Typical Atrial Flutter Research Articles

Outcomes After Supraventricular Tachycardia Ablation in Patients With Group 1 Pulmonary Hypertension.

Pulmonary hypertension (PH) is associated with right ventricular pressure overload and atrial remodeling, which may result in supraventricular tachycardias (SVTs). The outcomes of catheter SVT ablation in patients with World Health Organization (WHO) group 1 PH are incompletely characterized. We conducted a retrospective cohort study of all patients with WHO group 1 PH undergoing catheter SVT ablation during a 10-year period at a major academic tertiary care hospital. Baseline patient characteristics and procedural outcomes at 3 months and 1 year were extracted from the electronic medical record. Ablation of 60 SVTs was attempted in 38 patients with group 1 PH. The initial procedural success rates were 80% for atrial fibrillation (AF, n = 5), 89.7% for typical atrial flutter (AFL, n = 29), 57.1% for atypical AFL (n = 7), 60% for atrial tachycardia (AT, n = 15), and 75% for atrioventricular nodal reentrant tachycardia (AVNRT, n = 4). The 1-year post-procedural recurrence rates were 100% for AF (n = 4), 25% for typical AFL (n = 20), 50% for atypical AFL (n = 2), and 28.6% for AT (n = 7). No patients had recurrent AVNRT (n = 2). There were seven (18.4%) peri-procedural decompensations requiring pressor initiation and transfer to intensive care and one (2.6%) peri-procedural death. The study demonstrates that SVT ablation in group 1 PH can be performed relatively safely and effectively, albeit with lower initial success rates and higher risk of clinical decompensation than in the general population. Recurrence rates at 1 year were higher in AF and atypical AFL ablations and similar for typical AFL and AT ablations when compared to the general population.

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.

Features of Catheter Treatment of Non-Isthmus-Dependent Atrial Flutter

Atrial flutter (AF) is caused by the re-circulation of the wave of electrical excitation of the myocardium (reentry) around the anatomical substrate which circulates within the atrial tissues. This is always a macro re-entry. Such an anatomical barrier, around which circulation can occur, can be the superior or inferior vena cava, rings of the tricuspid or mitral valves, the mouth of the coronary sinus, pulmonary veins, postoperative scar.&#x0D; The aim. To determine the specifics of elimination, success rate, and long-term outcome with various preablation and postablation diagnostic techniques for non-isthmus-dependent atrial flutter (NIDAFL).&#x0D; Materials and methods. The study included 26 patients who underwent radiofrequency ablation of atypical NIDAFL.&#x0D; Results. As a result of radiofrequency ablation, a sinus rhythm was restored in 17 patients during the procedure. In 7 cases, when the typical, isthmus-dependent AF was removed, the tachycardia cycle and the morphology of the R wave changed. Mapping showed that in 7 cases the direction of the re-entry front changed, and instead of the circulation of excitation through the cavatricuspid isthmus, it then passed around the atriotomy scar. In 2 cases, a change in the cardiac cycle was observed after radiofrequency ablation, but the excitation circulation was the same around the atriotomy scar, only the tachycardia cycle increased. As a result of the use of our techniques, arrhythmia was eliminated in all 21 patients with an atriotomy AF during one procedure. Five patients with AF of a different localization of the re-entry circuit also had their arrhythmia eliminated, although 8 procedures (for five patients) were performed (on average 1.6). There were no complications. During the follow-up period of 1.8±0.7 years, 2 patients had a recurrence of arrhythmia, and they underwent a repeat procedure to eliminate the arrhythmia. One patient developed typical AF that had not been observed before, which was successfully eliminated.&#x0D; Conclusion. Catheter treatment of atypical NIDAFL is quite a non-trivial task, because, as our experience shows, several types of tachycardia occur in a significant number of patients. In cases of restoration of sinus rhythm as a result of the application, it is necessary to check the inducibility of another arrhythmia. But despite everything, catheter removal of NIDAFL is quite effective, especially for atriotomy AF, although it requires more X-ray exposure and a relatively large number of applications. The use of navigation systems has helped to improve the results of such interventions in more complex cases.

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.

Real-time cardiovascular magnetic resonance-guided radiofrequency ablation: A comprehensive review.

