Background:Esophageal fistula (EF) is a rare but devastating complication following atrial fibrillation (AF) ablation. Data regarding the impact of age on EF are scarce. Objective:To study the impact of age on the management and prognosis of EF following catheter ablation for AF. Methods:The POTTER-AF study is a worldwide registry on EF following catheter ablation for AF. A total of 553,729 patients underwent AF ablation in 214 centers between 1996 and 2022. Of them, 138 patients experienced EF, and data regarding age, management, and prognosis were available in 113 patients. The population was divided based on the median age. Results:The median age was 63 years; 54 patients were <63 years old (Group 1), and 59 patients were ≥63 years old (Group 2). The groups were similar regarding procedural characteristics. The older population had a shorter time to symptom onset [15.0 (6.0, 21.0) vs. 21.0 (10.0, 25.3) days; p = 0.031]. Group 2 was less likely to receive a brain CT or MRI for diagnosis (25.9% vs. 45.3%; p = 0.046). The older population was more likely to undergo endoscopic treatment without surgery (27.6% vs. 11.3%; p = 0.035). Conservative and surgical treatments were used in similar proportions. A trend toward higher fatality was noted in the older patients (72.9% vs. 56.6%; p = 0.078). Conclusion:The older population had a shorter time to symptom onset, was less likely to receive a brain CT or MRI, and more likely to be treated by an endoscopic approach only. The older patient group showed a trend toward a higher fatality.

BACKGROUND:Beyond pulmonary veins isolation (PVI), the ablation strategy that has prevailed over the past two decades remains controversial: (1) the left atrium partition using linear lesions ("cox-maze" strategy); (2) the mapping of the left atrium in atrial fibrillation (AF) to identify and localize the arrhythmia sources. Both methods have failed to demonstrate superiority compared to PVI alone. Whether the addition of a systematic vein of Marshall (VOM) ethanol infusion and empirical linear ablation to PVI (Marshall-Plan) improves outcomes in patients with persistent AF remains to be demonstrated. OBJECTIVES:To compare the 2-year freedom from any atrial arrhythmia (atrial fibrillation [AF]/atrial tachycardia [AT]) between the Marshall-Plan approach and the PVI approach in patients with persistent AF. METHODS:The Marshall Plan is a multicenter, prospective, randomized, parallel- group, controlled clinical trial of superiority conducted in nine tertiary care centers across Europe (8 centers in France, 1 center in Belgium). A total of 262 patients will be randomized in two arms: Marshall-Plan, consisting of PVI with additional ablation, including vein of Marshall ethanol infusion, and lines of block at the mitral, dome, and cavotricuspid isthmuses versus PVI alone. The main outcome will be the 2-year freedom from any arrhythmia AF/AT <30 seconds) after a single ablation procedure with or without antiarrhythmic medication. CONCLUSIONS:This randomized trial aims to determine the success and safety of adjunctive VOM ethanol infusion and linear ablation to PVI in patients with persistent AF. REGISTRATION:URL: https://www. CLINICALTRIALS:gov; Unique identifier: NCT04681872.

Background:Catheter ablation is a highly effective treatment of atrioventricular accessory pathways (APs). Catheter-induced mechanical trauma of the AP is not infrequent during electrophysiology study and can lead to procedure discontinuation. We present an alternative method to successfully ablate a persistently traumatized AP. Case summary:A 15-year-old patient was referred for ablation of a symptomatic parahisian AP. Unfortunately, the AP was mechanically traumatized during catheter placement, and conduction did not resume after a 45-min waiting period. We proceeded to determine the ventricular insertion of the AP. Pace mapping was performed at the ventricular aspect of the tricuspid annulus with bipolar pacing from the ablation catheter. Using electroanatomic mapping, a correlation map between the maximally pre-excited QRS morphology (recorded at the beginning of the electrophysiological study) and the pace-mapped QRS was displayed. The highest correlation was 94%. The area delimited by the 3 best pace-map matching points was considered the target area, and radiofrequency applications were delivered. No recurrence of pre-excitation or palpitations were observed during 6 months of follow-up. Discussion:Determining the distal ventricular insertion of a mechanically traumatized AP is feasible, by comparing a maximally pre-excited QRS with the paced-mapped QRS. Electroanatomic correlation mapping may help delineate a limited target area before ablation.

