltage area (LVA) substrate modification in patients with persistent AF receiving conventional catheter ablation. Methods We systematically searched PubMed, Cochrane Library, and grey literature sources including clinicaltrials.gov, from inception to 1st November 2022, to identify relevant randomized controlled trials (RCTs). Patients with persistent AF undergoing conventional catheter ablation vs. ablation with additional LVA substrate modification were compared. Freedom from arrhythmia was set as the primary efficacy outcome and total procedure time as the secondary efficacy outcome. A prespecified subgroup analysis was performed for patients with presence of LVAs. We did not impose any filter regarding the study setting, sample size, study duration, or publication language. All analyses were performed using R version 4.1.0 and a two-sided p-value<0.05 was considered statistically significant. Results We pooled data from 5 RCTs with a total of 989 participants (31% female) with persistent AF. Ablation with additional LVA substrate modification resulted in a significantly increased likelihood for freedom from arrhythmia by 60%, compared to conventional AF ablation (odds ratio 1.60; 95% confidence interval 1.13-2.28; I2=39%; p=0.009). No difference in the total procedure time was identified between the two approaches (mean difference -28.94 min; 95% confidence interval -69.39 to 11.51 min; I2 = 98%, p=0.16). In patients with LVAs (n=240), additional LVA substrate modification yielded a higher probability for freedom from arrhythmia than conventional AF ablation (odds ratio 1.73; 95% confidence interval 1.03-2.90; I2=0%; p=0.04). Conclusion This meta-analysis demonstrates that an individualized ablation approach with low-voltage area substrate modification is associated with improved outcomes in patients with persistent AF.

AB-452665-4 ATRIAL SCAR: GENDER DIFFERENCE IN PREVALENCE AND PROGNOSIS OF ADDITIONAL SUBSTRATE MODIFICATION IN PATIENTS WITH ATRIAL FIBRILLATION RESULTS FROM STABLE-SR-III TRIAL

Female gender has long been recognized to present a higher burden of low-voltage area (LVA), and tend to have an increased atrial fibrillation (AF) recurrence rate than male after circumferential pulmonary vein isolation (CPVI). However, benefits of additional LVA modification in female patients with AF remain unknown. This study was to describe the prevalence of LVA and outcomes of additional substrate modification according to sex at entry STABLE-SR-III trial. Patients aged 65-80 years were randomly assigned to either CPVI plus LVA modification during sinus rhythm (STABLE-SR) group or “golden-standard” CPVI alone group. The primary outcome was freedom from atrial arrhythmias lasting for ≥30 s after a single ablation procedure. Of 414 patients included in the STABLE-SR-III, 204 (49.3%) were female, mean age was 70.5±4.7 years. Females demonstrated significant higher LVA prevalence (51.5% vs. 32.9%, P=0.000) and burden [6.5% (2.7-12.4) vs. 2.9% (1.9-5.9), P=0.000] than males. Female sex, age and large left atrial diameter were independent predictors of LVA. For the primary outcome, additional LVA ablation was associated with a 65% reduction in atrial arrhythmias recurrence for females (hazard ratio 0.35; 95% CI 0.19-0.65, P=0.002). Females with LVA who received CPVI alone had significantly higher recurrence rate than those females without LVA and those females with LVA receiving substrate modification (P=0.003). Female sex was found to have a higher LVA prevalence, LVA burden, and greater benefit of additional LVA modification than male. Addictive LVA ablation has emerged as a promising solution to improve the success rate in this population.

Effect of gender on atrial fibrillation ablation outcomes using a propensity score-matched analysis.

