Lasso Catheter Research Articles

Validation Strategy for Pulmonary Vein Isolation in Patients With Paroxysmal Atrial Fibrillation in Long-Term Maintaining Sinus Rhythm: A Randomized Controlled Study.

Background: Data comparing the outcomes of loose versus rigorous validation strategies for pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF) are limited. We aimed to prospectively assess the effectiveness of loose versus rigorous validation for PVI in patients with PAF with a maintained sinus rhythm. Methods: Patients (n = 117) with PAF were randomized to receive either loose validation (n = 59) or rigorous validation (n = 58) after PVI. The presence of dormant conduction in loose validation was assessed only by adenosine administration followed by isoproterenol infusion. The complete absence of pulmonary vein (PV) potentials in rigorous validation was confirmed by the combination of the Lasso catheter with isoproterenol plus adenosine. Dormant conduction, revealed by validation after PVI, was ablated until all reconnections were eliminated. Results: The procedure time in the rigorous validation group was greater than that in the loose validation group (161.3 ± 52.7 min vs. 142.5 ± 37.6 min, p=0.03, respectively). After successful PVI, the detection of dormant PV reconnections in the rigorous validation group was significantly greater than that in the loose validation group (69.0% vs. 37.3%, p=0.001). However, after reisolation of the sites of dormant PV conduction, the postablation recurrence rates in 1.3 years were similar between the groups (79.2% vs. 83.6%, p=0.67). Conclusion: Rigorous validation can reveal dormant conduction in more than two-thirds of patients with PAF undergoing PVI. However, rigorous validation and additional ablation of the resulting connections do not improve long-term outcomes when a protocol that includes electrophysiological confirmation and pharmacological validation is used.

A Case of Presumptive Marshall Bundle Conduction Between the Left Atrium and Left Superior Pulmonary Vein During Box Isolation

A 65-year-old man with symptomatic persistent atrial fibrillation was referred for initial radiofrequency catheter ablation. He underwent box isolation to simultaneously isolate all four pulmonary veins (PVs) and the posterior wall of the left atrium (LA). During the box isolation with a double lasso catheter positioned in both the left superior and right superior PVs, the atrial fibrillation terminated spontaneously. After the box lesion set was created, conduction was still observed between the LA and PVs. After an additional radiofrequency energy delivery to the bottom line of the box lesion, the activation sequence of the PVs became uniform during sinus rhythm and pacing from the coronary sinus (CS), indicating that only one more conduction pathway was present. The 3-dimensional map revealed that the earliest activation site within the box lesion was located in the anterior aspect of the left superior PV during pacing from the CS, whereas that of the LA during pacing from the superior right PV within the box was on the posterolateral LA wall below the left inferior When a 2 Fr electrode catheter was inserted into the vein of Marshall (VOM) and paced within the BOX, VOM potentials preceded CS potentials. When the left superior PV anterior wall, the earliest site of excitation within the box, was energized, simultaneous posterior pulmonary vein wall isolation was completed. We experienced a case in which Marshall bundle conduction between the left atrium and the pulmonary vein was assumed.

Association between different catheter designs for the characterization of the left atrial substrate

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): The study was supported by an investigator sponsored grant (Boston Scientific). Background Bipolar voltage electrograms (BVE) for left atrial (LA) substrate characterization strongly depend on the catheter design and electrode configuration. Purpose The aim of the study was to compare bipolar voltage electrograms (BVE) obtained from the left atrium using four different established mapping catheters and to deduce the individual catheter-specific cut-offs for scar and healthy myocardial tissue. Methods We prospectively included 25 consecutive patients referred for catheter ablation for atrial fibrillation recurrence after index PVI. The pipeline of the analysis leading to the individual cut-off for every catheter based on a reference catheter value is shown in the figure. In detail, consecutive high-resolution electroanatomic mapping was performed using a multipolar catheter (Orion), a duo-decapolar variable circular mapping catheter (Lasso), an irrigated ablation catheter with micro electrodes (MIFI) and a 4.5 mm tip-size irrigated ablation catheter (Nav). BVEs for the four catheters were compared in voxels with a size of 3x3x3mm^3 (Figure, top left). Total least squares regression was performed for every patient to investigate the logarithmic relationship between the BVE measured by two different catheter types (Figure, top right). The mean equivalent BVE cut-off over all patients for every catheter was calculated for the reference cut-offs of 0.1 mV, 0.2 mV, 0.5 mV, 1.0 mV, and 1.5 mV (Figure, bottom left). Results Correlation between the four different BVE maps for the 25 patients showed a slight individual variation between the patients. Compared to the BVE cut-offs from the standard Nav catheter with a 4.5 mm tip, the scar cut-off using the Orion catheter must be lowered to 0.034 mV for a 0.1 mV cut-off, to 0.09 mV for a 0.2 mV cut-off, and to 0.35 mV for the 0.5 mV cut-off (Figure). Similar values hold true for a Lasso map as comparator (Figure). For healthy tissue above 1 mV, similar cut-offs to the reference values might be advisable. Conclusion In contrast to the established Nav or Lasso catheter, the scar voltage cut-off for the Orion catheter needs to be lowered to 0.1 mV instead of the 0.2 mV cut-off and approx. 0.35 mV for a 0.5 mV cut-off. At lower voltages the difference between the catheters increases. The presented connective table enables to transfer the studies of left atrial substrate characterizations using different catheter types.

