Cavotricuspid Isthmus Ablation Research Articles

Wave speed mapping visualizes the cavotricuspid isthmus reconnection area: A case report.

In addition to the reentrant map, the wave speed map can be helpful in accurately identifying the CTI gap during radiofrequency application for atrial flutter(AFL). However, in complex cases involving extensive scarring and multiple low-velocity local areas, this technique may not be useful. A 73-year-old male patient with a history of pulmonary vein isolation and cavotricuspid isthmus ablation underwent a second catheter ablation owing to recurrent atrial flutter (AFL). The AFL was diagnosed as cavotricuspid isthmus-dependent AFL caused by the reconnection of the previous cavotricuspid isthmus ablation. Wave speed mapping was performed at the same site, and results comprehensively revealed a low-velocity local area. The AFL was terminated after the first radiofrequency application, and the block line was easily completed. Therefore, this technique could be an adjunctive tool for cavotricuspid isthmus gap identification and minimal radiofrequency application.

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.

Median dose area product and fluoroscopy time have stabilized on a low level during the last years: data from the swedish national catheter ablation registry

Abstract Background Despite the utilization of 3D-mapping systems, the use of fluoroscopy is still necessary in most procedures of catheter ablations of arrhythmias, but associated with serious health risks to both patients and operators. However, given the rapid improvement of the 3D-mapping systems, the usage of fluoroscopy has likely decreased during the past 15 years. Purpose The purpose of this study was to explore trends over time in usage of fluoroscopy in catheter ablation for all arrhythmias. Methods The Swedish Catheter Ablation Registry covers virtually all (>97%) catheter ablations performed in Sweden since 2005. Patients >18 years of age undergoing catheter ablation from January 1st 2006 to December 31st 2020 were included. Periprocedural data; median dose area product and fluoroscopy time were analyzed and compared. Periprocedural data were compared between 2006, 2015 and 2020 to find possible trends. Results A total of 61242 procedures were performed during the study period. The breakdown between the different arrhythmias was: 3% ventricular tachycardia (VT), 3% premature ventricular complex (PVC), 5% atrial tachycardia (AT), 7% atrioventricular junction ablation (AVJ), 10% atrioventricular reentry tachycardia (AVRT), 14% cavotricuspid isthmus ablation (CTI), 20% atrioventricular nodal reentry tachycardia (AVNRT) and 39% atrial fibrillation (AF). In 2006, the median fluoroscopy duration for AF, VT and PVC were recorded at 41, 32 and 37 minutes, respectively. Subsequently in 2015 the corresponding times were recorded at 14, 8 and 13 minutes. In 2020 respective procedures had a median fluoroscopy time of 11, 10 and 18 minutes (p< 0.001 for trend for all ablations). In 2006 median dose area product for AF, VT and PVC were 3998 cGycm2, 4300 cGycm2, and 5138 cGycm2, respectively. By 2015 the median dose area product had decreased to 1005 cGycm2, 432 cGycm2 and 1123 cGycm2 respectively. In 2020 the median dose area product had decreased further to 524 cGycm2, 380 cGycm2 and 848 cGycm2 (p<0.001 for trends for all ablations). See figure 1 for all procedures. Conclusion Fluoroscopy time and median dose area product have decreased significantly over a 15-year period and have stabilized on a low level over the last 5 years. Given the associated risks, efforts to further reduce radiation exposure are clearly warranted.Median dose area product

Participation of epicardial connection in transverse conduction across the crista terminalis in patients with upper and lower loop reentry atrial tachycardias