Previous studies have shown that women with atrial fibrillation (AF) have a higher incidence of recurrence and non-pulmonary vein (non-PV) triggers. However, there remains an incomplete understanding of the impact of gender on AF ablation strategies and outcomes. The purpose of this study was to evaluate the impact of gender on AF ablation outcomes. We analyzed 1568 AF ablations in 1412 patients (34% female) performed at a single tertiary care center between January 2013 and July 2021. Patients were followed for at least 6 months (mean 34 months) for detection of AF recurrence, complications, and emergency department visits/hospitalizations. The effect was assessed by multivariate logistic regression analysis using propensity score matching (PSM). Mean age was 64 years, and mean body mass index (BMI) was 31 kg/m2. Seventy-seven percent of patients underwent de novo ablations. Twenty-seven percent of patients had persistent AF, with a recurrence rate of 37%. There was no difference in AF recurrence when stratified by gender (hazard ratio [HR] 1.15; 95% confidence interval [CI] 0.92-1.43; P >.05) and age. After PSM gender 1:1 (criteria: age, type of AF, hypertension, diabetes mellitus, and BMI; n = 888 patients), there was no difference in AF recurrence or procedure-related complications. Having a history of persistent AF (HR 1.54; 95% CI 1.18-1.99; P = .001) predisposed to recurrence of AF. Persistent AF (HR 2.99; 95% CI 1.94-4.78; P <.001) and age >70 years (HR 1.03; 95% CI 1.02-1.05; P <.001) were associated with the need for additional substrate modification with no difference based on gender. There was no difference in overall safety or efficacy outcomes between genders after AF ablation.

Abstract 14153: The Effect of Gender on Atrial Fibrillation Ablation Outcomes Using a Propensity Score Matched Analysis

Introduction: Previous studies have shown that woman with atrial fibrillation (AF) have increased non-pulmonary vein (PV) triggers which requires additional substrate modification during AF ablation. However, there remains an incomplete understanding of the impact of gender on AF ablation strategies and outcomes. Methods: At a single tertiary care center between January 2013 and July 2021, we analyzed 1576 AF ablations in 1412 patients, of whom 33% were female. Patients were followed for at least 6 months (mean 34 months) to detect AF recurrence, complications, and emergency room visits/hospitalizations. The effects of gender on AF clinical characteristics, AF recurrence, procedural approach and complications were assessed by multivariate logistic regression analysis using propensity score matching. Results: Of 1412 patients, mean age was 64 and mean BMI was 31 kg/m2. 77% underwent de novo ablations, and 27% patients had persistent AF at the time of ablation. The overall rate of AF recurrence was 37%. There was no difference in AF recurrence when stratified by gender (HR 1.15; CI: 0.92-1.43, p &gt;0.05) and age (Fig. 1A &amp; 1B). After propensity score matching gender 1:1 (criteria: age, type of AF, HTN, DM, and BMI, n = 888 patients), there was no difference in AF recurrence (Fig. 1C) or procedure related complications. Additional substrate modification was associated with persistent AF (OR 2.99; CI: 1.9-4.69, p &lt;0.05) or age greater than 70 years (OR 1.03; CI: 1.02-1.05, p &lt;0.05) with no difference based on gender. During ablation, first pass PV isolation was more likely achieved in males (OR 0.7; CI: 0.53-0.93, p &lt;0.05) and patients with BMI &lt; 30 kg/m2. There was no significant difference in the rate of PV reconnection during redo ablations between genders (OR 1.05; CI: 0.71-1.55, p &gt;0.05). Conclusions: Despite a lower rate of first-pass PV isolation in female patients, there is no difference in overall safety or efficacy outcomes between genders following AF ablation.

Outcomes of additional substrate modification in de novo atrial fibrillation ablation