PO-02-122 TRACKING AND ABLATING THE MUSCLE SLEEVE/FASCICLE FOR PULMONARY VEIN ISOLATION

Pulmonary vein isolation (PVI) remains the cornerstone for atrial fibrillation (AF) ablation. However, it yields unsatisfactory outcomes requiring repeat procedures especially in persistent AF. Additional linear ablation, or of complex fractionated atrial electrograms, atrial rotors or ganglionated plexi prolongs procedure time and increases complications with small additional benefits. We evaluated the efficacy of a new method of tracking and ablating pulmonary vein (PV) muscle sleeve/fascicle followed by wide area circumferential ablation (WACA) as a method of treatment of AF. To track a muscle sleeve/fascicle, a Lasso catheter was placed into one PV and based on the electrograms pattern on the catheter, sites of exit of muscle sleeves/fascicles were determined along the wide area circumferential ablation (WACA) line. (Panel A of figure shows the electrogram pattern, which suggests two muscle fascicles [red and blue arrows]). Focal ablation at sites on the planned WACA line was then performed to interrupt the muscle sleeve/fascicle connection with atrium (Panel B and C of figure shows point ablation resulting in partial and complete isolation; black arrow marks the location of ablation catheter). The same method was repeated to the ipsilateral PV before full WACA of both PVs was commenced. The strategy was repeated on the contralateral PVs. Ablation of these fascicle-atrium connections resulted in PVI isolation before WACA was completed in all 18 patients. Intravenous adenosine was used at the end to elicit dormant PV connections. We schematically labeled the areas around the PVs into zones and summarized the location of these muscle fascicles in each patient. (Panel D; each dot represents a fascicle and color matches with the PV with which it is associated). Eighteen patients (61±11 years old, 56% male) with AF (12 persistent {67%}) were analyzed in this study. Fascicles were identified in all patients and focal ablation of fascicles resulted in isolation of the PVs. In addition to PVI, 8 had Cavotricuspid isthmus ablation, 1 for right focal atrial tachycardia (AT), one left focal AT, and 1 for biatrial reentrant AT. With a follow-up of 155 ±120 days, 83% of paroxysmal and 75% of persistent AF remained in sinus rhythm. Left atrial dwell time for PVI alone was less than 2 hrs and no complications were seen. The tracking and ablating muscle sleeve/fascicle before performing WACA is a strategy with outcomes superior to previously reported in literature.