Substrate ablation strategies in addition to pulmonary vein isolation (PVI) for the maintenance of sinus rhythm (SR) are still debated. Targeting low voltage areas (LVA) in addition to PVI may represent an efficient strategy for the ablation of persistent atrial fibrillation (AF). SCAR-AF study (ablation of LVA during sinus rhythm) was a multicenter, prospective, randomized trial, evaluating the effect of LVA ablation in addition to PVI for persistent AF on SR maintenance. From September 2019 to August 2021, patients with de novo persistent AF were included in the study. After LA mapping guided by a 3D mapping system, patients were divided according to the presence or absence of LVA. Patients without LVA were treated by PVI only (Group A). Patients with LVA were randomized to PVI only (Group B) or PVI + ablation of LVA (Group C). LVA was defined as voltage mapping with bipolar atrial voltage <0.5 mV. The primary endpoint was freedom from atrial arrhythmias, after a single ablation procedure. A total of 211 patients (Sex male: 73%, Mean Age 63.8+/-9.3 years, CHADS-VASC 2.1, long standing AF 33.5%). After 18 months FU, atrial-arrhythmia-free survival did not differ significantly between the 3 groups, 79% in Group A, 75.7% in Group B, 73.1% in Group C (Group A vs Group B: HR: 1.28; 95% CI: 0.64-2.55, p = .48, Group B vs Group C: HR 95%CI: 0.67-2.45; p = 0.45). Multivariate analysis showed that presence of LVA was associated with age (years) (HR 1.11 CI 1.06 – 1.16, p < 0.001) and inversely correlated with BMI (kg/m²) (HR 0.93, CI 0.87 – 0.99, p 0.029) and current smoking. In this randomized trial, PVI plus ablation of LVA did not significantly improved outcomes in patients with persistent AF. LVA may represent a marker of severe atrial cardiomyopathy.

Background:Most data on atrial fibrillation (AF) ablation using the first available pentaspline pulsed field ablation (PFA) catheter (Farapulse, Boston Scientific Inc) come from retrospective center-level registries collected in highly experienced centers. Objective:This study aimed to provide exhaustive and prospective patient-level data on this new ablation modality. Methods:FRANCE-PFA is a nationwide registry (NCT06497933) that included all patients undergoing a first AF ablation using the pentaspline PFA catheter since the introduction of this technology in France. All French centers using this technology participated. Procedural data were prospectively collected at a patient level. Results:This registry included 5223 patients from 33 centers between March 2021 and February 2024 (mean age 65 ± 11 years, 55.4% paroxysmal AF). The procedure duration was 54 ± 23 minutes. Acute pulmonary vein isolation was achieved in 5211 patients (99.8%). The total number of PFA applications was 50 ± 22 with >70 applications in 746 patients (14.3%). Pulmonary vein isolation only was performed in 64.7% of patients (82.7% of paroxysmal AF, 44.5% of persistent AF, and 26.6% of long-standing persistent AF). The most common location for additional PFA lesion sets was the left atrium posterior wall in 1335 patients (25.6%), left atrium roof in 999 patients (19.1%), and mitral isthmus in 514 patients (9.8%). Major complications occurred in 50 patients (0.96%), with no esophageal complication or symptomatic phrenic nerve palsy reported in past hospital discharge. Conclusion:In this prospective and nationwide registry, AF ablation using the pentaspline PFA catheter seemed to be safe and acutely efficient, despite considerable heterogeneity in the number of patients treated at each center. Trial Registration:NCT06497933.