Abstract Background Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Data regarding additional substrate modification has been conflicting, both in paroxysmal and persistent atrial fibrillation. Purpose To assess the effect of additional linear substrate modification during de novo AF ablation on AF recurrence. Methods We reviewed 1575 AF ablations in 1254 patients from January 2013 to June 2021 at a single academic medical center. There were 1096 de novo ablations. We defined substrate modification as linear ablations including cavotricuspid isthmus (CTI), superior vena cava isolation, intercaval line, mitral isthmus, and left atrial roof and floor lines. We evaluated clinical and procedural characteristics to identify risk factors for AF recurrence and complications. Patients were followed for a minimum of 6 months. Results The 1096 de novo ablations included 65.5% males with mean age 61.1 years, mean BMI 31.3, 81.8% paroxysmal AF and 18.2% persistent AF. There were four AF ablation subgroups: PVI alone (41.6%), PVI and CTI ablation (37.1%), PVI with CTI and additional substrate modification (15.6%), and PVI with substrate modification without CTI ablation (5.7%). Overall, AF recurred in 36.9% cases. AF recurrence with PVI only ablation was 41% compared to 32.7% in patients with PVI and CTI ablation (p=0.02). When looking at patients with paroxysmal and persistent AF, results were similar, with decreased AF recurrence with the addition of CTI ablation in both paroxysmal (37.3% v. 29.2%, p=0.03) and persistent AF (58.1% v. 40.0%, p=0.02). Additional substrate modification did not result in significant difference in outcome in either paroxysmal or persistent AF (Figure 1). Conclusions In de novo AF ablations, addition of CTI ablation to de novo PVI ablation is associated with lower AF recurrence in both paroxysmal and persistent AF. Additional linear substrate modification did not impact outcomes. Funding Acknowledgement Type of funding sources: None.

Low voltage area as a predictor of recurrence after a single pulmonary vein isolation procedure: results of the WAVE-MAP AF study

Abstract Background/Introduction Pulmonary vein isolation (PVI) is a recommended approach for atrial fibrillation (AF) ablation procedures. Substrate modification beyond PVI has mixed results but identifying and ablating low voltage zones and ablating those targets in addition to PVI may be beneficial. Electroanatomic mapping is critical to identify subjects that may require further substrate modification. Low voltage area may be predictive of optimal treatment approach. Purpose This was a prospective, multicenter, interventional study of a high-density grid-style mapping catheter (HD Grid) to characterize left atrial low voltage substrate during sinus rhythm (SR) and AF and identify associations with 12 month recurrence rates after a single de novo radiofrequency (RF) ablation using a PVI only approach. Methods This study (NCT03882021) enrolled 300 subjects at 18 centers in Europe and Israel. Subjects underwent de novo RF ablation for paroxysmal AF (PAF) (N=113), early persistent AF (PsAF; AF sustained 7 days to 3 months) (N=86) or non-early PsAF (AF sustained &amp;gt;3 months to 12 months) (N=101). High density voltage maps were collected with HD Grid. Two pre-ablation maps, in SR and AF, were created for each subject (N=196) followed by PVI only ablation. Low voltage area (using cutoffs of 0.1 mV to 1.5 mV) was investigated in SR and AF. Follow up visits were at 3, 6 and 12 months post-ablation, with a 24-hour Holter monitor at 12 months. A Cox proportional hazards model was used to identify associations between mapping data and 12 month AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence after a single PVI procedure. Results At 12 months, 75.5% of subjects were free from AF/AFL/AT recurrence. On average, PsAF subjects had more low voltage area than PAF subjects in SR and AF. However, while univariate analysis found no correlation between recurrence and PAF or PsAF diagnosis (p=0.1261), those with recurrence had a significantly larger percent left atrial low voltage area under 0.5 mV with simultaneous orthogonal bipole wave configuration (HDW) in both AF (p=0.0011) and SR (p=0.0210) than those without recurrence. Using HDW, low voltage area (identified as &amp;lt;0.5 mV) greater than 28% of the left atrium in SR (HR: 4.82, 95% CI: 2.08–11.18, p=0.0003) and greater than 72% in AF (HR: 5.66, 95% CI: 2.34–13.69, p=0.0001) were associated with a higher risk of AF/AFL/AT recurrence at one year. Conclusion(s) Using a standard cutoff of 0.5 mV, a larger percent low voltage area was associated with increased risk of recurrence in both SR and AF. Future analyses will explore optimal low voltage cutoffs and thresholds predictive of recurrence that may necessitate additional substrate modification beyond PVI. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Abbott

Empirical superior vena cava isolation in patients undergoing repeat catheter ablation procedure after recurrence of atrial fibrillation.

