Ablation Of Typical Atrial Flutter Research Articles

Ten-year follow-up results of patients with persistent atrial fibrillation treated by combined pulmonary vein isolation and complex fractionated atrial electrocardiogram ablation

Abstract Background For persistent atrial fibrillation (AF), pulmonary vein isolation (PVI) alone is associated with lower success rate compared to paroxysmal AF and additional strategies are needed. Ablation targeting on complex fractionated atrial electrograms (CFAE) is an alternative method. Although clinical benefits of the strategy combined PVI and CFAE ablation have not been shown by large trials, clinical situations and consequences of this approach have not been clearly demonstrated during very long term follow-up. Purpose This study aimed to retrospectively investigate clinical outcomes of patients with persistent AF treated by the approach combined PVI and CFAE ablation during a follow-up period of 10 years. Methods 73 patients (59.4±8.1 years, 64 male, AF history 5.5 years) with persistent (23, 31.5%) and long-standing persistent AF (50, 68.5%) who underwent combined PVI and CFAE ablation in the first procedure were included. Structural heart disease was found in 9 patients, and a history of ablation for typical atrial flutter (AFL) in 4. A complete CFAE mapping in the left atrium and coronary sinus was performed with a 3-D mapping system (EnSite NavX). All CFAEs defined as electrograms with continuous activities or mean cycle length detected by the system <80 ms were eliminated. All patients were controlled regularly during the first year with 12-lead ECG and Holter monitoring and followed by annual control. The electronic health records for all patients were extensively investigated and the patients were interviewed in 2020-2022. Any documented atrial tachyarrhythmia (ATA) after 3-month blanking period was regarded as recurrence. Results Mean 2.2±1.2 (1-5) ablation procedures were performed in each patient. After index ablation, 18 (24.7%) were free of ATAs during 10-year follow-up. 26 (35.6%) had recurrence of only AF, 6 (8.2%) of only AFL and 23 (31.5%) had both AF and AFL. The proportion of AFL was 39.7% with 6 typical AFL. After multiple ablation procedures, 33 (45.2%) patients were free of ATA during the follow-up. 23 (31.5%) had recurrence of only AF, 5 (6.8%) of only AFL and 12 (16.4%) of both AF and AFL. The proportion of AFL was 23.2% with no typical AFL. At 1-year follow-up, freedom of ATAs in persistent AF was higher than that in long-standing AF (65.2 vs. 40.0%, p=0.033) and no significant difference was found after 2 years (47.8 vs. 34.0%, p=0.129) until 10 years (30.4 vs. 22.0%, p=0.167, Figure 1). No difference was observed between these subgroups after multiple procedures at 10-year follow-up (47.8 vs. 44.0%, p=0.708, Figure 2). Conclusions PVI plus CAFE ablation in patients with persistent AF led to a high recurrence of ATA after index ablation. Difference of ATA-freedom between persistent and long-standing persistent AF groups was found only 1 year after the index procedure, but not during further follow-up. Incidence of post-ablation AFL was particularly high, even after multiple ablation procedures.Figure 1Figure 2

Optimizing outcomes in catheter ablation for typical atrial flutter: a comparative study of intracardiac echocardiography versus fluoroscopy guidance

Abstract Background Catheter ablation is a standard intervention for typical atrial flutters, specifically targeting the cavotricuspidal isthmus (CTI). Intracardiac echocardiography (ICE) plays a pivotal role in providing real-time visualization of anatomical structures during the electrophysiology procedure, thereby enhancing safety and potentially reducing reliance on fluoroscopy, leading to improved procedural outcomes. We aimed to conduct a comparative analysis of procedural and follow-up outcomes between ICE-guided and fluoroscopy-only guided catheter ablations for CTI in patients undergoing treatment for typical atrial flutter. Methods A retrospective analysis was conducted at our university center, encompassing 376 consecutive patients in a single-center study. Of these, 158 underwent procedures guided solely by fluoroscopy, while 218 received ICE-guided CTI ablation. Results ICE-guidance demonstrated a statistically significant reduction in fluoroscopy time (72 [36; 170] s vs. 888 [578; 1184] s; p<0.01), total procedure time (70 [52; 90] min vs. 90 [60; 105] min; p<0.01), total ablation time (692 [435; 998] s vs. 920 [629; 1373] s; p<0.01), and the duration from the first to last ablation (20.5 [12; 37] min vs. 41.0 [26.8; 59.3] min; p<0.01). Both groups achieved a 100% acute success rate without major complications. The ICE-guided group exhibited a significantly superior long-term success rate (ICE-guided group: 95.74%, fluoroscopy-only group: 89.26%; p=0.048) compared to the fluoroscopy-only group at an average follow-up length of 34 months. Conclusion The utilization of ICE-guidance for CTI ablation significantly reduces fluoroscopy exposure, procedure time, and ablation time, ultimately contributing to enhanced long-term success rates when compared to the conventional fluoroscopy-only approach.