Cardiac magnetic resonance (CMR) imaging could enable major advantages when guiding in real-time cardiac electrophysiology procedures offering high-resolution anatomy, arrhythmia substrate, and ablation lesion visualization in the absence of ionizing radiation. Over the last decade, technologies and platforms for performing electrophysiology procedures in a CMR environment have been developed. However, performing procedures outside the conventional fluoroscopic laboratory posed technical, practical and safety concerns. The development of magnetic resonance imaging compatible ablation systems, the recording of high-quality electrograms despite significant electromagnetic interference and reliable methods for catheter visualization and lesion assessment are the main limiting factors. The first human reports, in order to establish a procedural workflow, have rationally focused on the relatively simple typical atrial flutter ablation and have shown that CMR-guided cavotricuspid isthmus ablation represents a valid alternative to conventional ablation. Potential expansion to other more complex arrhythmias, especially ventricular tachycardia and atrial fibrillation, would be of essential impact, taking into consideration the widespread use of substrate-based strategies. Importantly, all limitations need to be solved before application of CMR-guided ablation in a broad clinical setting.

Result assessment of typical atrial flutter ablation base on application of three-dimensional electroanatomy mapping at Hanoi heart hospital

Background: Atrial flutter is a rare type of arrhythmia in clinical practice, but it is a long-lasting complex arrhythmia that causes uncomfortable symptoms and serious complications. The method of ablation of atrial flutter using X-ray irradiation has many shortcomings such as prolonged irradiation time, and the success rate is only 80-85%. The method of ablation using the 3-Dimensional electrical mapping method has been widely used in typical atrial flutter ablation, but there have not been many studies evaluating its effectiveness, so we carry out this study.&#x0D; Objectives of the study: Assessment for electrocardiography, electrophysiology study characteristic, and ablation result of typical atrial flutter using three-dimensional electrical mapping.&#x0D; Research objects and methods: case series study, 17 patients diagnosed with atrial flutter were electrophysiology study and ablated from 10/2019 to 10/2022 at Hanoi Heart Hospital.&#x0D; Results: Regarding the effectiveness of atrial flutter ablation, 100% of patients with atrial flutter caused a seizure and successfully ablated atrial flutter by RF. In terms of procedure time, our study has an average of 103.53 ± 74.64 minutes for each procedure, of which the fastest is 20 minutes and the longest is 360 minutes. Regarding the time of X-ray irradiation, the average of our study was 10.67 ± 9.86 minutes, of which the shortest was 4 minutes and the longest was 45 minutes.&#x0D; Conclusion: Typical atrial flutter ablation based on 3D mapping application has had high success at Hanoi heart hospital.

Catheter navigation by intracardiac echocardiography enables zero-fluoroscopy linear lesion formation and bidirectional cavotricuspid isthmus block in patients with typical atrial flutter

IntroductionOne of the most helpful aspects of intracardiac echocardiography (ICE) implementation in electrophysiological studies (EPS) is the real-time visualisation of catheters and cardiac structures. In this prospective study, we investigated ICE-guided zero-fluoroscopy catheter navigation during radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) in patients with typical atrial flutter (AFL).Methods and resultsThirty consecutive patients (mean age 72.9 ± 11.4 years, 23 male) with ongoing (n = 23) or recent CTI-dependent AFL underwent an EPS, solely utilizing ICE for catheter navigation. Zero-fluoroscopy EPS could be successfully accomplished in all patients. Mean EPS duration was 41.4 ± 19.9 min, and mean ablation procedure duration was 20.8 ± 17.1 min. RF ablation was applied for 6.0 ± 3.1 min (50W, irrigated RF ablation). Echocardiographic parameters, such as CTI length, prominence of the Eustachian ridge (ER), and depth of the CTI pouch on the ablation plane, were assessed to analyse their correlation with EPS- or ablation procedure duration. The CTI pouch was shallower in patients with an ablation procedure duration above the median (4.8 ± 1.1 mm vs. 6.4 ± 0.9 mm, p = 0.04), suggesting a more lateral ablation plane in these patients, where the CTI musculature is stronger. CTI length or ER prominence above the respective median did not correlate with longer EPS duration.ConclusionsZero-fluoroscopy CTI ablation guided solely by intracardiac echocardiography in patients with CTI-dependent AFL is feasible and safe. ICE visualisation may help to localise the optimal ablation plane, detect and correct poor tissue contact of the catheter tip, and recognise early potential complications during the ablation procedure.Graphical

Zero fluoroscopy ablation for atrioventricular nodal reentrant tachycardia and typical atrial flutter is equally safe and effective with EnSite NavX, Carto3, and Rhythmia mapping systems.