Although the ectopic foci responsible for initiating atrial fibrillation (AF) are usually located in the pulmonary veins (PVs), non-PV sources may initiate AF in approximately 11% of unselected patients with paroxysmal or persistent AF. The superior vena cava (SVC) is one of the most frequent non-PV origins for initiating AF. This study aims to investigate the effect of empirical SVC isolation in redo AF ablation procedures. Consecutive patients undergoing redo AF ablation procedures using a high-power short-duration protocol (HPSD) (50W; ablation index guided; target AI 350 for posterior wall ablation, AI 450 for anterior wall ablation; CARTO 3 mapping system) were included. Patients with SVC isolation were compared to patients without SVC isolation. Periprocedural parameters and complications were recorded and analyzed. Short-term endpoints included intrahospital AF recurrence, midterm endpoint AF freedom after 3months, and long-term endpoint AF freedom after 12months. A total of 276 patients underwent repeat ablation for recurrent AF (67 ± 10years; 57% male; 31.5% paroxysmal AF). The patients were divided into two groups: redo procedures with SVC isolation vs redo procedure without SVC isolation. Additional LA substrate modification was done based on intraprocedural voltage maps. Baseline characteristics did not differ significantly between the two groups. Median procedure time was 85.4 ± 27.1min with ablation times of 14.0 ± 8.5min. Intrahospital AF recurrence occurred in 32 patients (12%) with no difference among both groups: 17 patients (13%) SVC vs 15 patients (10%) No-SVC; p = 0.416. At 3-month follow-up, 47 (17%) presented an AF recurrence during the blanking period: 25 patients (19%) SVC vs 22 patients (15%) No-SVC; p = 0.304). After 12months, 202 (73%) of all patients were in stable sinus rhythm with no significant difference between the two groups: 93 patients (73%) SVC vs 109 patients (74%) No-SVC; p = 0.853). No significant differences were noted when dividing the patients in paroxysmal or persistent AF with and without SVC isolation. In our series of repeat AF ablation procedures, the addition of empirical SVC isolation to Re-PVI and LA substrate modification did not influence AF recurrence rates. This strategy can however be safe and useful in patients in whom SVC is identified as a trigger of AF.

Validation of seven risk scores in a prospective and independent cohort: the challenge of predicting recurrence after atrial fibrillation ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Several predictive scores for atrial fibrillation (AF) recurrence after ablation have been developed, only some of these are validated in prospective cohorts. The predictive value of such scores has thus far been limited, and many have not been compared with one another. Aims We sought to compare the predictive value of seven previously described risk scores ((CHA2DS2 and CHA2DS2-VASC, HATCH, APPLE, CAAP-AF, BASE-AF2, MB-LATER) for prediction of AF recurrence risk at 12 months after AF ablation. Further, we aimed to identify additional variables to predict recurrences after AF ablation. Methods We analyzed data from of our prospective digital AF ablation registry to compare the previously published scores in an independent and prospective cohort (n=883, 50.8% with paroxysmal AF). Patients were undergoing de-novo ablation of AF received a pulmonary vein isolation (PVI) using radiofrequency (RF) ablation or cryoablation. Ablation procedures for recurrences of AF after initial PVI included re-isolation of the pulmonary veins by RF ablation, with additional substrate modification at the operators’ discretion. Early recurrence and recurrence after ablation were defined as any AF or atrial tachycardia episode lasting ≥ 30 s in the first 3 months after ablation and from the end of the 3-month period to 12 months after ablation. Follow-up of patients was scheduled at regular intervals 3 and 12 months after ablation, and included Holter-ECG, 12-lead ECG and history. Outcome-relevant data from implanted cardiac devices (CIED), such as 2-chamber ICD and pacemakers, or implantable loop recorders were analyzed when available. A predefined subgroup analysis was performed in the following subgroups: first procedure vs. redo procedure, paroxysmal vs. persistent AF, and RF ablation vs. cryoablation. Results The BASE-AF2 (AUC 0.630, p&amp;lt;0.001), MB-LATER (AUC 0.612, p&amp;lt;0.001) CAAP-AF (AUC 0.591, p&amp;lt;0.001), APPLE (AUC 0.591, p&amp;lt;0.001) and CHA2DS2-VASC (AUC 0.547, p=0.018) scores had a significant but modest predictive value for 12-month AF-recurrence. None of these scores was significantly superior. Other previously published scores had no predictive value. There was no difference in the predictive value for 12-month recurrence of AF between first procedure vs. redo procedure and RF ablation vs. cryoablation. Unlike other scores, MB-LATER showed better predictive value for paroxysmal vs. persistent AF (AUC 0.632 vs. 0.551, p=0.038). In the multivariate logistic regression, only age (p=0.006), number of prior electrical cardioversions (p&amp;lt;0.001) and early AF recurrence (p&amp;lt;0.001) were independent predictors of 12-month AF recurrence. Conclusion Despite numerous available scores, predicting recurrences after AF ablation remains challenging. New simple and robust predictors are needed, potentially based on diagnostic interventions, as well as novel genetic, functional and anatomic parameters.