BACKGROUND:Targeting low-voltage areas (LVAs) in addition to pulmonary vein isolation (PVI) can improve ablation outcome in persistent atrial fibrillation (AF). OBJECTIVE:SCAR-AF was a multicenter, prospective, randomized trial, evaluating LVA ablation plus PVI for persistent AF. METHODS:Patients with de novo persistent AF were recruited (9 referral centers in France) into the SCAR-AF study (September 2019 to August 2021). Patients without LVA were treated with PVI alone (PVI-), and those with LVA were randomized to either PVI alone (PVI+) or PVI plus LVA ablation (PVI + LVA). The primary outcome was freedom from atrial arrhythmias (AF/atrial tachycardia) after a single procedure. RESULTS:A total of 211 patients (73.5% men, mean ± standard deviation age 63.8 ± 9.3 years, CHA2DS2-VASc score 2.1, long-standing AF 44.5%) were included. At 18-month follow-up, the incidence of atrial-arrhythmia-free survival did not differ between groups (79.0% in PVI-, 75.7% in PVI+, and 73.1% in PVI + LVA; PVI- vs PVI+, hazard ratio (HR) 1.28, 95% confidence interval [CI] 0.64-2.55, P = .48; PVI+ vs PVI + LVA, HR 1.28; 95% CI 0.67-2.45, P = .45). On multivariable analysis, presence of LVA was associated with advancing age (HR 1.11, 95% CI 1.06-1.16, P < .001) and was inversely correlated with body mass index (HR 0.93, 95% CI 0.87-0.99, P = .029) and smoking. CONCLUSION:In this randomized trial, PVI plus LVA ablation did not improve outcomes in patients with persistent AF. LVA may represent a marker of atrial cardiomyopathy, but its presence does not seem to be an effective target in persistent AF.

Pulsed field ablation (PFA) is an emerging technology for the treatment of atrial fibrillation (AF), for which pre-clinical and early-stage clinical data are suggestive of some degree of preferentiality to myocardial tissue ablation without damage to adjacent structures. Here in the MANIFEST-17K study we assessed the safety of PFA by studying the post-approval use of this treatment modality. Of the 116 centers performing post-approval PFA with a pentaspline catheter, data were received from 106 centers (91.4% participation) regarding 17,642 patients undergoing PFA (mean age 64, 34.7% female, 57.8% paroxysmal AF and 35.2% persistent AF). No esophageal complications, pulmonary vein stenosis or persistent phrenic palsy was reported (transient palsy was reported in 0.06% of patients; 11 of 17,642). Major complications, reported for similar to 1% of patients (173 of 17,642), were pericardial tamponade (0.36%; 63 of 17,642) and vascular events (0.30%; 53 of 17,642). Stroke was rare (0.12%; 22 of 17,642) and death was even rarer (0.03%; 5 of 17,642). Unexpected complications of PFA were coronary arterial spasm in 0.14% of patients (25 of 17,642) and hemolysis-related acute renal failure necessitating hemodialysis in 0.03% of patients (5 of 17,642). Taken together, these data indicate that PFA demonstrates a favorable safety profile by avoiding much of the collateral damage seen with conventional thermal ablation. PFA has the potential to be transformative for the management of patients with AF.