Abstract Background The crista terminalis (CT) sometimes serves as a partial or complete conduction barrier, which is rate- and site-dependent. The basis, location and extent of the transverse conduction across the CT have been controversial. The pseudo-focal activation pattern indicates passive activation from the anatomically opposite chamber or structure. We previously reported cases of transverse CT conduction exhibiting a pseudo-focal activation pattern, indicating the CT conduction utilizing an epicardial connection (EC) in patients with upper loop reentry (ULR) atrial tachycardia (AT). Purpose This study aimed to investigate the prevalence and characteristics of transverse CT conduction using a high-resolution electroanatomical mapping system during CT-dependent AT and to compare between the ULR and lower loop reentry (LLR) ATs. Methods A total of 119 consecutive patients with macroreentrant AT were studied. The diagnosis of ULR/LLR AT was made based on endocardial activation mapping and entrainment pacing obtained from various sites around the superior/inferior vena cava. Transverse CT conduction utilizing an EC was defined as follows; (1) a centrifugal activation pattern with the earliest activation (EA) site >5 mm away from the CT, (2) later activation observed between the EA and the CT, and (3) the EA site exhibiting a pseudo-focal activation pattern (multiple breakthroughs or a small r wave on unipolar electrogram). Results Eighteen (15.1%) of the 119 patients were diagnosed with CT-dependent AT (15 men; median age, 71.5 years; AT cycle length, 265 ms; left atrial diameter, 42.5 mm; left ventricular ejection fraction, 49%). The 18 patients were divided into 2 groups: 9 patients with ULR and 9 with LLR AT. There were no significant differences in clinical characteristics (sex, history of cardiac surgery and organic heat disease) between ULR and LLR groups. Transverse CT conduction utilizing EC was more frequently observed in the ULR group than in the LLR group [77.8% (7/9) vs 22.2% (2/9), P=0.05]. In all patients with transverse CT conduction utilizing EC, scars extended along the CT. AT cycle length was significantly longer in the ULR group than in the LLR group (295 vs 235 ms, p=0.001). All ATs were successfully eliminated by radiofrequency ablation at the breakthrough sites and/or along the CT in ULR patients or by cavotricuspid isthmus ablation in LLR patients. Conclusions Half (9/18) of the patients with CT-dependent AT exhibited transverse CT conduction with a pseudo-focal activation pattern, suggesting the existence of an EC between the sinus venosus and the right auricle. The high prevalence of the pseudo-focal pattern in patients with the ULR compared to those with the LLR may provide insights into mechanisms.Figure1Figure2

Digital health in the EP lab: routine implementation of remote access and technical support for complex ablation procedures

Abstract Background Complex electrophysiological procedures are performed using three-dimensional (3D) electroanatomical mapping (EAM) systems, which are usually operated on site, by field technical engineers (FTE). Due to a lack of skilled personnel, the engineers usually must travel between different hospitals and the procedures have to be planed in advance. Remote access (RA) technologies were recently implemented in clinical practice, aiming to increase the flexibility in the EP lab and maximise healthcare resources use. Methods Electroanatomical mapping was performed remotely by means of an integrated audio-visual solution for RA. The operator and the FTE communicated exclusively using the RA system, while the latter worked only in home office. Consecutive procedures were prospectively enrolled and analysed in terms of indication, procedural characteristics, feasibility and saved travelled time by the FTA. Results Between September 2022 and July 2023, a total of 133 EP procedures were performed in a high volume, tertiary electrophysiological centre in Germany. The mean age was 67 (57.5, 75.5) years. Women represented 39.8% of the population. The median BMI was 26.2 (23.1, 30.3) Kg/m2. A total of 56 (42.1%) patients underwent an atrial fibrillation ablation procedure (37.5% paroxysmal), 22 (16.5%) an atrial tachycardia ablation, 13 (9.8%) cavotricuspid isthmus ablation, 15 (11.3%) supraventricular tachycardia ablation, 14 (10.5%) a premature ventricular contraction ablation, 12 (9%) ventricular tachycardia ablations and 1 patient an electrophysiological diagnostic study. The median time length of procedure was 130 (96.5, 168) minutes. The median number of radiofrequency applications was 63.5 (22.3, 109.5), while the median RF time was 14.2 (6.9, 25.1) minutes. The fluoroscopy time was 9.2 (6.5, 12.6) minutes, with a median radiation dose of 408.5 (233.0, 631.8) cGy x cm2. The median amount of contrast media was 40 (8.75, 50.0) ml and the median amount of heparin administered was 12000 (8000, 16000) UI. Protamine was used in 9 cases, with a median of 7000 (5000, 7000) UI. Except for one supraventricular procedure, where no arrhythmia induction was possible, all procedures were successful. One major complication was observed. In one case, the internet-based headphone connection was not stable. Therefore, the communication was established via a conventional smartphone. No change to on-site support was needed. The travel time reduction was available in 130 cases. In total, 290 travel hours could be saved. Conclusion The routine implementation of RA for complex EP procedures proved to be safe and efficient. This approach has the potential to increase the feasibility in case of emergency procedures, reduce travel times for FTE and streamline healthcare resources allocation.

Left atrial substrate modification for persistent atrial fibrillation and left atrial macro or microreentrant tachycardia using a single-shot pulsed field ablation system - a single centre case series