Validation of bidirectional cavotricuspid isthmus block using electrocardiographic imaging

Abstract Background The validation of bidirectional cavotricuspid isthmus (CTI) block following catheter ablation for typical atrial flutter (AFL) involves endocavitary manoeuvres using multiple catheters. The diagnostic capacity of electrocardiographic imaging (ECGi) as a non-invasive tool to confirm bidirectional CTI block may simplify the procedure but its benefit has not been investigated so far. Purpose To evaluate the diagnostic capacities of a novel imageless ECGi system in detecting bidirectional CTI block during AFL catheter ablation. Methods A total of 34 patients were consecutively included in a prospective single-centre study. Atrial activation maps were derived from a novel imageless ECGi system when pacing the septal and lateral aspects of the CTI, gauging the technology's capacities to detect bidirectional block by measuring transisthmic intervals (TII) and observing wave-front collision patterns. TII reflects the time taken for electrical activation to cross the CTI during pacing and we measured both the absolute value and the increase relative to its baseline value. The bidirectional CTI block was assessed by endocavitary manoeuvres using a multipole catheter as the gold-standard. We conducted a blind assessment of the diagnostic capacities of ECGi over endocavitary manoeuvres considering maps from the septal and lateral pacing to determine clockwise and counterclockwise CTI block, respectively. Results Our study established clear benchmarks for diagnosing CTI block using ECGi (Figure 1). Regarding the assessment of clockwise CTI block, the presence of a wave-front collision pattern at the CTI yielded a positive predictive value (PPV) of 91% and negative predictive value (NPV) of 69%. Furthermore, ROC analysis pinpointed 100 ms and 30 ms as the optimal threshold for TII absolute value (PPV=89%, NPV =78%) and TII increase from baseline (PPV=91%, NPV =65%), respectively. Taking together, the combination of these three parameters offered high diagnostic capacities (PPV=87%, NPV=90%). Regarding counterclockwise CTI block, the TII absolute value alone was a reliable predictor, with a threshold derived from ROC analysis of 115 ms providing a PPV of 77% and a NPV of 83% (Graphical abstract). Conclusion These results highlight the efficacy of ECGi in CTI block assessment, promising a streamlined and accurate diagnostic approach (Graphical abstract). The use of a single ablation catheter coupled with ECGi to assess the bidirectional CTI block offers a simplified and efficient alternative to traditional dual catheter techniques.ECGi-based CTI block assessment methodGraphical abstract

Using the impedance map to identify non-conductive structures during cavo-tricuspidal isthmus ablation