BACKGROUND In repaired tetralogy of Fallot (TOF), little is known about characteristics of patients with rapid ventricular tachycardia (VT). Also, whether patients with a first episode of nonrapid VT may subsequently develop rapid VT or ventricular fibrillation (VF) has not been addressed.OBJECTIVES The objectives of this study were to compare patients with rapid VT/VF with those with nonrapid VT and to assess the evolution of VT cycle lengths (VTCLs) overtime. METHODS Data were analyzed from a nationwide registry including all patients with TOF and implantable cardioverter-defibrillator (ICD) since 2000. Patients with >1 VT episode with VTCL <250 ms (240 beats/min) formed the rapid VT/VF group.RESULTS Of 144 patients (mean age 42.0 & PLUSMN; 12.7 years; 104 [72%] men), 61 (42%) had at least 1 VT/VF episode, including 28 patients with rapid VT/VF (46%), during a median follow-up of 6.3 years (interquartile range 2.2-10.3 years). Compared with patients in the nonrapid VT group, those in the rapid VT/VF group were significantly younger at ICD implantation (35.2 & PLUSMN; 12.6 years vs 41.5 & PLUSMN; 11.2 years; P = .04), had more frequently a history of cardiac arrest (8 [29%] vs 2 [6%]; P = .02), less frequently a history of atrial arrhythmia (11 [42%] vs 22 [69%]; P = .004), and higher right ventricular ejection fraction (43.3% & PLUSMN; 10.3% vs 36.6% & PLUSMN; 11.2%; P = .04). The median VTCL of VT/VF episodes was 325 ms (interquartile range 235-429 ms). None of the patients with a first documented nonrapid VT episode had rapid VT/VF during follow-up.CONCLUSION Patients with TOF and rapid VT/VF had distinct clinical characteristics. The relatively low variation of VTCL over time suggests a room for catheter ablation without a backup ICD in selected patients with well-tolerated VT.

AIMS:Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management, and outcome are sparse. METHODS AND RESULTS:This international multicentre registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553 729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed, at 214 centres in 35 countries. In 78 centres 138 patients [0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (P < 0.0001)] were diagnosed with an oesophageal fistula. Peri-procedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8% and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) [odds ratio 7.463 (2.414, 23.072) P < 0.001]. CONCLUSION:Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

INTRODUCTION:Multiple groups have reported on the usefulness of ablating in atrial regions exhibiting abnormal electrograms during atrial fibrillation (AF). Still, previous studies have suggested that ablation outcomes are highly operator- and center-dependent. This study sought to evaluate a novel machine learning software algorithm named VX1 (Volta Medical), trained to adjudicate multipolar electrogram dispersion. METHODS:This study was a prospective, multicentric, nonrandomized study conducted to assess the feasibility of generating VX1 dispersion maps. In 85 patients, 8 centers, and 17 operators, we compared the acute and long-term outcomes after ablation in regions exhibiting dispersion between primary and satellite centers. We also compared outcomes to a control group in which dispersion-guided ablation was performed visually by trained operators. RESULTS:The study population included 29% of long-standing persistent AF. AF termination occurred in 92% and 83% of the patients in primary and satellite centers, respectively, p = 0.31. The average rate of freedom from documented AF, with or without antiarrhythmic drugs (AADs), was 86% after a single procedure, and 89% after an average of 1.3 procedures per patient (p = 0.4). The rate of freedom from any documented atrial arrhythmia, with or without AADs, was 54% and 73% after a single or an average of 1.3 procedures per patient, respectively (p < 0.001). No statistically significant differences between outcomes of the primary versus satellite centers were observed for one (p = 0.8) or multiple procedures (p = 0.4), or between outcomes of the entire study population versus the control group (p > 0.2). Interestingly, intraprocedural AF termination and type of recurrent arrhythmia (i.e., AF vs. AT) appear to be predictors of the subsequent clinical course. CONCLUSION:VX1, an expertise-based artificial intelligence software solution, allowed for robust center-to-center standardization of acute and long-term ablation outcomes after electrogram-based ablation.