Abstract Background Pulsed field ablation (PFA) is a novel ablation technique for pulmonary vein isolation (PVI) in patients with paroxysmal and persistent atrial fibrillation. However, data for efficacy and safety of PFA for left atrial substrate modification in patients with long-standing persistent atrial fibrillation (AF) and macro- as well as microreentrant atrial tachycardia (AT) is scarce. Aim Here we provide a retrospective, single-centre case series regarding efficacy and safety of left atrial substrate modification, using a single-shot PFA system. Methods and Results Over a period of 6 months, 8 patients with long-standing persistent AF and AT underwent Re-PVI with left atrial substrate modification using a single-shot PFA system. Median age was 63 years (IQR 58 - 75), and 4/8 of patients were female. Time from first diagnosis of AF was 7 years (IQR 4 –10). All but 1 patient underwent previous PVI (IQR 1-3) with (5/7) or without (2/7) prior substrate modification using radiofrequency ablation. On transthoracic echocardiography, all patients showed severe left- and right-atrial enlargement, with LA volume of 58 ml/m2 (IQR 49.7–72) and RA diameter of 62 mm (IQR 55-75). In 8 patients, 9 ATs and 2 typical flutters were treated with PFA. Following PVI, additional posterior wall isolation was performed in 6/8 patients, roof in 6/8, and anterior wall (between superior mitral anulus and RSPV) in 4/8 patients. In addition, 2/8 patients had cavotricuspid isthmus ablation for typical atrial flutter. All patients received atropine prior to PVI, as well as bolus of nitro-glycerine prior to PFA of anterior wall and/or cavotricuspid isthmus. Acute success rate was 100% and all ATs as well as typical flutter terminated with PFA. After median follow-up time of 88 days (IQR 61-112), 3 patients had a documented recurrence of AF/AT, in 2 of which electrical cardioversion was necessary. We observed no acute and/or chronic complications following PFA, i.e. no pericardial effusion/tamponade, TIA/stroke, myocardial infarction, coronary artery spasm, AV-block, bleeding, or atrioesophageal fistula. Conclusion In this small, single-centre case series, left atrial substrate modification for long-standing persistent AF and AT using a single-shot PFA system was safe and showed an excellent acute success rate.

Same-day discharge after atrial fibrillation ablation: is it equally safe?

Abstract Introduction Same-day discharge after atrial fibrillation (AF) ablation represents a paradigm shift in post-procedure care. This approach allows patients (pts) to return home on the same day after their ablation, promoting comfort and reducing hospitalization duration. Purpose To evaluate safety of same-day discharge in pts submitted to either pulsed field ablation (PFA) or cryoablation (CA). Methods Single-center retrospective study of AF pts submitted to ablation with either PFA or CA from May 2019 to November 2023. Ablation strategy consisted in pulmonary vein isolation complemented with ablation of the cavo-tricuspid isthmus in pts with history of atrial flutter. Pts were considered eligible to same-day discharge if an observation period of at least 6h was assured after the procedure. Safety was defined as 30-day major or minor complications. Chi-square tests were used for the comparison of continuous variables. Results We included 152 pts, 60 were submitted to PFA and 92 to CA, 56.6% males, median age 66±14 years, mean CHA2DS2-VASc score 2.45±1.4. Paroxysmal AF, short and long-standing persistent AF were present in 67%, 16% and 15% of pts respectively. Previous stroke was present in 8.7% of pts and 27 pts had history of heart failure. Acute success rate was 99.3%, concomitant cavo-tricuspid isthmus ablation was performed in 20% of pts, and mean procedure time was 107.5±74 min. Same-day discharge was initially considered in 70% of pts, however of these, 12 pts remained under further observation due to acute complications. No major or minor acute complications were reported in pts with same-day discharge. There were no significant differences in 30 days complications between groups. At 30 days no major complications were reported in pts with same-day discharge. One pts in which same-day discharge was halted died 4 days after ablation from hemorrhagic shock. Regarding minor complications at 30 days, 4 minor femoral hematoma were reported, 2 in each group. Conclusion In our population, same-day discharge proved to be a safe strategy if careful pts selection is assured. This practice enhances overall pt experience, marking a significant paradigm shift in AF management.

Comparative Efficacy of Cavotricuspid Isthmus Ablation in Sinus Rhythm Versus Typical Atrial Flutter

Background: Cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) is the most common atrial macro-reentrant tachycardia, characterized by a typical ECG pattern (type I ECG). Often, tachycardia terminates before it can be confirmed by an electrophysiological study (EPS), necessitating CTI ablation in sinus rhythm (SR). This study aims to compare the success rate of CTI ablation in patients with type I ECG during SR versus ongoing CTI-dependent AFL, focusing on arrhythmia recurrence. Methods: We screened patients at Ulm University Heart Center from January 2010 to November 2020 with type I ECG who underwent CTI ablation. Patients were divided into two groups: those whose tachycardia terminated before EPS and underwent ablation in SR, and those with ongoing CTI-dependent AFL during EPS. CTI ablation was deemed complete when a bidirectional conductance block was achieved, confirmed after 30 min. Results: A total of 230 patients were included, all showing typical AFL in ECG recordings. Of these, 67 patients underwent ablation in SR, while 163 were ablated during ongoing AFL. The median follow-up time was 2.7 years. Recurrence of CTI-dependent AFL occurred in 8.3% of patients: 4.5% in the SR ablation group and 9.8% in the ongoing AFL group. Kaplan–Meier estimation showed similar efficacy for both methods regarding arrhythmia recurrence (log-rank p = 0.07). Conclusions: Our decade-long study indicates that CTI ablation during SR is as effective as ablation during ongoing CTI-dependent AFL in achieving long-term freedom from arrhythmia. This research supports the efficacy of both techniques in clinical settings, validating a widely practiced approach.