46 ELECTRO-CATHETER EXTRACTION IN JUGULAR ACCESS:METHODS AND TECHNIQUES

Abstract A significant increase of Pacemaker implantation has resulted in an increase in the number of extractions due to the onset of infections and malfunctions. The transvenous leads extraction by means of a dilator sheath can be difficult for possible fibrotic or calcified adhesions and vegetations along the path of the leads. In 90% of cases the firm adhesions are in the superior vena cava-right atrium, of the tricuspid valve ring of the papillary muscles of the right ventricle and in the lead insertion zone. If standard extraction from the implantation site is difficult along the axis subclavian venous-anonymous vena-superior vena cava, due to the presence of tenacious adhesions along the course of the leads, it is necessary to resort to a right internal jugular approach. During the standard extraction there are particularly delicate points like the anonymous trunk and superior vena cava. At this point the sheath is perpendicular to the vein and there is the possibility of vascular injury. Moreover, the twisting of the sheath doesn't permit a favorable approach at the second part of the lead. In fact, it is very difficult that the force applied during the rotation of the sheaths arrives at the tip of the sheath and is not sufficient to win against the adherences. In this case a right internal jugular approach becomes necessary. This method facilitates the lead extraction because the position of the jugular vein is rectilinear with the superior vein cava and the right part of the heart which permits a better and more precise alignment of the sheath with the vein and hearth cavity. The sheath-lead system has a parallel progress at anonymous vein, the superior vein cava and right atrium. This method reduces vascular injury and makes sheath rotation movement more efficient for resection of adherence, furthermore, for large vegetations it is possible to use big sheaths to simplify the resection. The jugular approach involves the introduction from the femoral vein of a pig tale or a deflectable catheter to take the lead into the right atrium making it intravascular. Furthermore, we proceed with the canalization of the jugular vein in sterile method. Then position an introductory 11 Fr by which a lasso catheter will be introduced. The objective is to capture the lead and bring it out of the jugular vein. Then, the operator will apply the sheath-catheter system and given the good position will proceed with the extraction of the lead, by using rotating movements. The entire procedure is done with a fluoroscopy guide with the use of septums to define the field of view only of area of interest and the exposure of the operators. During the important steps such as the capture of the lead by lasso, the use of ad hoc projections, that help the operator in capturing images, is essential to have a clear reference of the position within the atrium of the catheter itself. During the entire procedure, the modulation of the radiant dose is very important, in fact a Low Dose approach can be chosen at first while doses are increased when needed. Radiation protection in these procedures, which can be challenging from a fluoroscopic point of view, is essential. The success of the procedure is the result of skills and experience of all operators engaged: doctors, nurses, and radiology technicians. Figure 1 Use of pigtail to capture the catheter (left); catheter lasso (center); sheath extraction (right)

Impact of comorbidities and ablation strategy on outcome after pulmonary vein isolation with cryo-balloon in patients with non- paroxysmal atrial fibrillation

Abstract Background Presence of several comorbidities in patients with atrial fibrillation is well known, but impact of them on outcome after pulmonary vein isolation with cryo-balloon is not enough investigated. First aim of the study was analysis of the impact of comorbidities on long term outcome after PVI with cryo-balloon new generation (CBA) and secondary goal was evaluation of the impact of additional posterior roof ablation (PRA) in these patients. Methods Patients with non-paroxysmal AF ablated with CBA in our institution since May 2012 and completed follow up >3 months were enrolled in the study. The history of AF, cardiac comorbidities (CAD, Non ischemic-cardiomyopathy, heart insufficiency, right ventricular dysfunction) diabetes mellitus, and renal failure were assessed at admission, all patients received echocardiographic examination and blood test. After a single trans-septal access and PV angiography PVI was performed using a 28-mm CBA. Mapping of PV signals before, during, and after each cryo application was performed with a 3F lasso catheter. The procedural endpoint after PVI was defined as complete elimination of all fragmented signals at the PV antrum with verification of entrance and exit block. In some patients PRA was performed additionally to PVI at discretion of physician. The primary endpoint of this study was the first documented recurrence of atrial tachyarrhythmia (>30 sec.), hospitalization due to cardio-vascular cause, re-do procedure or re-administration of anti-arrhythmic drugs. Results Among 560 patients 78 (13.9%) had no comorbidity and 299 (53.4%) were lasted with >1 comorbidity. A total of 260 (46.4%) recurrences were obtained within median follow up of 28 (12–57) months. Female gender, long time from first diagnosis >12 months and cardiac comorbidity were revealed to be independent predictors for long term recurrences whereas additional PRA performed in 176 pts independently improved outcome (61.9% vs 49.7%). Conclusion Cardiac comorbidities increased probability of post ablation recurrences, but performing of additional posterior roof ablation improved outcome in our cohort. These results should be confirmed in multi-center randomized study Funding Acknowledgement Type of funding sources: None.

The Influence of Lead-Related Venous Obstruction on the Complexity and Outcomes of Transvenous Lead Extraction.