Why are redo AF ablations required and what does it take? Type of index PVI predicts pattern of redo ablations

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation targeting isolation of the pulmonary veins (PVI) is the most effective treatment for atrial fibrillation (AF). Despite its high overall effectiveness, repeat AF ablations (re-do procedures, RDP) are often required to maintain sinus rhythm. Purpose Determine predictors for multiple and/or complex RDP, evaluate reference values for procedure duration and radiation exposure during index PVI (iPVI) and nth RDP in a large cohort. Methods and Results Data mining identified 934 (mean age 62.6 ± 12.3 years, 346 females) out of 6848 total AF ablation patients from a large German AF ablation center between 09/2008 and 09/2021 with an index PVI and at least one RDP. Analysis included 2152 procedures (out of 8750 total AF-related ablations). At iPVI, AF pattern was classified as paroxysmal AF (PAF) in 387 patients (41%). All others (59%) were classified as non-paroxysmal AF (Non-PAF). Non-PAF was significantly more frequent in males (64% vs. 49%, p&amp;lt;0.01). Median period between first PVI and RDP was 558 days (25th/75th percentiles 244.0/1175.5 days). Non-PAF patients had a significantly higher probability of multiple RDP compared to patients with PAF at iPVI (p&amp;lt;0.01, Figure 1A). 18% (8%) of patients with non-PAF had 2 (3) or more RDP while only 13% (3%) of pat. with PAF had 2 (3) or more RDP. iPVI was classified as PVI-only or PVI with additional substrate modification (SM). 724/934 patients (78%) received PVI-only as initial procedure. Of these, 572 (79%) had only 1 RDP, 116 (16%) had 2 RDP and 36 (5%) had 3 or more RDP. This distribution was 77%, 15% and 8% for 1, 2 and 3 or more RDP for patients with complex PVI as iPVI. An algorithm based on regular expressions classified all RDP as repeat PVI (Re-PVI) due to reconduction (PV reconduction), ablation of atrial tachycardia (AT) or SM, e. g. defragmentation of fractionated signals, or combinations. The results were manually quality-controlled. 798/934 (85%) patients required PV re-isolation due to PV reconduction, 298/934 (32%) required ablation for atrial tachycardia (AT) at least once during FU (Figure 1B). Comparing PVI-only iPVI patients with patients who received substrate modification during iPVI, significantly less patients with PVI-only iPVI had RDP for AT compared to those with SM during iPVI (27% vs. 50%, p&amp;lt;0.01). More PVI-only iPVI patients required PV-reisolation at any time during FU (87% vs 79%, p&amp;lt;0.01). Considering PVI-only (+/- CTI) iPVIs only, dose-area product decreased in RDP compared to first PVI, while procedure duration slightly increased (Figure 1C). Data on periprocedural complications will be reported. Conclusion Redo AF ablations procedures are mainly required due to reconnected pulmonary veins or AT. Patients with PAF at iPVI are less likely to require more than one RDP which provides indirect support for early rhythm control in treatment of AF. SM at iPVI might be a predictor for occurrence of AT in the further course.