Exploring Inflammatory Markers and Risk Factors Associated with Pericarditis Development after Ablation for Atrial Fibrillation.

Background: This study aimed to explore the association between inflammatory markers and the occurrence of post-atrial fibrillation (AF) ablation pericarditis (PAP), while also examining the PAP's incidence and contributing factors. Methods: A retrospective cohort study was conducted between January 2021 and November 2023, including patients who underwent successful AF ablation. Inflammatory markers of interest included the systemic immune-inflammation index (SII), the neutrophil-to-lymphocyte ratio (NLR), and the platelet-to-lymphocyte ratio (PLR). Results: Among the 231 patients examined, 22 (9.52%) were classified as suspected PAP, and 14 (6.06%) as definitive PAP. The median age was 58 years, with no age difference between groups. Males comprised 51.52% of the sample, with male sex frequency significantly higher in the suspected PAP group relative to the other groups (p = 0.007). Multivariable logistic regression indicated that AF duration (p = 0.026) and cavotricuspid isthmus (CTI) ablation (p = 0.001) were associated with definitive PAP, whereas analysis for any pericarditis (suspected or definitive PAP) revealed independent relationships with CTI ablation (p = 0.003) and sleep apnea (p = 0.008). SII, NLR, and PLR were not associated with PAP. Conclusions: Prolonged AF duration, CTI ablation, and sleep apnea are risk factors for PAP. The inflammatory markers (SII, NLR, and PLR) showed no association, warranting further investigation into other markers.

Cavotricuspid isthmus ablation using a pentaspline pulsed field ablation catheter: feasibility and acute results.

Cavotricuspid isthmus ablation using a pentaspline pulsed field ablation catheter: feasibility and acute results.

Long-term risk of right coronary artery injury after catheter ablation of cavotricuspid isthmus–dependent flutter

BackgroundRadiofrequency ablation (RFA) of cavotricuspid isthmus (CTI)–dependent atrial flutter requires ablation of the tricuspid annulus overlying the right coronary artery (RCA). Although it is considered safe, reports of acute and subacute RCA injury in human and animal studies raise the possibility of late RCA stenosis. ObjectiveThe objective of this study was to compare the incidence and severity of angiographic RCA stenoses in patients who have undergone CTI RFA with a control group to assess the long-term risk of RCA damage. MethodsA 2-center retrospective case-cohort study was performed including all patients from 2002 to 2018 undergoing atrial fibrillation (AF) with CTI ablation (CTI + AF) or AF ablation alone with subsequent coronary angiography (CAG). The AF alone group served as controls because of anticipated similarity of baseline characteristics. Coronary arteries that are anatomically remote to the CTI were examined as prespecified falsification end points. CAG was scored by a blinded observer. ResultsThere were 156 patients who underwent pulmonary vein isolation with subsequent CAG (CTI + AF, n = 81; AF alone, n = 75) with no difference in baseline characteristics including age, sex, comorbidities, and medications. Mean time from ablation to CAG was similar (CTI + AF, 5.0 ± 3.7 years; AF alone, 5.4 ± 3.9 years; P = .5). The mid and distal RCA showed no difference in the average number of angiographic stenoses or lesion severity. In regression analysis, CTI ablation was not a predictor of RCA stenosis severity (P = .6). There was no difference in coronary disease at sites remote to the CTI ablation (P = NS for all). ConclusionThere was no observed relationship between CTI RFA and the number or severity of angiographically apparent RCA stenoses in long-term follow-up.

Spanish catheter ablation registry. 23rd official report of the Heart Rhythm Association of the Spanish Society of Cardiology (2023)