Abstract Background The ablation of the cavo-tricuspidal isthmus (CTI) is often affected by the anatomical variability of structures made of non-conductive tissue (NCS): the Eustachian valve, tricuspid valve leaflet and Tebesio's valve, the presence of which may be associated with failure of the isthmic block despite a large number of erogations and post-ablation recurrences. Since these structures have different conductive properties from atrial tissue, it is plausible that they are characterised by their own tissue impedance, and can therefore be identified through an impedance map. Objectives The objectives of the study were: 1) to characterise CTI by impedance map, in order to identify NCS; 2) to perform ablation of CTI aimed at isolating only conductive tissue by combining impedance map with the Maximum Voltage Gradient (MVG) technique, in order to evaluate the efficacy of this strategy in acute and during follow-up. Methods From 01/2021 to 09/2023 impedance map and CTI substrate map was performed, without the use of fluoroscopy, in all patients undergoing ablation of typical atrial flutter. A 15-ohm impedance reduction from the mean atrial impedance was considered the cut-off for defining the presence of NCS. Substrate maps were constructed according to the MVG technique (0.5-2.5 mV thresholds), in particular looking for high-voltage channels in which the impedance map detected the presence of NCS. Ablation was performed only in the high-voltage channels (W45, AI500). Results Our study included 48 patients with a mean age of 68±13 years, with 92% of them being men. The mean volume of the right atrium was 153 mL, and the mean number of points per map was 1205. With the use of impedence map, we were able to identify the presence of NCS in 25 patients (52%). The distribution of non conductive structures and the mean voltage by quadrants can be seen in Figures B-C. Importantly, we found that the mean number of radiofrequency applications required to achieve isthmic block was significantly lower in patients with identified NCS compared to those without (6.3 vs. 10; p=0.007). In 60% of the patients with NCS, radiofrequency was administered in high-voltage channels that were detected in the quadrant where the NCS was present (odds ratio 3.42, p=0.04). Furthermore, we successfully achieved acute isthmic blockade in all patients, and there were no instances of recurrence during a mean follow-up period of 186 days. Conclusions Our findings demonstrate that the combination of Impedence Map and the Maximum Voltage Gradient technique is an effective approach for achieving isthmic block with a reduced number of radiofrequency applications. The identification of NCS allows for a more precise search for high-voltage channels, enabling ablations to be performed in optimal contact with the tissue. This meticulous approach is crucial for the success of the procedure.

PROMINENT CRISTA TERMINALIS AND ATRIAL FLUTTER: CASE REPORT

Abstract Introduction Crista terminalis is a fibromuscular ridge at the posterolateral region of the right atrium (RA). Prominent crista terminalis can mimic pathologic RA mass on transthoracic echocardiograms. Transesophageal echocardiography can be used to differentiate non pathologic structures from pathologic ones. Case Report A 51–year–old men was referred to our clinic with typical atrial flutter. Transthoracic echocardiogram (TTE) revealed a RA mass. It was round, 15 mm in diameter, immobile, not calcified, and located at the posterior region of RA. Transesophageal echocardiography (TEE) showed prominent crista terminalis superiorly located beneath superior vena cava in the RA at 91 degrees midesophageal position. The patient undergoes catheter ablation for typical atrial flutter. Discussion Several congenital structures and normal variants such as Chiari’s network, eustachian and thebesian valves, and atrial septal aneurysms may simulate pathologic RA masses such as RA thrombus or myxomas. However, in this case, an anatomical variant is associated with an arrhythmia that requires treatment. Conclusion In this case we want to emphasize that prominent crista terminalis can mimic RA mass and may lead to atrial arrhythmias. TEE can be used to differentiate normal structures from pathologic.

Development and Validation of the Atri-Risk Conduction Index Risk Score to Predict Risk of Atrial Fibrillation After Typical Atrial Flutter Ablation.

Identification of patients at risk for atrial fibrillation (AF) after typical atrial flutter ablation (tAFl) is important to guide monitoring and treatment. To create and validate a risk score to predict AF after tAFl ablation METHODS: We identified patients who underwent tAFL ablation with no AF history between 2017-2022 and randomly allocated to derivation and validation cohorts. We collected clinical variables and measured conduction parameters in sinus rhythm on an electrophysiology recording system (CardioLab, GE Healthcare). Univariate and multivariate logistic regressions (LogR) were used to evaluate association with AF development. 242 consecutive patients (81% males, mean age 66+/-11) were divided into derivation and validation cohorts, (n=142 and n=100). 42% developed AF over a median follow up of 330 days. In multivariate LogR (derivation cohort) , proximal to distal coronary sinus time (pCS-dCS) ≥70ms (OR 16.7 CI 5.6-49), pCS time≥36ms (OR 4.5 CI 1.5-13), and CHADS2VASc≥3 (OR 4.3 CI 1.6-11.8) were independently associated with new AF in follow-up. The Atri-Risk Conduction Index (ARCI) score was created with 0 as minimal and 4 as high-risk using pCS-dCS ≥70ms =2 points, pCS≥36ms=1 point, and CHADS2VASC≥3=1point. In the validation cohort, 0% of patients with ARCI score of 0 developed AF while 89% of patients with ARCI score of 4 developed AF. We developed and validated a risk-score using atrial conduction parameters and clinical risk factors to predict AF after tAFl ablation. It stratifies low, moderate, and high-risk patients and may be helpful in individualizing approaches to AF monitoring and anticoagulation.