Clinical outcomes in patients with persistent atrial fibrillation after technologic advances including contact force-guided and ablation index-guided ablation

PurposeWe aimed to evaluate the influence of technological advances on ablation outcomes in patients with persistent atrial fibrillation (AF) (PeAF). Radiofrequency ablation for patients with AF has advanced, including contact force (CF)-sensing catheters and the ablation index (AI).MethodsBetween 2009 and 2018, we analyzed 173 patients with PeAF who underwent catheter ablation. We categorized them into three groups: AF ablation without CF and AI information (no-CF group, n = 63), with CF without AI (CF-only group, n = 49), and with optimal AI-guided ablation (AI group, n = 61). Early (within 3 months, ER) and late (from 3 months to 1 year, LR) AF recurrence after ablation was assessed. Procedure-related complications were also evaluated.ResultsThe baseline characteristics were similar among the 3 groups, excluding the baseline antiarrhythmic drug history. Additional substrate modification after pulmonary vein isolation was significantly low in frequency in the AI group (71.4%, no-CF; 69.4%, CF-only; 41.0%, AI, p = 0.001). The AI group had a shorter mean procedure-related time than the other groups. Both ER and LR of PeAF showed a trend of reduction with technological advances. With a short experience (less than 1 year), the CF-only group showed more ER and LR than that shown by the AI group. However, with a long experience (more than 1 year), ER and LR occurred similarly in the two groups. Procedure-related complications improved with technological advances.ConclusionAs ablation technology advanced, favorable clinical outcomes with short procedural times were observed. However, prospective, large multicenter studies are needed to verify these results.

Reconnection patterns after CLOSE-guided 50 W high-power-short-duration circumferential pulmonary vein isolation and substrate modification-PV reconnection might no longer be an issue.

Ablation of atrial fibrillation (AF) with high-power-short-duration (HPSD) radiofrequency (RF) technology is emerging as a new standard of care in many electrophysiology laboratories. While procedural short-term efficacy and efficiency is very promising, little is known about mid- to long-term effects of HPSD ablation for pulmonary vein isolation (PVI) and left atrial substrate modification. In a single-center registry, 412 AF procedures were performed in 400 individual patients using a standardized CLOSE protocol-guided fixed 50 W HPSD ablation, aiming for an ablation index (AI) of 400 on the posterior and 550 on the anterior wall. Additional substrate-tailored lines were performed when required. After a mean clinical follow-up of 337 ± 134 days, 15 patients suffered from AF recurrence beyond the blinding period. Twelve gave consent to the indicated reablation. Here, 11 of 12 patients had chronic isolation of all fourpulmonary veins (PV). In three of sixpatients, a reconnection of additional left atrial ablation lines was revealed. Ten out of 12 patients showed progressive fibrous atrial cardiomyopathy and required additional left atrial substrate modification or reisolation of left-atrial lines. During the follow-up no clinical case of atrioesophageal fistula was registered. No PV stenosis after initial HPSD PVI was documented. Patients requiring reablation of AF or other atrial tachycardia after a fixed 50 W HPSD circumferential PVI and substrate modification predominantly suffer from progressive fibrous atrial cardiomyopathy, while PV reconnection appears to be a rare cause of AF recurrence.