Introduction and objectivesWe report the results of the 2023 Spanish catheter ablation registry. MethodsProcedural data were collected and incorporated into the REDCap platform by all participating centers through a specific form. ResultsThere were 104 participating centers in 2023 compared with 103 in 2022. In 2023, the total number of ablation procedures was 26 207, indicating a stabilization of the increase observed in 2022 following the pandemic. The increase was mainly due to procedures for atrial fibrillation (AF), with a total of 9942 ablations, representing 38% of all substrates. Notably, pulse-field ablation represented 10.3% of all AF ablation procedures, leading single-shot ablation strategies to outnumber point-by-point AF ablation for the first time in the history of the registry. Cavotricuspid isthmus ablation remained the second most targeted substrate (19% of all substrates, n=5067). The overall acute success rate remained high (97%), with a downward trend in the complication rate (1.6% vs 1.8% in 2022) and mortality rate (0.03%; n=7). Compared with 2022, there was a significant increase in procedures performed using electro-anatomical mapping and zero-fluoroscopy techniques for cavotricuspid isthmus ablation (52% vs 26%), AV node re-entrant tachycardia (48% vs 34%), and accessory pathways (62% vs 22%). We registered 466 ablations in pediatric patients. ConclusionsThe data indicate a stabilization in the post-pandemic increase in ablation procedures, with an absolute and relative increase in AF as the predominant substrate. Success rates remained stable with a modest reduction in complication and mortality rates.

Evaluation of risk factors for long-term atrial fibrillation development in patients undergoing typical atrial flutter ablation: amulticenter pilot study.

Atrial flutter (AFL) and atrial fibrillation (AF) are the most commonly detected supraventricular arrhythmias and share similar pathophysiological mechanisms. After the successful ablation of AFL, AF frequently occurs in the long-term follow-up. As emphasized in some studies, certain mechanisms seem to predispose to the development of AF in AFL patients, and approximately 20% of these patients have accompanying AFL. We aimed to analyze independent risk factors that predict the development of AF in patients who underwent typical AFL ablation. This was a multicenter, cross-sectional, and retrospective study. Atotal of 442 patients who underwent typical AFL ablation at three different centers between January1, 2018 and January1, 2022 were included retrospectively. After the ablation procedure the patients were divided into those who developed AF and those who did not. The patients were followed up for an average of 12(4-20) months. In the post-procedural period, atrial arrhythmias were investigated with 24‑h Holter and ECG at 1month, 6months, and 12months and then at 6‑month intervals thereafter. Overall, AF developed in 206 (46.6%) patients in the long-term follow-up. Age, hypertension (HT), obstructive sleep apnea syndrome (OSAS), previous cerebrovascular accident (CVA), left atrium anteroposterior diameter, severe mitral regurgitation, hemoglobin, blood glucose, and HbA1c values were found to be significant in univariable analysis. According to multivariable analysis, HT (p = 0.014; HR: 1.483 [1.084-2.030]), OSAS (p = 0.008; HR: 1.520 [1.117-2.068]) and previous CVA (p = 0.038; HR: 1.749 [1.031-2.968]) were independently associated with the development of AF in AFL patients who underwent ablation procedure. In the present study, we found that HT, OSAS, and previous CVA were independently correlated with the development of AF in the long-term follow-up of patients who underwent typical AFL ablation. We consider that AFL patients with such risk factors should be followed up closely following cavotricuspid isthmus ablation for the development of AF.

Registro español de ablación con catéter. XXIII informe oficial de la Asociación del Ritmo Cardiaco de la Sociedad Española de Cardiología (2023)

Introduction and objectivesWe report the results of the 2023 Spanish catheter ablation registry. MethodsProcedural data were collected and incorporated into the REDCap platform by all participating centers through a specific form. ResultsThere were 104 participating centers in 2023 compared with 103 in 2022. In 2023, the total number of ablation procedures was 26 207, indicating a stabilization of the increase observed in 2022 following the pandemic. The increase was mainly due to procedures for atrial fibrillation (AF), with a total of 9942 ablations, representing 38% of all substrates. Notably, pulse-field ablation represented 10.3% of all AF ablation procedures, leading single-shot ablation strategies to outnumber point-by-point AF ablation for the first time in the history of the registry. Cavotricuspid isthmus ablation remained the second most targeted substrate (19% of all substrates, n=5067). The overall acute success rate remained high (97%), with a downward trend in the complication rate (1.6% vs 1.8% in 2022) and mortality rate (0.03%; n=7). Compared with 2022, there was a significant increase in procedures performed using electro-anatomical mapping and zero-fluoroscopy techniques for cavotricuspid isthmus ablation (52% vs 26%), AV node re-entrant tachycardia (48% vs 34%), and accessory pathways (62% vs 22%). We registered 466 ablations in pediatric patients. ConclusionsThe data indicate a stabilization in the post-pandemic increase in ablation procedures, with an absolute and relative increase in AF as the predominant substrate. Success rates remained stable with a modest reduction in complication and mortality rates.

Efficacy and safety of a novel temperature-controlled catheter for cavotricuspid isthmus ablation.