The Effect of the Use of Activation 3D Mapping on the Patient X-Ray Load During Radiofrequency Ablation of Typical Atrial Flutter

Supraventricular macro re-entry tachyarrhythmias occupy the leading places among all types of tachyarrhythmias. The most common in this category is typical atrial flutter (AFL). This heart rhythm disorder has a negative impact on the patients’ quality of life. Its complications can lead to disability and death due to possible thromboembolism. Therapeutic treatment is limited in effectiveness. The main method of intervention is catheter radiofrequency ablation (RFA). The standard approach of RFA of AFL is performed without the use of navigation systems under fluoroscopy guidance. However, this results in an increased radiation exposure to the patient and the medical personnel. Modern technologies in the field of invasive electrophysiology make it possible to create anatomical models of heart and reproduce the spread of electrical excitation. However, the routine use of additional navigation methods remains controversial.
 The aim. To compare the duration of RFA of typical AFL and radiation exposure with the use of anatomical and propagation mapping.
 Materials and methods. This study is based on the analysis of the treatment results obtained for 53 patients at the National Amosov Institute of Cardiovascular Surgery in the period from 2014 to 2023. Depending on imaging methods, the patients were divided into two groups. The first group included 27 patients with an anatomical mapping of the right atrium. The second group included 26 patients with propagation mapping.
 Results. In all the patients we have achieved a bidirectional conduction block through cavotricuspid isthmus. In the first group, the total duration of confirming the diagnosis and creating the anatomical model was 312 ± 26 seconds. The mean time to the moment of AFL termination and restoration of sinus rhythm was 230 ± 19 seconds. The average duration of the procedure was 41.5 ± 3.5 minutes, the average fluoroscopy time was 120 ± 10 seconds, the average dose area product (DAP) was 15 ± 1.3 Gy·cm2. In the second group, the average time for creating a 3D propagation model of right atrium and verifying the diagnosis was 748 ± 65 seconds. The average time from the first application to the termination of tachycardia was 227 ± 20 seconds. The average duration of the procedure was 55 ± 4.7 minutes, X-ray time was 93 ± 8 seconds, average DAP was 13 ± 1.1 Gy·cm2. The duration of the procedure in the second group was significantly longer (p = 0.03), however, the radiation exposure and DAP were not statistically different (p = 0.31) between the observation groups.
 Conclusions. The use of propagation mapping increases the time of the procedure by 24.5% and does not give a significant advantage in reducing the radiation exposure. The use of a navigation system during cavotricuspid isthmus RFA is recommended for concomitant radical treatment of complex supraventricular arrhythmias, such as atrial fibrillation.

A Simple Score to Predict New-onset Atrial Fibrillation After Ablation of Typical Atrial Flutter

New-onset atrial fibrillation (NeAF) is common after cavotricuspid isthmus-dependent counterclockwise atrial flutter (CCW-AFL) ablation. This study aimed to investigate a simple predictive model of NeAF after CCW-AFL ablation. From January 2013 to December 2017, consecutive patients receiving CCW-AFL ablation were enrolled from three centers. Clinical, echocardiographic, and electrocardiographic data were collected and followed. Patients from two centers and another center were assigned into the derivation and validation cohorts, respectively. In the derivation cohort, logistic regression was performed to evaluate the ability of parameters to discriminate those with and without NeAF. A score system was developed and then validated. Two hundred seventy-one patients (mean 59.7±13.6 age; 205 male) were analyzed. During follow-up (73.0±6.5 months), 107 patients (39.5%) had NeAF. 190 and 81 patients were detected in the derivation and validation cohorts, respectively. Hypertension, age ≥70 years, left atrial diameter ≥42 mm, P wave duration ≥120 ms and the negative component of flutter wave in lead II ≥120 ms were selected as the final parameters. A weighted score was used to develop the HAD-AF score ranging from 0 to 9. In the derivation cohort, area under the receiver operating characteristic curve (AUC) was 0.938 (95% CI 0.902-0.974), superior to those of currently used CHA2DS2-VASC (0.679, 95% CI 0.600-0.757) and HATCH scores (0.651, 95% CI 0.571-0.730) (P<0.001). Performance maintained in the validation cohort. 39.5% of patients developed NeAF in 6 years after CCW-AFL ablation. HAD-AF score can reliably identify patients likely to develop NeAF after CCW-AFL ablation.