Our purpose was to compare the procedural characteristics, success rate, and complication rate of the conventional fluoroscopic (CF) and the zero-fluoroscopic (ZF) approach in patients undergoing catheter ablation of AVNRT or typical atrial flutter (Aflu). 186 consecutive patients with an indication for AVNRT or Aflu ablation were enrolled. Based on the operator's preference, the patients were assigned to either CF or ZF group. In the ZF group EnSite NavX, Carto3, or Rhythmia EAMS were used for catheter guidance. The median age was 56 (IQR = 42-68) years, 144 patients had AVNRT, and 42 had Aflu ablation. CF approach was chosen in 123 cases, while ZF in 63 cases. ZF approach was used more often in case of AVNRT patients [56 (39%) vs. 7 (17%), p = 0.006] and in the case of female patients [43 (68%) vs. 20 (32%), p = 0.008]. Acute procedural success was obtained in all cases. There was no difference in the complication rate (1 vs. 1, p > 0.99) between the two groups. No difference was found regarding the procedure time between the CF and ZF groups [CF: 55 (46-60) min, ZF 60 (47-65) min; p = 0.487] or in the procedure time for the different EAMS [EnSite NavX: 58 (50-63) min, Carto3: 60 (44.5-66.3) min, Rhythmia: 55 (35-69) min; p = 0.887]. A similar success rate was seen at the 3-month follow-up in the two groups [41 (100%) vs. 96 (97%); p = 0.55]. The ZF approach demonstrated non-inferiority in safety and efficacy compared with CF for the AVNRT and Aflu ablations.

Utilization of 3D mapping systems in interventional electrophysiology and its impact on procedure time and fluoroscopy-Insights from the "Go for Zero Fluoroscopy" project.

The implementation of 3D mapping systems plays an important role in interventional electrophysiology (EP) in recent years. The aim of the present study was to evaluate use of 3D mapping systems regarding fluoroscopy and procedure duration. In the "Go for Zero Fluoroscopy" project 25 European centers provided data of consecutive EP procedures. Data on use of 3D mapping systems as well as utilization of contact force catheters and multipolar mapping catheters were associated with fluoroscopy time, dose area product (DAP), and procedure duration. A 3D mapping system was used in 966 (54%) cases. Use of 3D mapping for atrioventricular nodal reentry tachycardia (AVNRT) was associated with reduced fluoroscopy time (p<0.001), DAP (p=0.04) but increased procedure time (p=0.029). Moreover, fluoroscopy time (p<0.001) and DAP (p=0.005) were significantly lower in the 3D mapping group in ablation of typical atrial flutter. However, the procedure time (p<0.001) increased. Use of 3D mapping in the ablation of accessory pathway (AP) was associated with reduced fluoroscopy time (p<0.001) and DAP (p<0.001) with no significant increase in procedure time (p=0.066). In the case of atrial fibrillation, a 3D mapping system was used in 485 patients (75.8%). Additional use of a contact force catheter was associated with lower fluoroscopy time (p<0.001) and DAP (p<0.001). Use of a multipolar mapping catheter was associated with lower fluoroscopy time (p=0.002). The implementation of 3D mapping systems in the ablation of ventricular tachycardias resulted in a significant increase in the procedure time (p=0.001) without significant differences regarding the DAP (p=0.773) and fluoroscopy time (p=0.249). Use of 3D mapping systems in ablation of supraventricular tachycardias is associated with lower radiation exposure. Nevertheless, the procedure time often increases, except in the case of ablation for AP. Use of contact force catheters and multipolar mapping catheters is associated with yet lower radiation exposure values. Prospective randomized studies are needed to further elucidate potential benefit of these technological tools.