Maintaining an adequate temperature at the target site is essential for effective ablation. We hypothesized that a tissue temperature-controlled (T-Con) catheter for cavotricuspid isthmus (CTI) ablation could improve the procedural ablation parameters. To evaluate the efficacy and safety of the T-Con (DiamondTemp™) catheter for CTI ablation compared with non-irrigation (Non-Irri) and irrigation (Irri) catheters. We analyzed 150 patients who underwent prophylactic CTI ablation combined with pulmonary vein isolation. The Non-Irri, Irri, and T-Con catheter groups comprised 50 patients each, and the ablation procedural parameters and complications were compared between these groups. There were no significant differences in clinical background characteristics among the three groups. The Kruskal-Wallis and post hoc tests demonstrated that the T-Con group showed the lowest total radiofrequency energy delivery time among the three groups (median [25 and 75 percentiles]: 340 [209, 357], 147 [100, 199], and 83 [61, 109] s, respectively in the Non-Irri, Irri, and T-Con groups; T-Con versus Non-Irri, p < .01; T-Con versus Irri, p < .01). The total procedural time and acute reconnection rate in the T-Con group (264 s and 4%, respectively) were lower than those in the Non-Irri group (438 s and 24%) but were similar to those in the Irri group (268 s and 6%). No significant complications were observed in any group. The T-Con catheter achieved a short energy delivery time and a low acute reconnection rate, indicating its potential as an alternative catheter for CTI ablation.

In Silico TRials guide optimal stratification of ATrIal FIbrillation patients to Catheter Ablation and pharmacological medicaTION: the i-STRATIFICATION study.

Patients with persistent atrial fibrillation (AF) experience 50% recurrence despite pulmonary vein isolation (PVI), and no consensus is established for secondary treatments. The aim of our i-STRATIFICATION study is to provide evidence for stratifying patients with AF recurrence after PVI to optimal pharmacological and ablation therapies, through in silico trials. A cohort of 800 virtual patients, with variability in atrial anatomy, electrophysiology, and tissue structure (low-voltage areas, LVAs), was developed and validated against clinical data from ionic currents to electrocardiogram. Virtual patients presenting AF post-PVI underwent 12 secondary treatments. Sustained AF developed in 522 virtual patients after PVI. Second ablation procedures involving left atrial ablation alone showed 55% efficacy, only succeeding in the small right atria (<60 mL). When additional cavo-tricuspid isthmus ablation was considered, Marshall-PLAN sufficed (66% efficacy) for the small left atria (<90 mL). For the bigger left atria, a more aggressive ablation approach was required, such as anterior mitral line (75% efficacy) or posterior wall isolation plus mitral isthmus ablation (77% efficacy). Virtual patients with LVAs greatly benefited from LVA ablation in the left and right atria (100% efficacy). Conversely, in the absence of LVAs, synergistic ablation and pharmacotherapy could terminate AF. In the absence of ablation, the patient's ionic current substrate modulated the response to antiarrhythmic drugs, being the inward currents critical for optimal stratification to amiodarone or vernakalant. In silico trials identify optimal strategies for AF treatment based on virtual patient characteristics, evidencing the power of human modelling and simulation as a clinical assisting tool.

Feasibility and procedural safety of the pentaspline pulsed field ablation catheter for atrial lesions beyond pulmonary vein isolation

Abstract Background The pentaspline multi-electrode pulsed-field ablation (PFA) catheter is widely used for the ablation of atrial fibrillation (AF). Given the favorable safety profile of PFA, lesions beyond pulmonary vein isolation (PVI) are increasingly performed. Purpose We aimed to assess the feasibility and safety of PFA beyond PVI with the pentaspline PFA catheter. Methods We retrospectively studied all patients who underwent PFA for atrial arrhythmias in our center between January and October 2023. Procedural characteristics and complications were compared between patients undergoing only PVI (PVI-only group) and those receiving extra-venous applications (extra-PVI group). Results We analysed 202 PFA cases. Indications for ablation included paroxysmal AF (34.7%), persistent AF (57.4%), long-standing persistent AF (5.9%) and atypical atrial flutter (2%). Redo procedures accounted for 18.8% of the total cases. PFA beyond PVI was performed in 142 (70.3%) patients. Patients in the extra-PVI group had a higher incidence of persistent AF (76.8% vs 11.7%, p&amp;lt;0.001), a higher BMI (29±5 vs 26±5 kg/m2, p=0.001) and a more dilated left atrium (LAVI: 73±24 vs 52±20 ml/m2, p&amp;lt;0.001, Table 1). PFA in this group consisted of PVI (98.6%), posterior wall isolation (PWI) (93%), mitral isthmus (MI) ablation (56.3%), a roof line (2.1%), ablation of dispersion electrograms (10.6%) and cavotricuspid isthmus (CTI) ablation (0.7%). In 22 (15.5%) patients, additional CTI ablation with radiofrequency (RF) was performed, while alcohol ablation of the vein of Marshall and RF ablation in the coronary sinus were required in 9 (6.3%) and 2 (1.4%) patients, respectively, to achieve MI block. Compared to the PVI-only group, PFA beyond PVI required a mean of 43 additional applications, a longer procedural (84±29 vs 65±22 min, p&amp;lt;0.001) and fluoroscopy time (25±10 vs 18±6 min, p&amp;lt;0.001) and had a higher fluoroscopy dose (24±35 vs 16.4±28.5 Gy.cm2, p=0.001). A three-dimensional electroanatomic map was used in 12% of cases. Acute success rates were 99% for PVI and PWI, 89% for MI ablation and 100% for roof lines and CTI ablation. Overall complication rates were similar in both groups (16.2% vs 13.3%, p=0.68, Table 2). One cardiac tamponade was observed in the extra-PVI group (0.7%) compared to 4 in the PVI-only group (6.7%, p=0.03). Among the latter, 2 incidents occurred during PVI in patients with long-standing persistent AF, precluding further extra-venous ablation. A small pericardial effusion (without hemodynamic compromise) and/or pericarditis were seen in 9.2% of patients in the extra-PVI group compared to 6.7% in the PVI-only group (p=0.78). No deaths occurred in either group. Conclusions Ablation beyond PVI with the pentaspline PFA catheter is feasible with high success rates and no apparent increase in procedural complications. However, it increases procedural duration and fluoroscopy. Notably, the majority of cardiac tamponades in this cohort occurred during PVI.