Navigating the risk of atrial fibrillation after successful ablation of lone typical atrial flutter.

Navigating the risk of atrial fibrillation after successful ablation of lone typical atrial flutter.

Identification of cavotricuspid isthmus voltage patterns in typical atrial flutter ablation

AbstractBackgroundElectroanatomical mapping is an essential tool in the ablation of typical AFL.ObjectivesTo identify the existence of voltage patterns in the CTI voltage maps and their relevance for typical AFL ablation.MethodsA voltage map of the CTI was made prior to ablation, identifying the areas of maximum voltage and their location along the CTI, allowing classification into patterns according to their distribution. A stepwise ablation approach targeting the areas of maximum voltage was conducted. The ablation characteristics were compared based on the pattern obtained.ResultsTwo voltage patterns were identified, with differences in ablation time to bidirectional CTI block. No complications occurred.ConclusionsVoltage mapping identifies patterns in the CTI with implications for typical AFL ablation.

Association of typical atrial flutter and cavotricuspid isthmus ablation on clinical recurrence after cryoballoon ablation for atrial fibrillation.

Typical atrial flutter commonly occurs in patients with atrial fibrillation (AF). Limited information exists regarding the effects of concurrent atrial flutter on the long-term outcomes of rhythm control. This study investigated the association between concurrent typical atrial flutter and cavotricuspid isthmus (CTI) ablation and the recurrence of atrial arrhythmia. The data were obtained from a multicenter registry of cryoballoon ablation for AF (n = 2,689). Patients who were screened for typical atrial flutter were included in the analysis (n = 1,907). All the patients with typical atrial flutter underwent CTI ablation. The primary endpoint was the late recurrence of atrial arrhythmia, including AF, atrial flutter, and atrial tachycardia. Among the 1,907 patients, typical atrial flutter was detected in 493 patients (25.9%). Patients with concurrent atrial flutter had a lower incidence of persistent AF and a smaller size of the left atrium. Patients with atrial flutter had a significantly lower recurrence rate of atrial arrhythmia (19.7% vs. 29.9%, p < 0.001). In patients with atrial flutter, the recurrence rate of atrial tachycardia or atrial flutter was more frequent (7.3% vs. 4.7%, p = 0.028), but the recurrence rate of AF was significantly lower (17.0% vs. 29.4%, p < 0.001). Atrial flutter has been identified as an independent predictor of the primary endpoint (adjusted hazard ratio, 0.704; 95% confidence interval, 0.548-0.906; p = 0.006). Typical atrial flutter in patients with AF may serve as a positive marker of the recurrence of atrial arrhythmia, and performing CTI ablation in this population is associated with a reduced likelihood of AF recurrence. Performing routine screening and ablation procedures for coexisting atrial flutter may improve the clinical outcomes of AF.

Catheter ablation of typical right atrial flutter in a 20‐day‐old neonate with tachycardiomyopathy

AbstractBackgroundFetal echocardiography can diagnose neonatal atrial flutter, which can cause heart failure in newborns. Little is known about catheter ablation in this population.MethodsCase report that aimed to review a successful ablation in a 20‐day‐old patient with refractory atrial flutter.ResultsThis is the first report of a successful neonatal atrial flutter ablation without any early recurrence after the procedure.ConclusionsAtrial flutter ablation performed on newborns is a reliable and long‐lasting treatment option.

Catheter ablation of typical atrial flutter improves cardiac chamber size and function.

Cavo-tricuspid isthmus (CTI) dependent atrial flutter (AFL) is one of the most common atrial arrhythmias involving the right atrium (RA) for which radiofrequency catheter ablation has been widely used as a therapy of choice. However, there is limited data on the effect of this intervention on cardiac size and function. A retrospective study was conducted on 468 patients who underwent ablation for CTI dependent typical AFL at a single institution between 2010 and 2019. After excluding patients with congenital or rheumatic heart disease, heart transplant recipients, or those without baseline echocardiogram, a total of 130 patients were included in the analysis. Echocardiographic data were analyzed at baseline before ablation, and at early follow-up within 1-year postablation. Follow-up echocardiographic data was available for 55 patients. Of the 55 patients with CTI-AFL, the mean age was 64.2 ± 14.8 years old with 14.5% (n = 8) female. The average left ventricular ejection fraction (LVEF) significantly improved on follow-up echo (40.2 ± 16.9 to 50.4 ± 14.9%, p < .0001), of which 50% of patients had an improvement in LVEF of at least 10%. There was a significant reduction in left atrial volume index (82.74 ± 28.5 to 72.96 ± 28 mL/m2 , p = .008) and RA volume index (70.62 ± 25.6 to 64.15 ± 31 mL/m2 , p = .046), and a significant improvement in left atrial reservoir strain (13.04 ± 6.8 to 19.10 ± 7.7, p < .0001). Patients who underwent CTI dependent AFL ablation showed an improvement in cardiac size and function at follow-up evaluation. While long-term results are still unknown, these findings indicate that restoration of sinus rhythm in patients with typical AFL is associated with improvement in atrial size and left ventricular function.