The feasibility and safety of substrate modification on the left atrial roof area using a cryoballoon in atrial fibrillation ablation

BackgroundData on additional substrate modification using a cryoballoon beyond cryoballoon pulmonary vein isolation (CB-PVI) is limited. We sought to evaluate the efficacy and safety of substrate modification on the left atrial roof area using CBs (LAR-CBs) for atrial fibrillation (AF) patients. MethodsEighty-one AF patients (70.0[62.5–77.0] years, 33 paroxysmal AF[PAF], 48 non-PAF) underwent LAR-CBs following CB-PVIs. Voltage maps were created with a high-resolution mapping system. Roof line conduction block was evaluated during the repeat procedure. ResultsThe total number of applications for the CB-PVI and LAR-CB were 5.0 ± 1.2 and 3.8 ± 0.7, and both were significantly greater in non-PAF than PAF patients. LA roof areas had continuous scar in 61/79(77.2%) patients, and the mean balloon temperature was significantly lower in patients with continuous scar than those without (−39.3 ± 3.8 vs. −36.0 ± 4.6 °C, p = 0.004). The single procedure 1-year AF freedom was 87.6% (7.5% on antiarrhythmic drug) and was similar between PAF and non-PAF patients (p = 0.14). Twelve (14.8%) patients underwent a second procedure 5.5(2.2–7.5) months later, and a mean of 1.3 ± 0.5 PVs were reconnected in 7/12(58.3%) patients. Electrical conduction block across the roof line was proven in 3/12(25.0%) patients. There were 6(7.4%) complications related to the procedures, including iatrogenic roof dependent atrial tachycardia, takotsubo cardiomyopathy, and severe pericarditis in 1, 1, and 2 patients, respectively. ConclusionsLA roof area substrate modification using CBs yielded a high arrhythmia freedom after single procedures. However, a low incidence of electrical conduction block across the line during the chronic phase and delayed complications were the major concerns.

Safety of high power and short duration ablation (70 watts over 5–7 seconds) in patients with persistent atrial fibrillation undergoing pulmonary vein isolation and additional substrate modification

Abstract Background In paroxysmal atrial fibrillation (AF), pulmonary vein isolation using HPSD has shown a promising success rate compared to ablation using conventional power settings, as well as a significant reduction in procedural and ablation time. In persistent atrial fibrillation, left atrial substrate modification seems to be a promising additional ablation approach besides pulmonary vein isolation (PVI). However, results after additional substrate ablation are not consistently positive, which may be related to non-transmural lesions and tissue oedema. An extended time of the procedure may also influence safety. Recent publications showed that HPSD ablation provides more sufficient lesions due to acute cell necrosis instead of cell oedema. Purpose The aim of this study is to evaluate the safety of HPSD ablation in patients undergoing ablation of persistent atrial fibrillation with PVI and additional substrate modification. Methods We studied and compared n=300 patients from our register undergoing the first ablation of persistent atrial fibrillation with HPSD settings (n=150) between May 2018 and January 2019 and standard settings (n=150) between July 2017 and January 2018. Patients were followed up for three months to report procedure-related adverse events. In all patients, a modified stepwise approach using PVI followed by electrogram-guided substrate modification and linear-ablation, if necessary, was performed. A HPSD ablation was performed with 70 watts with a maximum duration of 5–7 seconds. Catheter irrigation was set to 20 ml/min using the Flexability™ ablation catheter and the Ampere™ generator. The patients were compared with a historical cohort that underwent PVI using a conventional power protocol with 30–40 watts over 20–40 seconds, using the same ablation catheter. A transthoracic echocardiogram was performed in all patients after the ablation-procedure and on the following day. Duplex sonography or clinical control were performed to assess groin complications. Results Baseline characteristics and procedural data are shown in table 1. No significant difference in the complication rates in both groups was observed by a significant procedure-time reduction in HPSD-Group (2:13h vs 2:31h p&amp;lt;0,001) and overall low risk of the procedure. No deaths, thromboembolic complications or atrioesophageal fistula were registered. Complication rates with statistical relevancy are shown in table 2. Conclusion Complex ablation using PVI and additional substrate modification in persistent atrial fibrillation using HPSD seems to be equally as safe regarding procedure-related outcomes as standard power settings ablation and can significantly reduce the time of the overall procedure. Funding Acknowledgement Type of funding sources: None.