Efficacy of two-stage approach for interventional treatment of coexistent atrial fibrillation and typical atrial flutter for sinus rhythm maintenance in long-term: a prospective controlled clinical trial

Background: Atrial fibrillation (AF) and coexistent typical atrial flutter (AFL) interventional treatment strategy remains unresolved in cardiology and cardiovascular surgery. Results of this approach remain suboptimal. There are several approaches to the interventional treatment of patients with coexistent AF and AFL: simultaneous pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) radiofrequency catheter ablation (RFCA), PVI or CTI RFCA only and two-stage approach. To our knowledge, cumulative efficacy of two-stage approach has not been previously reported. The aim. This study aimed to evaluate the efficacy of two-stage approach for interventional treatment of coexistent AF and AFL for sinus rhythm maintenance in long-term. Methods: Patients (pts) (n=34) with AF and AFL aged 41–82 years (11 women) were divided into two groups (1:1): «One-stage Approach» (group 1; n=17): PVI+СTI RFСA and «Two-stage approach» (group 2; n=17): first stage — CTI RFCA (group 2.1); second stage — PVI in case of AF recurrence after RFCA (group 2.2). Primary endpoint (PEP) was defined as any recurrent atrial tachyarrhythmia at the end of follow-up; group 2 events have been considered after PVI. Secondary endpoint (SEP) — recurrent any atrial tachyarrhythmia in groups 1 and 2 after CTI RFCA in group 2. PEP and SEP were evaluated at the end of the «blind period» (3 months after procedure). Results: Registered recurrent atrial tachyarrhythmia in pts who reached PEP or SEP was AF. AFL has not been detected in any cases. PEP was noted in 8 (47.06%) pts in group 1 and 1 (5.88%) pts in group 2. Further, SEP was observed in 3 pts (17.65%) in group 1 and in 4 (23.53%) pts in group 2 (p=0.671). The probability of long-term maintenance of sinus rhythm was significantly higher in «Two-stage approach» than in «One-stage approach» (94.12% and 52.94%, respectively, p=0.001). Significant differences in procedure length and fluoroscopy time have been found. Those were longer in group 1 compared to group 2.1 (p 0.001) and in group 2.2 compared to group 2.1 (procedure duration — p 0.001; fluoroscopy time — p=0.013). No differences were noted in length of procedure and fluoroscopy time between groups 1 and 2.2 (p=0.374 and p=0.028, respectively). Conclusion: The «two-stage approach» for interventional treatment of coexistent AF and AFL results in better long-term arrhythmia-free survival than «one-stage approach» (94.12% and 52.94%, respectively, p=0.001). CTI RFCA alone in pts with coexistent AF and AFL cause 23.53% AF recurrence rate and associated with shorter procedure duration and fluoroscopy time compared to simultaneous PVI and CTI RFCA (p 0.001).

Differences between typical and reverse typical atrial flutter identified by ultrahigh resolution mapping.

Although atrial flutter (AFL) is a common arrhythmia that is based on a macro-reentrant tachycardia around the tricuspid annulus, the factors giving rise to typical AFL (t-AFL) versus reverse typical AFL (rt-AFL) are unknown. To investigate the difference between t-AFL and rt-AFL circuits using ultrahigh resolution mapping of the right atrium. We investigated 30 isthmus-dependent AFL patients (mean age 71, 28 male) who underwent first-time cavo-tricuspid isthmus (CTI) ablation guided by Boston Scientific's Rhythmia mapping system and divided them into two groups: t-AFL (22 patients) and rt-AFL (8 patients). We compared the anatomy and electrophysiology of their reentrant circuits. Baseline patient characteristics, use of antiarrhythmic drugs, prevalence of atrial fibrillation, AFL cycle length (227.1 ± 21.4 vs. 245.5 ± 36.0 ms, p = .10), and CTI length (31.9 ± 8.3 vs. 31.1 ± 5.2 mm, p = .80) did not differ between the two groups. Functional block was observed at the crista terminalis in 16 patients and at the sinus venosus in 11. No functional block was observed in three patients, all of whom belonged to the rt-AFL group. That is, functional block was observed in 100% of the t-AFL group as opposed to 5/8 (62.5%) of the rt-AFL (p < .05). Slow conduction zones were frequently observed at the intra-atrial septum in the t-AFL group and at the CTI in the rt-AFL group. Mapping with ultrahigh-resolution mapping showed differences between t-AFL and rt-AFL in conduction properties in the right atrium and around the tricuspid valve, which suggested directional mechanisms.