Aim. - We aimed to describe temporal trends in volume and outcomes of catheter ablation in patients with ACHD. Methods. - This was a retrospective observational study including all consecutive patients with ACHD undergoing attempted catheter ablation in a large tertiary referral centre over a 15-year period. Acute procedural success rate and freedom from recurrence at 12 and 24 months were analysed. Results. - From November 2004 to November 2019, 302 catheter ablations were performed in 221 patients with ACHD (mean age 43.6 +/- 15.0 years; 58.9% male sex). The annual number of catheter ablations increased progressively from four to 60 cases per year (P < 0.001). Intra-atrial reentrant tachycardia/focal atrial tachycardia was the most common arrhythmia (n = 217, 71.9%). Over the study period, acute procedural success rate increased from 45.0% to 93.4% (P < 0.001). Use of irrigated catheters (odds ratio [OR] 4.03, 95% confidence interval [CI] 1.86-8.55), a three-dimensional mapping system (OR 3.70, 95% CI 1.72-7.74), contact force catheters (OR 3.60, 95% CI 1.81-7.38) and high-density mapping (OR 3.69, 95% CI 1.82-8.14) were associated with acute procedural success. The rate of freedom from any recurrence at 12 months increased from 29.4% to 66.2% (P = 0.001). Seven (2.3%) non-fatal complications occurred. Conclusions. - The number of catheter ablation procedures in patients with ACHD has increased considerably over the past 15 years. Growing experience and advances in ablative technologies appear to be associated with a significant improvement in acute and mid-term outcomes. (c) 2021 Elsevier Masson SAS. All rights reserved.

RF ablation is a standard practice approach for the symptomatic AF. The interest of substrate ablation, completing pulmonary vein isolation is controversial. The current ablation strategy for persistent AF ablation is a step-by step guided approach: PVI is most often followed by a large ablation of fragmented electrograms identified in AF or completed by linear ablation, but this current ablation strategies have shown a limited success rate with frequent arrhythmia recurrences. Recent studies suggest that the atrial arrhythmogenic sites are related to regions with heterogeneities and increased fibrosis, which is detected by reduced bipolar voltage areas. Defragmentation low voltage areas (LVA) in sinus rhythm (SR) in addition to PVI may represent an efficient strategy for the ablation of persistent AF. This is a prospective multicentric interventional study in France. Inclusion criteria: minimum age 18 years, patients with persistent AF ablation, no specific indication restrictions or equipment used regardless of the outcome of the procedure. Number of patients: 210 patients included in 9 centres. Three groups will be constituted: Group 1: PVI without LVA identified, group 2: PVI only, with LVA identified but defragmentation will not be carried out and group 3: PVI with LVA identified and defragmentation will be carried out. Definition of LVA in SR: all potentials < 1 mV, fragmented signal: more than 5 deflexions, duration > 55 ms. Inducibility of AF is realised at the end of the procedure. Usual blanking period of 3 months. Follow-up: clinical evaluation, ECG, and 24h-holter ECG at 6, 12 and 18 months. Primary outcome: recurrence of AF at 18 months. Secondary outcomes: comparison of efficiency and safety of the procedures, procedural data (X-ray data, RF duration, AF inducibility), organised atrial tachycaria occurring during FU.

OBJECTIVES:The aim of this study was to assess the persistence of left atrial (LA) lesions created by ethanol infusion in the vein of Marshall (EIVM) by electroanatomical mapping on repeat catheter ablation for recurrent atrial tachyarrhythmia.BACKGROUND:Little is known about the durability of LA lesions created by EIVM.METHODS:The study included consecutive patients who underwent EIVM for persistent atrial fibrillation or perimitral LA flutter (index procedure) and repeat catheter ablation for recurrent atrial tachyarrhythmia or atrial fibrillation at a single center between January 2019 and April 2020. The acute effect of EIVM was assessed at the index procedure by comparing the area of bipolar voltage <0.05 mV in the vein of Marshall (VOM) region before and immediately after EIVM. The long-term effect of EIVM was assessed by comparing this area in the VOM region between the redo procedure and the index procedure.RESULTS:Twenty-four consecutive patients (mean age 68.6 ± 6.1 years, 58% men) underwent redo procedures after previous EIVM for persistent atrial fibrillation (n = 21 [88%]) or perimitral LA flutter (n = 5 [21%]). In each patient, the EIVM-related lesion persisted, with a chronic scar in the VOM region (median 13.1 cm2 [interquartile range: 8.1-15.9 cm2] vs 12.4 cm2 [interquartile range: 7.6-15.7 cm2] acutely, respectively). One quarter of patients (9 of 20) had late mitral isthmus reconnection, which was located at the mitral annular edge or in the coronary sinus.CONCLUSIONS:Atrial lesions created by EIVM are durable, which reinforces the efficacy profile of EIVM. Reconduction sites in the mitral isthmus are located at the edge of the scar and in the coronary sinus.