Background: Little is known about lead-related venous stenosis/occlusion (LRVSO), and the influence of LRVSO on the complexity and outcomes of transvenous lead extraction (TLE) is debated in the literature. Methods: We performed a retrospective analysis of venograms from 2909 patients who underwent TLE between 2008 and 2021 at a high-volume center. Results: Advanced LRVSO was more common in elderly men with a high Charlson comorbidity index. Procedure duration, extraction of superfluous leads, occurrence of any technical difficulty, lead-to-lead binding, fracture of the lead being extracted, need to use alternative approach and lasso catheters or metal sheaths were found to be associated with LRVSO. The presence of LRVSO had no impact on the number of major complications including TLE-related tricuspid valve damage. The achievement of complete procedural or clinical success did not depend on the presence of LRVSO. Long-term mortality, in contrast to periprocedural and short-term mortality, was significantly worse in the groups with LRSVO. Conclusions: LRVSO can be considered as an additional TLE-related risk factor. The effect of LRVSO on major complications including periprocedural mortality and on short-term mortality has not been established. However, LRVSO has been associated with poor long-term survival.

Rationale and Study Design for Evaluating the Efficacy and Safety of Intracardiac Echocardiography-Guided Minimal-Fluoroscopy Ablation in Patients with Paroxysmal Atrial Fibrillation: A Non-Inferior, Multi-Center, Prospective Randomized Controlled Trial (PAF-ICE Trial)

Abstract The feasibility and safety of intracardiac echocardiography (ICE)-guided catheter ablation for atrial fibrillation (AF) using a minimal/zero-fluoroscopy approach have recently been reported. This approach helps to reduce ionizing radiation exposure and orthopedic complications resulting from using lead aprons. The objectives of this planned prospective, multicenter randomized controlled trial (RCT) (paroxysmal AF (PAF)-ICE trial; ChiCTR2000033624) are to evaluate the efficacy and safety of ICE-guided minimal-fluoroscopy ablation in patients with PAF and the impact on occupational hazards among lab staff. Patients will be randomized in a 1:1 ratio to 2 groups: minimal fluoroscopy group (n = 216) and traditional approach group (n = 216). In the minimal fluoroscopy group, an ICE catheter will be used for geometry/anatomic construction, transseptal puncture, catheter tracking, and effusion monitoring. Pulmonary vein isolation (PVI) will be performed using an open-irrigated radiofrequency SmartTouch Surround Flow or SmartTouch catheter (Biosense Webster, Diamond Bar, California, USA), and confirmed by a multipolar Lasso or PentaRay catheter (Biosense Webster). In the traditional approach group, an ICE catheter will not be used. Transseptal puncture will be performed under fluoroscopic guidance, with all geometries constructed by mapping the catheters. The primary efficacy endpoint is freedom from AF recurrence (without antiarrhythmic medications) at 12 months after ablation. Other endpoints include duration of lead apron use, measures of intra-procedural efficiency, and peri-procedural complications. This RCT will evaluate the efficacy and safety of ICE-guided minimal-fluoroscopy ablation in patients with PAF, also evaluate the benefits to lab staff (regarding reducing occupational hazards) related to this “minimal/zero-fluoroscopy” and “leadless” mode.

Transseptal puncture through the atrial septal occluder in patient with atrial fibrillation for guided radiofrequency ablation procedure using remote magnetic navigation: A clinical case