Outcome of the elective or online radiofrequency ablation of typical atrial flutter.

Radiofrequency ablation of the cavotricuspid isthmus is currently the first-choice treatment of typical atrial flutter and usually it is performed electively. The purpose of this study was to see whether performing on-line ablation has similar clinical results compared to the conventional strategy. Consecutive patients (465) who underwent ablation of the cavotricuspid isthmus for typical atrial flutter (AFL) at our electrophysiology laboratory in the 2008-2017 decade were studied. We evaluated the acute and long-term clinical outcomes of those who were treated electively (337) compared to those who had online ablation (128), that is within 24 hours of presenting to the Department of Cardiology. In patients treated on an emergency basis, a transesophageal echocardiogram was performed to rule atrial thrombi when needed. No significant intraprocedural difference was observed between the 2 patient groups, with comparable acute electrophysiological success (99% vs. 98%) and serious complications. Even at the subsequent 4-year follow-up, there were no significant differences in the recurrence of typical AFL, onset of atrial fibrillation and other clinical events. Online ablation of typical atrial flutter performed at the time of the clinical presentation of the arrhythmia, was shown to be comparable in terms of procedural safety and clinical efficacy in the short and long term compared to an elective ablation strategy.

Complex Wavefront Interaction With the Sinoatrial Node Affects Circuit Stability in Typical Atrial Flutter: A Detailed 3D Computer Modelling Study

Complex Wavefront Interaction With the Sinoatrial Node Affects Circuit Stability in Typical Atrial Flutter: A Detailed 3D Computer Modelling Study

Comparative analysis of long-term outcomes of thoracoscopic and ablation index-guided catheter ablation in patients with non-paroxysmal atrial fibrillation

Aim. To conduct a comparative assessment of the long-term results of thoracoscopic and catheter ablation using the ablation index in patients with non-paroxysmal atrial fibrillation (AF).Methods. A comparative analysis of the long-term results of catheter ablation using the ablation index - group № 1 (36 patients) and thoracoscopic ablation with the left atrial appendage exclusion - group № 2 (42 patients) was performed.Results. The effectiveness of catheter ablation was 57.14%, thoracoscopic ablation - 67.5% at 12-month followup (р=0,128). There were also no statistically significant differences in safety (p=0.55). Analyzing the structure of postprocedural atrial tachycardias in group №1 was demonstrated that AF recurrence was in 93.3%, in group №2 - in 50%. Atypical atrial flutter was documented in 6.6% of cases in group №1 and in 31.5% - in group №2. Typical atrial flutter was documented only in group №2 (18.75% (3)). However, AF recurrence was more common in the catheter ablation group after 6 months of follow-up (p=0.04).Conclusion. Catheter and thoracoscopic ablation are comparable in terms of overall efficacy and safety, however, thoracoscopic ablation provides greater freedom from AF in a 6 month.