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

Abstract Background/Introduction Atrial flutter (AFL) and atrial fibrillation (AF) are the most commonly detected supraventricular arrhythmia and share similar pathophysiological mechanisms (1). After the successful ablation of AFL, AF frequently occurs in such patients in the long-term follow up (2). As emphasized in some studies, some mechanisms seem to predispose to the development of AF in AFL patients and approximately 20% of such kind of patients have accompanying AFL (3). Purpose We aim to analyze independent risk factors that predict the development of AF in patients who underwent typical AFL ablation. Methods Our study was designed as multi-center, cross-sectional and retrospective. A total of 442 patients who underwent typical AFL ablation at 3 different centers between January 1, 2018 and January 1, 2022 were included retrospectively. The patients after the ablation procedure 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-procedure period, atrial arrhythmias were investigated with 24-hour Holter and ECG at 1st month, 6th month, 12th month and at 6-month intervals thereafter. Results 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 antero-posterior 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. Conclusion 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 cavo-tricuspid isthmus ablation for the development of AF. Univariable and Multivariable Analyzes Kaplan - Meier Curves

Abstract 16484: Utility of Steerable Sheaths and Intracardiac Echocardiography for Typical Atrial Flutter Ablation

Introduction: Sheaths (SS) and intracardiac echocardiography (ICE) are being increasingly utilized to improve safety, efficacy, and efficiency of catheter ablation procedures for different arrhythmias. The utility of these tools to guide ablation of typical atrial flutter (AFL) are not well characterized. Hypothesis: The use of SS plus ICE during typical AFL ablation leads to improved procedural and long-term outcomes as well as shorter procedural, fluoroscopy, and total radiofrequency times. Methods: In this retrospective chart review, medical records were abstracted for patients undergoing typical AFL ablation alone between 7/2019-5/2023. Demographics, medical history, and baseline procedural data were collected. Procedural outcomes were achievement of bidirectional block and complications. Long term outcome was recurrence of typical AFL or unblocked cavotricuspid isthmus (CTI) at repeat ablation (for any arrhythmia). Data analyzed with intention-to-treat analysis. Results: 197 patients were identified. The use of SS plus ICE had the shortest procedural time (69.81 ± 34.49 mins, p&lt;0.001), total radiofrequency time (362.91 ± 502.62 secs, p=0.005), and fluoroscopy time (5.28 ± 3.34 mins, p&lt;0.001) (Figure 1). When patients were divided based on SS alone, both procedural and radiofrequency times were shorter with the use of SS vs no SS (81.04 ± 40.37 vs 91.74 ± 37.67 mins, p&lt;0.001; 370.02 ± 460.44 vs 602.27 ± 592.28 secs, p=0.001), however, fluoroscopy time was longer (8.25 ± 7.75 vs 6.60 ± 5.58 mins, p&lt;0.001). There was no difference between acute procedural success rates. Those in SS group were less likely to have recurrent typical AFL or unblocked CTI on redo ablation (0 out of 49 [0%] vs 6 out of 148 [4%]). Conclusion: Typical AFL ablation using SS plus ICE resulted in shorter procedural, total radiofrequency, and fluoroscopy times with similar acute procedural success rates. The use of SS (regardless of ICE) is associated with increased long-term success rate.