Access to the left atrium during transseptal puncture for radiofrequency ablation in patients with atrial fibrillation (AF) and implanted atrial septal occluder can be challenging. This is particularly true when the occluder covers the entire septum and there is no ideal puncture site. This might lead to potential difficulties in arrhythmia treatment.A 59-year-old patient with drug refractory AF, a dilated left atrium, and an implanted atrial septal occluder underwent double transseptal puncture through atrial septal occluder with subsequent pulmonary vein isolation using remote magnetic navigation. The effectiveness of the manipulation was confirmed by intraoperative stimulation from the Lasso catheter and by Holter monitoring data post-operation. It was revealed that the patient had sinus rhythm and no complications occurred. There were no shunts at the occluder level on transthoracic echocardiography, and there were no atrial tachyarrhythmias during the nine-month follow up period without antiarrhythmic drugs. The presented clinical case demonstrates the safety and efficacy of transseptal puncture through an implanted occluder in the interatrial septum to perform re-ablation using robotic magnetic navigation in a patient with AF.Received 21 October 2020. Revised 20 November 2020. Accepted 25 November 2020.Funding: The work is supported by a grant of the President of the Russian Federation No. МД-1997.2020.7.Conflict of interest: Authors declare no conflict of interest.Author contributions Drafting the article: А.V. Ponomarenko, R.E. Zhizhov, V.V. Baranova, E.V. Fisher, A.B. RomanovLiterature review: А.V. Ponomarenko, R.E. Zhizhov, V.V. Baranova, E.V. FisherIllustrations: А.V. Ponomarenko, A.B. RomanovCritical revision of the article: А.V. Ponomarenko, R.E. Zhizhov, V.V. Baranova, A.M. Chernyavskiy, A.B. RomanovSurgical treatment: N.А. Yelemessov, I.S. Peregudov, V.V. Shabanov, A.B. RomanovFinal approval of the version to be published: А.V. Ponomarenko, N.А. Yelemessov, I.S. Peregudov, R.E. Zhizhov, V.V. Baranova, E.V. Fisher, V.V. Shabanov, A.M. Chernyavskiy, A.B. Romanov

Comparison of Unipolar and Bipolar Voltage Mapping for Localization of Left Atrial Arrhythmogenic Substrate in Patients With Atrial Fibrillation.

Background: Presence of left atrial low voltage substrate in bipolar voltage mapping is associated with increased arrhythmia recurrences following pulmonary vein isolation for atrial fibrillation (AF). Besides local myocardial fibrosis, bipolar voltage amplitudes may be influenced by inter-electrode spacing and bipole-to-wavefront-angle. It is unclear to what extent these impact low voltage areas (LVA) in the clinical setting. Alternatively, unipolar electrogram voltage is not affected by these factors but requires advanced filtering.Objectives: To assess the relationship between bipolar and unipolar voltage mapping in sinus rhythm (SR) and AF and identify if the electrogram recording mode affects the quantification and localization of LVA.Methods: Patients (n = 28, 66±7 years, 46% male, 82% persistent AF, 32% redo-procedures) underwent high-density (>1,200 sites, 20 ± 10 sites/cm2, using a 20-pole 2-6-2 mm-spaced Lasso) voltage mapping in SR and AF. Bipolar LVA were defined using four different thresholds described in literature: <0.5 and <1 mV in SR, <0.35 and <0.5 mV in AF. The optimal unipolar voltage threshold resulting in the highest agreement in both unipolar and bipolar mapping modes was determined. The impact of the inter-electrode distance (2 vs. 6 mm) on the correlation was assessed. Regional analysis was performed using an 11-segment left atrial model.Results: Patients had relevant bipolar LVA (23 ± 23 cm2 at <0.5 mV in SR and 42 ± 26 cm2 at <0.5 mV in AF). 90 ± 5% (in SR) and 85 ± 5% (AF) of mapped sites were concordantly classified as high or low voltage in both mapping modes. Discordant mapping sites located to the border zone of LVA. Bipolar voltage mapping using 2 vs. 6 mm inter-electrode distances increased the portion of matched mapping points by 4%. The unipolar thresholds (y) which resulted in a high spatial concordance can be calculated from the bipolar threshold (x) using following linear equations: y = 1.06x + 0.26mV (r = 0.994) for SR and y = 1.22x + 0.12mV (r = 0.998) for AF.Conclusion: Bipolar and unipolar voltage maps are highly correlated, in SR and AF. While bipole orientation and inter-electrode spacing are theoretical confounders, their impact is unlikely to be of clinical importance for localization of LVA, when mapping is performed at high density with a 20-polar Lasso catheter.