Tissue characterisation of acute ablation lesions in the right atrium during CMR-guided atrial flutter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac magnetic resonance (CMR)-guided ablation therapy offers a unique opportunity and incentive to investigate acute ablation lesions. Until present, human studies only used T2-weighted imaging (T2WI) and late gadolinium enhancement (LGE) to assess acute ablation lesions. Purpose To investigate the tissue characteristics of acute ablation lesions during CMR-guided atrial flutter ablation, by combining T2WI and LGE with first-pass perfusion and T1 mapping. Methods Thirteen patients with typical isthmus-dependent atrial flutter were prospectively enrolled and treated with CMR-guided ablation. Pre-ablation tissue characterisation consisted of T2WI and T1 mapping. Postablation imaging was performed directly after application of the primary ablation lesions and included T2WI (n=12), first-pass perfusion (n=9), LGE (n=9) and T1 mapping (n=7). For analysis of T2WI an edema ratio (ER; i.e. the signal intensity ratio between myocardium and reference skeletal muscle) &amp;gt; 2.0 was considered indicative of edema. Post-processing comprised native T1 measurements in three regions of the ablation line (near the tricuspid annulus, mid region, near the caval vein) on pre- and post-ablation images by two independent observers. For each region, the change in T1 value was expressed as the absolute increase (in ms) and the relative increase (in %). A third observer, blinded to the CMR results, reviewed which region(s) had required additional RF lesions after post-ablation CMR imaging. Results In 12 out of 13 patients CMR-guided atrial flutter ablation was successful, resulting in bidirectional conduction block. In 1 patient the ablation procedure was completed in the conventional electrophysiology lab, hampering acute post-ablation imaging. In all patients T2WI demonstrated edema in the ablation region. The ER increased from 1.6 ± 0.3 to 3.3 ± 0.5 post-ablation (p&amp;lt;0.001). Perfusion defects were present in 9/9 patients. The LGE images demonstrated hyperenhancement with a central area of hypo-enhancement in 9/9 patients, suggestive of ablation necrosis and previously reported areas of microvascular damage and hemorrhage. Right atrial T1 mapping was feasible in 20/21 regions (in 1 case artifacts from the adjacent catheter hampered analysis) and reproducible (r 0.981, ICC 0.939). The post-ablation increase in T1 value was significantly different between regions that did (n=10) and did not (n=10) require additional RF lesions, T1 increase was 46 ± 90ms versus 133 ± 69ms (p = 0.026), and 4.7 ± 9.1% versus 13.2 ± 6.8% (p = 0.028) respectively. Conclusion CMR tissue characterisation of acute ablation lesions during CMR-guided atrial flutter ablation demonstrates edema, perfusion defects, and necrosis with a core of microvascular damage. Atrial T1 mapping of the acute ablation lesion is feasible and reproducible, and might distinguish regions that require additional RF applications.

The effect of first step right atrial mapping (FRAM) on ablation duration and fluoroscopy exposure during cavotricuspid isthmus ablation of atrial flutter.

To investigate the clinical significance of right atrial mapping prior to cavotricuspid isthmus (CTI) ablation in patients with typical atrial flutter (AFL). Clinical and ablation parameters were retrospectively assessed and compared in patients undergoing CTI ablation with or without a first-step right atrial mapping (FRAM) by using the CARTO 3D mapping system. CTI block by radiofrequency ablation (RFA) was achieved in all 143 patients. In the FRAM group there was a shorter ablation duration and fluoroscopy exposure compared with the non-FRAM group. CHA2DS2-VASc score was associated with higher ablation durations, more ablation applications and increased fluoroscopy exposure. Body mass index (BMI) was associated with longer ablation duration and more ablation applications. Furthermore, patients with reduced left ventricular ejection fraction (LVEF) had longer ablation durations and more fluoroscopy exposure. One patient in the non-FRAM group developed cardiac effusion after ablation. None of the patients had recurrence after 6 months of follow-up. Patients with high BMI, high CHA2DS2-VASc score and reduced LVEF may benefit from the FRAM approach by reducing ablation duration, number of ablation applications and fluoroscopy exposure.

Obstructive Sleep Apnea as a Predictor of Inducible Atrial Flutter During Pulmonary Vein Isolation in Patients With Atrial Fibrillation: Clinical Significance and Follow-Up Outcomes.