Abstract 17847: Typical Right Atrial Flutter Ablation Using Subclavian Venous Access in Patients With Interrupted or Occluded Inferior Vena Cava

Introduction: Ablation for typical atrial flutter (AFL) traditionally involves vascular access from the femoral vein to facilitate advancing catheters through the Inferior Vena Cava (IVC) to the right atrium (RA). In patients with interrupted or occluded IVC, this procedure is challenging to perform. We report a case series of typical right AFL ablation using subclavian access in interrupted or occluded IVC. Cases: A 63-year-old female with typical AFL refractory to medical therapy was referred for radiofrequency ablation (RFA). She had a history of surgically corrected atrial septal defect at age 4 years with known IVC interruption draining into RA via an azygous venous extension. Another case involved a 41-year-old male with quadriplegia and typical AFL who underwent an attempted RFA from femoral access that was aborted due to massive thrombosis of IVC. Decision making: In both cases, two sheaths were placed into the left subclavian venous system using ultrasound guidance. A coronary sinus catheter and irrigated tip ablation catheter were advanced into the coronary sinus and RA respectively. Additionally, in the second case, an intracardiac echocardiography probe was inserted via separate venous access. Using the electroanatomic mapping system, entrainment and activation mapping confirmed a tricuspid isthmus-dependent AFL. RFA was performed using an open irrigated RFA catheter in a linear fashion resulting in the termination of the tachycardia to sinus rhythm. In the first case, ablation extended from the tricuspid annulus to the os of the hepatic vein at the 06:00 position. Post ablation, hemostasis was achieved using a suture-mediated closure device. At follow-up, both patients were asymptomatic without evidence of AFL on extended-duration cardiac monitoring. Conclusion: In patients with interrupted or occluded IVC, the subclavian veins can be accessed for mapping and ablation of typical AFL when traditional femoral venous access is challenging.

Safety and effectiveness of the first contact force ablation catheter with a flexible tip

Catheter ablation is an established therapy for paroxysmal atrial fibrillation (PAF). The TactiFlex Ablation Catheter, Sensor Enabled (TactiFlex SE) is a next-generation radiofrequency ablation catheter incorporating fiber optics-based contact force-sensing technology with a flexible, laser-cut tip. The study sought to evaluate the safety and effectiveness of the TactiFlex SE ablation catheter for treatment of drug-refractory PAF. The TactiFlex AF investigational device exemption was a prospective, nonrandomized, multicenter clinical study. Enrollment began on June 26, 2020 and completed June 18, 2021. Subjects with PAF underwent de novo pulmonary vein isolation and, if indicated, ablation for typical atrial flutter. Subjects were followed for 12 months. Of the 355 subjects enrolled at 37 sites worldwide, 334 underwent ablation with the TactiFlex SE catheter. The Kaplan-Meier estimate of 12-month freedom from AF/atrial flutter (AFL)/atrial tachycardia recurrence was 72.9% (95% confidence interval [CI] 95% CI 67.2%-77.8%) and clinical success was 83.6% (95% CI 95% CI 78.1%-87.2%). As-treated analyses compared subjects treated at high power (left atrium time-averaged power setting 40-50 W; n = 222) vs low power (<40 W; n = 97). The Kaplan-Meier estimate of 12-month freedom from AF/AFL/atrial tachycardia recurrence was 76.4% (95% CI 69.3%-82.0%) and clinical success was 83.9% (95% CI 77.5%-88.6%) in the high-power group compared with 66.8% (95% CI 56.1%-75.5%) and 80.7% (95% CI 70.8%- 87.5%), respectively, in the low-power group. The primary safety event rate in all treated subjects was 4.3%; 4.1% in the HP group and 5.2% in the LP group (P = .7671). TactiFlex SE is safe and effective for treatment of drug-refractory PAF and concomitant AFL and enables more efficient procedures than previous generation catheters.

Comparative Effectiveness of Various Radiofrequency Ablation Catheters in the Ablation of Typical Atrial Flutter.