Find me if you can: lessons learned using the novel cartofinder algorithm in a routine workflow for catheter ablation of atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background CARTOFINDER allows for a simultaneous and automated detection of repetitive focal and rotational activations during electroanatomical mapping using a multi-electrode catheter in patients with atrial fibrillation (AF). Aim This study aimed to validate the CARTOFINDER algorithm for the detection of potential drivers for AF under routine clinical conditions and to access the effects of PVI and additional substrate modification on regions of interests (ROI) from CARTOFINDER mapping. Methods Forty-four consecutive patients underwent AF ablation for persistent AF using a 3D-mapping system with the novel integrated CARTOFINDER module. All patients presented with persistent AF and mapping was performed using a multi-electrode catheter. The ablation workflow was divided into the following steps: 1. 3D reconstruction of the right (RA) and left atrium (LA). 2. Identification of the individual ROIs separated for focal and rotational activity in the RA and LA. 3. Ablation index guided pulmonary vein isolation (PVI). 4. Repeat mapping for ROIs in the RA and LA. 5. Direct current electrical cardioversion. 6. Confirmation of persistent PVI and bipolar ultra-high density mapping of the RA and LA followed by substrate modification if there was evidence for local bipolar low-voltage in the LA. Results Acute PVI was achieved in all patients (100%). In 28% of these patients additional LA substrate modification was performed. AF termination was observed in 4 patients. Mean procedure duration was 137 ± 30 min, mapping time for ROIs in the RA was 8 ± 5 min and 11 ± 5 for the LA, respectively. A mean number of 149 ± 82 ROIs were revealed from CARTOFINDER. In the LA, focal activity was predominantly observed inside the LA appendage (LAA) and in close relationship to the pulmonary vein ostia. The majority of rotational activities was found along the mitral valve annulus. In the RA, the majority of ROIs was found at the septum and in close relationship to the RA appendage. During re-mapping for ROIs after AF ablation we observed the elimination of ROIs close to the linear ablation set for PVI. In addition, rotational activity could not be re-identified at repeat mapping. Conclusions ROIs could be discriminated and visualized utilizing CARTOFINDER in all patients. These ROIs might potentially be an additional and individual ablation target beyond PVI in patients with persistent AF.

Targeting Bachmann's bundle in hybrid ablation for long-standing persistent atrial fibrillation: a proof of concept study.

Catheter-based or surgical procedures in patients with long-standing persistent atrial fibrillation (LSPAF) remain a challenge. As a result, different approaches including hybrid (surgical and endocardial) ablation have been developed. Bachmann's bundle (BB) is a mainly epicardial structure capable of sustaining arrhythmic reentry that could be involved in the development and perpetuation of atrial fibrillation. We investigated the efficacy and safety of an adjunctive BB ablation in LSPAF patients undergoing hybrid ablation. In a two-arm non-randomized study, consecutive LSPAF patients undergoing epicardial isolation of pulmonary veins with left atrial posterior wall (box lesion) with (n = 30, BB group) and without additional BB ablation (n = 30, CONV group) were enrolled in the study. All patients underwent an endocardial procedure within 6 weeks post-surgery to assess for potential lesion gaps and additional atrial substrate modification. The primary endpoint was freedom from AF through 12 months of follow-up. The two-staged hybrid ablation was successfully completed in all patients. One-year freedom from atrial arrhythmias recurrence rates was 96.6% in the BB group vs 76.6% in the CONV group (p = 0.025). At procedure completion, 30 (100%) and 17 (56%) patients had a spontaneous cardioversion in BB and CONV group, respectively (p < 0.001). No significant differences in quality of life or complication rates were observed. This initial experience shows, for the first time, that adjunctive BB ablation in the setting of hybrid ablation for LSPAF is a feasible and effective approach in increasing maintenance of sinus rhythm without increasing complication rates.