Atrial fibrillation (AF) and atrial flutter (AFL) often coexist in patients and may lead to severe symptoms and complications. Despite their coexistence, prophylactic cavotricuspid isthmus (CTI) ablation has failed to reduce the incidence of recurrent AF or new onset AFL. In contrast, the presence of inducible AFL during pulmonary vein isolation (PVI) has been shown to be predictive of symptomatic AFL during follow-up. However, the potential role of obstructive sleep apnea (OSA) as a predictor of inducible AFL during PVI in patients with AF remains unclear. Therefore, this study aimed to examine the potential role of OSA as a predictor of inducible AFL during PVI in patients with AF and reexamine the clinical significance of inducible AFL during PVI in terms of recurrent AFL or AF during follow-up. We conducted a single-center, non-randomized retrospective study on patients who underwent PVI between October 2013 and December 2020. A total of 192 patients were included in the study after screening 257 patients for exclusion criteria, which included a previous history of AFL or previous PVI or Maze procedure. All patients underwent a transesophageal echocardiogram (TEE) prior to their ablation to rule out a left atrial appendage thrombus. The PVI was performed using both fluoroscopic and electroanatomic mapping derived from intracardiac echocardiography. After the confirmation of PVI, additional electrophysiology (EP) testing was performed. AFL was classified as typical or atypical based on the origin and activation pattern. Descriptive and frequency statistics were performed to describe the demographic and clinical characteristics of the sample, and Chi-square and Fisher's exact tests were used to compare independent groups on categorical outcomes. Logistic regression analysis was performed to adjust for confounding variables. The study was approved by the Institutional Review Board, and informed consent was waived given the retrospective nature of the study. Of the 192 patients included in the study, 52% (n = 100) had inducible AFL after PVI, with 43% (n = 82) having typical right AFL. Bivariate analysis showed statistically significant differences between the groups for OSA (P = 0.04) and persistent AF (P = 0.047) when examining the outcome of any inducible AFL. Similarly, only OSA (P = 0.04) and persistent AF (P = 0.043) were significant when examining the outcome of typical right AFL. Multivariate analysis showed that only OSA was significantly associated with any inducible AFL after controlling for other variables (adjusted odds ratio (AOR) = 1.92, 95% confidence interval (CI): 1.003 - 3.69, P = 0.049). Of the 100 patients with inducible AFL, 89 underwent additional ablation for AFL prior to completion of their procedure. At 1 year, the rates of recurrence for AF, AFL, and either AF or AFL were 31%, 10%, and 38%, respectively. There was no significant difference in the rates of recurrence of AF, AFL, or either AF/AFL at 1 year when accounting for the presence of inducible AFL or the efficacy of additional AFL ablation. In conclusion, our study found a high incidence of inducible AFL during PVI, particularly among patients with OSA. However, the clinical significance of inducible AFL in relation to the recurrence rates of AF or AFL at 1-year post-PVI remains unclear. Our findings suggest that successful ablation of inducible AFL during PVI may not provide clinical benefit in reducing AF or AFL recurrence. To establish the clinical significance of inducible AFL during PVI in various patient populations, further prospective studies with larger sample sizes and longer follow-up periods are necessary.

Diagnosing Atypical Flutter in the Post-atrial Fibrillation Ablation Patient: A Case Report.

Late atrial arrhythmias after catheter ablation for atrial fibrillation occur in up to 30% of post-ablation patients and are increasingly encountered by emergency physicians. However, diagnosing the exact mechanism of the arrhythmia on the surface electrocardiogram (ECG) remains challenging due to atrial scarring leading to heterogeneous P-wave morphology. A 74-year-old male with a history of prior catheter ablation for atrial fibrillation presented with palpitations and subacute symptoms of heart failure. The patient's ECG revealed narrow complex tachycardia with more P waves than QRS complexes. The differential diagnosis included typical flutter, atypical flutter, and focal atrial tachycardias with 2:1 conduction block. P waves were positive in V1 and across all precordial leads (absent precordial transition). This favors atypical flutter originating from the left atrium over typical cavotricuspid isthmus-dependent right atrial flutter. Transthoracic echocardiogram showed a reduced ejection fraction due to tachycardia-mediated cardiomyopathy. The patient underwent a repeat electrophysiology study and ablation, which confirmed the presence of an atypical flutter circuit using the mitral annulus, known as perimitral flutter. Repeat catheter ablation resulted in maintenance of sinus rhythm. At follow-up, his ejection fraction recovered. Recognizing ECG findings suggestive of atypical flutter impacts initial emergency department decisions and triage as atypical flutter post-atrial fibrillation ablation is frequently resistant to rate-controlling medications and often requires cardiology and/or electrophysiology consultation if available.