INTRODUCTION:Catheter ablation (CA) of atrial tachyarrhythmias (ATs) in patients with complex congenital heart disease (CHD) often requires technically challenging transbaffle or transconduit puncture. The aim was to assess the feasibility and safety of transbaffle/transconduit puncture based on computed tomography (CT) three-dimensional (3D) reconstruction merged with electro-anatomical mapping (EAM) without per-procedure echocardiographic guidance.METHODS AND RESULTS:We included 18 consecutive CHD patients in two centers who had atrial-switch or Fontan surgery and underwent CA of AT by an antegrade approach requiring intracardiac puncture. Twelve patients with atrial-switch surgery and six patients with extracardiac Fontan surgery were referred for CA of AT. Cardiac CT with 3D reconstruction was performed before the procedure. The 3D volume of the systemic venous atrium or extracardiac conduit acquired by EAM was merged with the corresponding CT 3D reconstruction. The ablation catheter was positioned at the optimal puncture site. Under fluoroscopic guidance, the needle was positioned next to the ablation and the puncture was performed. Balloon expansion of the puncture site was performed in every case of transconduit puncture and in two (17%) cases of transbaffle puncture. Overall, 17 intra-atrial reentrant tachycarrythmias and 9 focal ATs were successfully ablated, with no acute complications. The median time to access the pulmonary atrium was 78.5 minutes (range, 55-185) and total median fluoroscopy time was 23 minutes (range, 7-53).CONCLUSIONS:Transbaffle and transconduit punctures can be performed safely in CHD patients by using a simple technique relying on CT 3D reconstruction and EAM.

BACKGROUND While outcomes of intra-atrial reentrant/focal atrial tachycardia (IART/FAT) catheter ablation have considerably improved in adult congenital heart disease (ACHD), recurrences remain common with different circuits frequently encountered. OBJECTIVE We aimed to assess the value of programmed atrial stimulation after successful clinical IART/FAT catheter ablation in patients with ACHD. METHODS This is a retrospective study including all patients with ACHD undergoing IART/FAT catheter ablation in a tertiary center. After successful catheter ablation of clinical arrhythmia, survival free from arrhythmia recurrence was analyzed according to whether all inducible IARTs/FATs were targeted. RESULTS From 2004 to 2020, 238 IART/FAT catheter ablation procedures were performed (mean age 44.1 +/- 15.0 years; 61.3% men). Acute procedural success of clinical arrhythmia was achieved in 208 procedures (87.4%). Among 122 procedures with programmed atrial stimulation (58.7%), at least 1 other IART/FAT was induced in 61 patients (50 0 /o). All inducible IARTs/FATs were ablated in 54 pa- tients (88.5%), whereas 7 patients (11.5%) presented with at least 1 nontargeted inducible IART/FAT. Patients with nontargeted inducible IART/FAT had a higher risk of atrial arrhythmia episodes than did inducible patients treated with ablation of all IARTs/FATs (hazard ratio 5.7; 95% confidence interval 1.7-18.4; P = .004), with 12-month atrial arrhythmias recurrence rates of 22.9% and 77.7%, respectively. Inducible patients with successful ablation of all IARTs/FATs had a risk of recurrence similar to that of noninducible patients (hazard ratio 0.6; 95% confidence interval 0.3-1.3; P = .215). CONCLUSION Beyond clinical IART/FAT catheter ablation in patients with ACHD, our findings suggest the interest of systematically targeting all remaining inducible arrhythmias, irrespective of whether previously documented.