Pulsed-field ablation using a lattice-tip catheter without general anesthesia is feasible for atrial fibrillation ablation

Abstract Background General anesthesia (GA) was employed to titrate lesion formations for a pulsed-field ablation (PFA) using a lattice-tip catheter. The evidence using a lattice-tip catheter without the use of GA is limited. Purpose We conducted a series of exploratory evaluation of a lattice-tip PFA catheter ablation without GA. Methods Patients undergoing their first atrial fibrillation (AF) ablation procedures using a lattice-tip catheter were enrolled in the study. To assess acute outcomes and safety, the patients were divided into two groups: one undergoing the procedure with GA and the other without GA. Procedural characteristics were collected. Results In total, 20 patients (6 with GA, 14 without GA) were enrolled in the current study. One patient in non-GA group needed a larynx mask due to apnea from anesthesia. The pre-ablation 3D mapping time was equivalent between the two group (with GA versus without GA: 17±7 versus 16±5; P=0.762). All first-pass isolations of the pulmonary veins (PV) were successfully achieved, and there was no difference in the number of applications between the right and left PV (with GA versus without GA: 45±8 versus 53±12; P=0.206 and 47±14 versus 49±9; P=0.792). Linear lesions including anterior linear ablation (33% with GA and 36% without GA: P=1.000), roof linear ablation (67% with GA and 71% without GA: P=1.000) and cavo-tricuspid isthmus ablation (0% with GA and 7% without GA: P=1.000) were performed. The ablation, laboratory stay and fluoroscopy times were equivalent between the two group (with GA versus without GA:88±22 versus 97±20; P=0.483, 128±25 versus 111±18; P=0.216 and 9±4 versus 10±2; P=0.902), while the pre-ablation preparation times were shorter in the group without GA (with GA versus without GA:40±17 versus 14±4; P&amp;lt;0.01). There was no major and minor procedural complication in both groups. Conclusions The use of a lattice-tip catheter for ablation without GA has a potential to shorten the whole procedural work-flow including preparing time while maintaining comparable safety and lesion formation to cases where GA is utilized.

Low voltage area in the left atrial anterior wall predict Marshall-PLAN failure in patients with persistent atrial fibrillation