Zero or minimal fluoroscopy catheter ablation: feasibility, efficacy, and safety results

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Fluoroscopy has been used to guide catheter ablation since the beginning of this technique, despite its important secondary effects on both patients and operators. However, three-dimensional electroanatomic mapping systems (3D-EAMP) enable ablation of some substrates using zero or minimal fluoroscopy. The aim of this study is to explore the feasibility, efficacy and safety of a zero or minimal fluoroscopy approach in our center. Methods We performed a retrospective observational study with consecutive patients that underwent catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT), accessory pathways (AP), focal atrial tachycardia and typical atrial flutter in our center, between January 2020 and November 2022. Vascular access was obtained by ultrasound guidance. The objective was zero-fluoroscopy for all patients except those with left AP, in which minimal fluoroscopy was allowed for the transseptal access (ablations with retrograde aortic approach were excluded). Results 319 consecutive patients were included. 56% were male, mean age was 55 ± 16 years. The following substrates were included: AVNRT (43%), typical atrial flutter (41%), AP (12%) and focal atrial tachycardia (5%). We achieved zero-fluoroscopy use in 99.3% of right substrates, using fluoroscopy in just two cases to introduce catheters through femoral access. Mean fluoroscopy time in left AP was 6.1 minutes. Ablation was successful in 97% of cases, and we just experienced three complications (moderate pericardial effusion, femoral hematoma and femoral arteriovenous fistula, all of them solved without requiring intervention). After a mean follow- up of 17 ± 14 months, we noticed three recurrences, performing in all of them a successful second ablation procedure. Baseline characteristics and procedure details are shown in table 1. Conclusions Catheter ablation of simple substrates with zero or minimal fluoroscopy using 3D mapping systems is feasible, effective and safe, with high success rate and low complications rate.

Safety and efficacy of pulmonary vein isolation using pulsed field ablation with or without 3D mapping system for paroxysmal atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulsed field ablation (PFA) has recently been introduced as a novel routine ablation technology for paroxysmal atrial fibrillation (PAF). PFA can be performed "cryo-style" using fluoroscopy only, or additional pre- and post-ablation high-density 3D bipolar voltage maps can be performed to assess lesion formation and acute pulmonary vein isolation. We compared 6-month outcome after PFA using fluoroscopy only (X-ray) vs. PFA guided by 3D mapping (3D). Methods In PAF patients, PVI in conscious sedation using a steerable sheath and a pentaspline over-the-wire basket and flower PFA catheter was performed. In a subset of patients, pre- and post-ablation high-density bipolar voltage 3D maps (Carto 3D) were performed. Procedural parameters, acute success, in-hospital safety and arrhythmia recurrence were assessed over 6-month follow-up. Efficacy was evaluated by freedom from a ≥ 30-sec. recurrence of AF/atrial flutter (AFL)/atrial tachycardia (AT). Follow-up included 7-day Holter ECGs and/or telephonic interviews at days 90 and 180 after ablation. Results This study included a total of 101 patients (mean age: 65±10 years; 42% female) in whom 6-month follow-up data were available. There were no selection criteria for the use of 3D mapping. Pre- and post-ablation high-density maps were performed in 34/101 (34%) of patients. Mean CHA2DS2-VASc-score was 2,1±1,6. Median duration since first AF diagnosis was 21 [3-60] months. Skin-to skin procedure time was 56±20 in the X-ray group vs. 118±22 min in the 3D group, respectively (p&amp;lt;0,0001). Fluoroscopy time was 17±7 in the X-ray group vs. 21±6 in the 3D group, respectively (p&amp;lt;0,01). Acute pulmonary vein isolation rate was 100% in both groups. Primary adverse events occurred in 0% of patients in the X-ray group vs. 2/34 (6%) in the 3D group (2 pericardial tamponades), respectively (p=ns). During a mean follow-up of 204±82 days, 54/67 (81%) in the X-ray group vs. 27/34 (79%) in the 3D group remained free of any symptomatic or documented AF/AFL/AT episode after a single procedure (p=ns). In 4/13 (31%) patients in the X-ray group, a re-do procedure was performed, 2 patients had durable PVI with typical or atypical atrial flutter, 1 patient had reconnection of both posterior carinae and 1 patient had typical atrial flutter degenerating in AF. In 3/7 (43%) patients in the 3D group, a re-do procedure was performed, 2 patients had durable PVI with typical or atypical atrial flutter and 1 patient had reconnection of the LIPV. Conclusions PVI using PFA with or without 3D mapping system resulted in a similar 6-month atrial arrhythmia recurrence rate and safety profile. Procedure and fluoroscopy times were significantly shorter in the fluoroscopy only group.