Although ablation of typical atrial flutter (AFL) can be easily achieved with radiofrequency energy (RF), no studies compare the effectiveness of different ablation catheters. Our study aimed to compare the efficacy of various types of ablation catheters in treating typical AFL. We analyzed patients with AFL who underwent RF ablation by a single operator at our institution. Successful ablation was evidenced by a bidirectional conduction block (trans-isthmus conduction time ≥ 130ms or double potentials ≥ 90ms). Logistic regression was used to compare success rate and linear regression to compare lesion time. Out of 222 patients, only six did not meet the success criteria (2.7%). The catheters used were non-irrigated, large-tip, internally irrigated (Chili II Boston Scientific), and externally irrigated (non-force-sensing) catheters (Cool Path, Abbott). An externally irrigated force-sensing catheter (TactiCath, Abbott) was used with > 10 gm of force and (LPLD) setting (30 W- 45°C- 60s), and high-power short-duration (HPSD) setting (50 W- 43°C - 12s). No complications were encountered. The catheter type had no statistically significant association with ablation success. With the use of externally irrigated catheter with contract force-sensing and HPSD settings, statistically significantly shortening of lesion time was achieved 758.3s, [CI - 1128.29, - 388.35s] followed by LPLD by 419.0s [CI - 808.49, - 29.47s]. The typical atrial flutter radiofrequency ablation procedure had a high success rate, which was not influenced by the type of ablation catheter. Contact force ablation catheter and HPSD are associated with shorter total lesion time.

Intracardiac Echocardiography Guidance Improves Procedural Outcomes in Patients Undergoing Cavotricuspidal Isthmus Ablation for Typical Atrial Flutter.

Atrial flutter (AFL) represents a prevalent variant of supraventricular tachycardia, distinguished by a macro-reentrant pathway encompassing the cavotricuspid isthmus (CTI). Radiofrequency (RF) catheter ablation stands as the favored therapeutic modality for managing recurring CTI-dependent AFL. Intracardiac echocardiography (ICE) has been proposed as a method to reduce radiation exposure during CTI ablation. This study aims to comprehensively compare procedural parameters between ICE-guided CTI ablation and fluoroscopy-only procedures. A total of 370 consecutive patients were enrolled in our single-center retrospective study. In 151 patients, procedures were performed using fluoroscopy guidance only, while 219 patients underwent ICE-guided CTI ablation. ICE guidance significantly reduced fluoroscopy time (73 (36; 175) s vs. 900 (566; 1179) s; p < 0.001), fluoroscopy dose (2.45 (0.6; 5.1) mGy vs. 40.5 (25.7; 62.9) mGy; p < 0.001), and total procedure time (70 (52; 90) min vs. 87.5 (60; 102.5) min; p < 0.001). Total ablation time (657 (412; 981) s vs. 910 (616; 1367) s; p < 0.001) and the time from the first to last ablation (20 (11; 36) min vs. 40 (25; 55) min; p < 0.01) were also significantly shorter in the ICE-guided group. Acute success rate was 100% in both groups, and no major complications occurred in either group. ICE-guided CTI ablation in patients with AFL resulted in shorter procedure times, reduced fluoroscopy exposure, and decreased ablation times, compared to the standard fluoroscopy-only approach.

Half-Normal Saline vs Normal Saline for Cavotricuspid Isthmus-Dependent Atrial Flutter Ablation

BackgroundCavotricuspid isthmus (CTI) ablation requires permanent bidirectional block to prevent recurrence of typical atrial flutter (AFL). Catheter irrigation with half-normal saline (HNS) produces larger and deeper lesions in experimental models compared with normal saline (NS). This study was performed to compare the clinical efficacy and safety of HNS vs NS irrigation for typical AFL ablation. MethodsSixty patients undergoing catheter ablation of typical AFL were randomized 1:1 to NS or HNS irrigation. Endpoints included time to CTI block, acute reconnection, incidence of steam pops, and recurrence of AFL during follow-up. ResultsBaseline characteristics were comparable between both arms. The mean age of the patients was 68.5 ± 8.2 years, 20% were female, and 32% had atrial fibrillation before being enrolled. Bidirectional CTI block was obtained in all patients with no difference in time to CTI block between groups (6.4 ± 4.4 minutes vs 7.6 ± 4.5 minutes, respectively; P = 0.15). There was a trend to less acute reconnection in the HNS group compared with NS (13.3% vs 26.6%; P = 0.46). Steam pops occurred in 4 patients using HNS vs none in the NS group, but no major complications were observed. During the follow-up, rate of AFL recurrence was similar between groups (6.7% with HNS vs 10% with NS; P = 0.5). There was no difference in time to recurrence (7.6 ± 6.9 vs 4.9 ± 4.5 months; P = 0.6). ConclusionsIn this small pilot randomized controlled trial, there was no significant difference between HNS and NS for CTI ablation; however, HNS may increase the incidence of steam pops.