Abstract Background The most appropriate ablation strategy for persistent atrial fibrillation (PeAF) has not yet been determined. However, ethanol infusion of the vein of Marshall (VOM) combined with a linear set of ablation lesions (namely the Marshall-PLAN) has yielded encouraging results (1). Purpose Our study aimed at analyzing the relationship between low voltage areas (LVA) and arrhythmias recurrences in a PsAF population treated with the Marshall-PLAN. Methods we conducted a retrospective study on consecutive patients undergoing first catheter ablation (CA) for PsAF between 2021 and 2022 at our center. Pulmonary vein isolation (PVI), mitral isthmus ablation (VOM ethanol infusion, endocardial ablation and epicardial ablation in the great cardiac vein), left atrial (LA) roofline and cavo-tricuspid isthmus ablation were carried out in all the patients. Bidirectional block was validated for all the linear lesions as well as for PVI. Pre-ablation LA electroanatomic maps were built with CARTOv3 system and the PentaRay mapping catheter (minimum 3000 points). LVA were identified as areas &amp;gt;1cm2 (containing ≥3 neighboring points with ≤10mm distance) with bipolar voltage &amp;lt;0.5mV in SR and &amp;lt;0.24 mV in AF (2). All patients were followed for at least 12 months. Results Overall, 93 patients (69±7years, 30% female) with PsAF were included. Their left-ventricle ejection fraction and left atrial volume indexed for body surface area (LAVI) were 57% and 92±20 ml/m2. LA maps demonstrated at least one LVA in 70 subjects (75.3%). The mean relative surface of LA in which a LVA was evidenced was 8±14%. LVA were found within the anterior LA wall in 49 patients (53%), in the posterior wall in 33 patients (35.5%), in the inferior wall in 22 patients (24%), in the lateral wall in 14 patients (15.1%) and in the pulmonary vein region in 44 patients (47.3%). After 19±6 months of follow-up, 28 (30%) patients had AF recurrence. At Cox regression analysis (including LVA burden and LAVI dimensions), LVA localized within the anterior LA wall were predictive of arrhythmia recurrences (hazard ratio [HR] 2.0 [95% CI, 1.1–4.7], P=0.04). Kaplan-Meier estimates of survival free from recurrences at 20 months were 51% and 88% in patients with and without LVAs in the anterior LA wall (Log-rank 0.006). Conclusions The Marshall-PLAN led to a global AF-free survival of 70% after 19±6 months in our cohort of patients with PsAF. Importantly however, the data show that the subset of patients with LVA in the anterior LA wall (i.e., the LA region not targeted by the pre-specified ablation set here evaluated) have a 55%-only AF-free survival while that of patients without LVA in the anterior LA wall was of 88%. As a result, our study supports the relevance of atrial substrate assessment and the possibility of CA strategy optimization in the subset of patients with PsAF and LVA in the anterior LA wall (3).

Long-term success and predictors of atrial arrhythmia recurrence following left atrial flutter ablation

Abstract Background In recent years, success rate of left atrial flutter (LAFL) ablation has witnessed improvement, attributed to enhanced comprehension of the arrhythmia mechanism and technological advancements. However, the recurrence rate and specific types of atrial arrhythmias, along with their potential predictors, remain inadequately understood. Purpose The aim of this study is to assess the factors influencing the efficacy, safety, and long-term success of radiofrequency (RF) ablation for LAFL. Methods Patients with sustained LAFL undergoing RF ablation were included in the study. LAFL mapping employed a combination of activation, voltage, and entrainment with 3D electroanatomical mapping. RF ablation targeted a protected isthmus of slow conduction, and if not localized, it involved creating lines of conduction block transecting the reentrant circuit or empirically created lines. Ablation success was defined as clean arrhythmia termination during RF application and no LAFL induction with pacing maneuvers. Follow-up included outpatient visits at 6 and 12 months. Ablation success at follow-up was defined as the absence of arrhythmia recurrence (≥30s) at regular outpatient or emergency department visits. Clinical and electrophysiological characteristics were analyzed and correlated with ablation success, complications, and freedom from arrhythmia recurrences at follow-up. Results The study included 104 consecutive patients undergoing LAFL ablation (67.5 ± 11.3 years, 67% male). Clinical characteristics comprised 12 with HFrEF, 44 with structural heart disease, 25 with valvular heart disease, 43 with previous pulmonary vein isolation (PVI) ablation, and 39 with significant left atrium enlargement. Simultaneous cavotricuspid isthmus ablation (CTI) was performed in 46 patients. LAFL cycle length was 293±68 ms, with more than one LAFL mechanism (2.0±0.8 mechanisms) demonstrated in 76 patients (73%). The most common LAFL mechanism was perimetral reentry (37%). LAFL was successfully ablated 83% of cases, with 7 patients experiencing complications (4 tamponades and 3 sinus node dysfunctions following LAFL termination). At a median follow-up of 28 months, 35 patients (34%) had AFL recurrence, and 15 of them required a second ablation procedure. No factor was associated with LAFL recurrence, except for a short LAFL cycle length (P=0.04) at the ablation procedure. Demonstration of more than one LAFL mechanism (P=0.48) or LAFL termination by focal or linear RF application (P=0.99) were not associated with AFL recurrences at follow-up. Conclusions Despite the relatively high efficacy of LAFL ablation, the rate of atrial arrhythmia recurrences at follow-up after a single procedure remains elevated, predominantly in the form of AFL rather than AF. Short LAFL cycle length at the index procedure appears to be a significant predictor of these recurrences. Arrythmia cycle length proved to be predictive factor of LAFL ablation success rate.Peri-veinal left AFL, LAT map, CranialPeri-veinal left AFL, LAT map, PA