With the growing population of adults with congenital heart disease (ACHD), the number of catheter ablation procedures is expected to increase over time. We aimed to describe temporal trends in volume and outcomes of catheter ablation procedures in ACHD patients in a large tertiary center. Retrospective observational study including all consecutive ACHD patients undergoing catheter ablation in a tertiary reference center over a 15-year period. Acute procedural success rate (including complete success in case of non-inducibility of any arrhythmia at the end of the procedure) as well as freedom from recurrence at 12 months were analyzed. From November 2004 to November 2019, 302 catheter ablations in 221 ACHD patients (43.6±15.0 years, 58.9% males) were performed. The annual number of catheter ablation increased progressively from 4 to 60 by year (p<0.001). Intra-atrial reentrant tachycardia/focal atrial tachycardia was the most common targeted arrhythmia (n=217, 71.9%). Over the study period, acute procedural success rate increased from 45.0% to 93.3% (p<0.001), including complete acute procedural success from 45.0% to 88.1% (p<0.001) (Figure 1). The use of irrigated catheters (30.0% to 94.8%, p<0.001), 3D-mapping systems (60.0% to 96.3%, p<0.001), contact force catheters (0.0% to 91.9%, <0.001), and high-density mapping (0.0% to 71.9%, p<0.01) increased significantly. Use of irrigated catheters (OR=3.96, 95% CI: 1.79–8.55), 3D-mapping system (OR=3.55, 95% CI: 1.62–7.55), contact force catheters (OR=3.46, 95% CI: 1.71–7.25), and high-density mapping (OR=3.85, 95% CI: 1.60–7.26) were associated with acute procedural success. The rate of freedom from any recurrence at 12 months increased from 29.4% to 66.2% (p=0.001). Seven (2.3%) non-fatal complications occurred. The number of catheter ablation procedures in ACHD patients has considerably increased over the last 15 years. Advances in ablative technologies appear to be associated with a low rate of complications and a significant improvement in acute and midterm outcomes. Evolution of acute procedural success Type of funding source: None

Central illustration. Evolution of acute procedural success rates. Partial acute procedural success was defined as termination of clinical arrhythmia with subsequent verification of bidirectional conduction block with additional arrhythmias induced not targeted or not successfully targeted or absence of final programmed stimulation performance. Complete acute procedural success was defined as termination of clinical arrhythmia(s) with subsequent verification of bidirectional conduction block and non-inducibility of other arrhythmias or successful ablation of all secondary arrhythmias induced (except inducible atrial fibrillation [AF]). Final programmed stimulation performance was not required to consider complete acute procedural success when the targeted arrhythmia was AF, premature ventricular contraction or atrioventricular node. The red line represents the rate of final programmed stimulation. FAT: focal atrial tachycardia; IART: intra-atrial reentrant tachycardia.

Introduction: The success rate of cavo-tricuspid isthmus (CTI) ablation to treat right common flutter is high, up to 95%, but needs bidirectional block confirmation, requiring 2 or 3 catheters. We describe a new pacing technic using a single catheter to ablate and confirm CTI block with differential PR interval measurements. Methods: We included 61 patients from 5 centers that were referred for CTI ablation. All patients had CTI ablation and the CTI block was confirmed by differential pacing using 2 or 3 catheters. The new method consisted in measuring PR interval on the surface ECG using pacing from the tip of ablation catheter on the lateral side (lateral delay) and septal side (coronary sinus ostium) of the CTI line (difference =delta PR interval) before and after CTI ablation. We analyzed the value of delta PR interval to predict bidirectional CTI block as confirmed by standard methods. Results: Among our patient’s population (63±12 years-old), 39 patients were ablated during sinus rhythm while 22 during common flutter. CTI block was achieved in all patients but one. Then, Lateral delay and delta PR interval increased significantly after validation of CTI block (257±42ms vs 318±50ms and 32±23 vs 96±22ms, p<0.0001, respectively). A cut-off ≥70ms of delta PR interval had a 100% of sensitivity and specificity to predict bidirectional CTI block. Conclusion: A single catheter ablation approach to perform CTI line based on surface ECG PR interval measurement is feasible. After ablation, CTI block