P1006Cryo-balloon ablation in elderly; Outcome and prediction of recurrence

Abstract Background It is well known that prevalence of atrial fibrillation correlates with age, however the data on ablation of atrial fibrillation in elderly patients is poor. Aim of this study was analysis of outcome and prediction of recurrence after cryo-balloon ablation (CBA) in elderly patients based on available data in our registry. Methods The history of AF was assessed at admission. Additionally, all patients received echocardiographic examination and blood test. After a single trans-septal access and PV angiography PVI was performed using a 28-mm CBA. Mapping of PV signals before, during, and after each cryo application was performed with a 3F lasso catheter. The procedural endpoint after PVI was defined as complete elimination of all fragmented signals at the PV antrum with verification of entrance and exit block. Primary endpoint was first documented recurrence of AF, atrial tachycardia or atrial flutter (&amp;gt;30 sec.). All patients received a follow-up every 3 month within 1st year, once yearly thereafter and in case of symptoms. Seven days Holter ECG was recorded by every follow up. Results A total of 44 (39%) of enrolled patients were male, 48 (43%) suffered non- paroxysmal AF(nPAF), 93 (82%) had hypertension, CAD was diagnosed by 27 (24%), 28 (25%) had DM (Hb1AC &amp;gt; 6), Stroke/TIA was observed in 11 (10%). Median Age in elderly was 76 (75-78) y, BMI 25.77 (23.51-28.69), time since 1st diagnosis 40 (6-50) month, LA area index 11.36 (9.77-13.20), TAPSE 23 (19-26), GFR 74 (66-83) mL/min, LVEF 60 (57-62). A total of 44 patients (39%) reached endpoint within follow up of 20 (12-38) months. Univariate association with outcome was found by follows parameter: Time from 1st diagnosis &amp;gt; 3 y (HR = 3.22 (1.66-6.27), p=.001); LA area index (HR = 1.17 (1.03-1.32), p=.013); DM (HR = 1.89 (1.02-3.55), p=.042); nPAF (HR = 1.90 (1.04-3.47), p=.036). After multivariate analysis only time from 1st diagnosis &amp;gt; 3 y, (HR= 3.17 (1.62-6.16), p=.001 and nPAF (HR = 1.84 (1.01-3.36)), p=.048 were revealed to be predictive. The area under probability score calculated for these predictors was .731 (.638-8.25), p=.001. Follows complications were observed: 2 (2%) - pericard tamponades, 4 (4%) phrenicus nerve injury. Conclusion. PVI with cryo-balloon is effective for elderly patients providing freedom of arrhythmic events in 61% of patients. Longer history of AF over 3 years since 1st diagnosis was main predictor for post ablation recurrence. In elderly patients with shorter history of AF efficiency and safety of CBA is comparable with general population.

Intermediate term outcome after electrogram guided segmental ostial pulmonary vein isolation using an 8 mm tip catheter for paroxysmal atrial fibrillation

IntroductionPulmonary vein isolation (PVI) is the most widely used procedure for ablation in patients with paroxysmal atrial fibrillation (AF). Not withstanding recent advancements in this field, including sophisticated three-dimensional (3D) based imaging and advanced ablation catheters with contact force technology, many patients and healthcare systems in developing countries will not afford such an expensive therapeutic procedure. There are no data from India analyzing the efficacy of PVI for PAF using conventional mapping and ablation. In this article, we have summarized the intermediate term outcome following PVI in patients with PAF using electrogram-based mapping and a 8 mm tip ablation catheter. MethodA total of 42 consecutive patients who underwent PVI for symptomatic PAF not controlled with at least one antiarrhythmic drug were studied in a tertiary care institute from March 2011 to June 2018. Patients with rheumatic AF were excluded. The pulmonary vein (PV) anatomy was assessed by pulmonary angiography during the ablation procedure. Using conventional electrophysiologic mapping, a variable curve Lasso catheter placed in the PVs was used to guide the earliest site of breakthrough. The segmental ostial PVI was performed using a 8 mm tip radiofrequency (RF) ablation catheter. Elimination of all PV ostial potentials and complete entrance block into the PV were considered indicative of complete electrical isolation. Follow-up visits were scheduled at one, three, and six months after the procedure, and every six months thereafter. History, symptom review, clinical examination, and 12-lead ECG were performed at each follow-up. ResultsAt pre-discharge, 34 patients (81%) were in sinus rhythm, while eight patients (19%) continued to have atrial fibrillation. The age of the study population was 51.5 ± 11.7 yrs. The mean follow-up duration was 44 ± 21 months (range 6–84 months). The number of PVs isolated included one (five patients, 11.9%), two (20 patients, 47.6%), three (12 patients, 28.6%), and four (five patients, 11.9%). In 42 patients, a total of 101 PVs were isolated. The right superior PV (RSPV) was isolated in 37 patients, the left superior PV (LSPV) was isolated in 39 patients, the left inferior PV (LIPV) was isolated in 14 patients, and the right inferior PV (RIPV) was isolated in six patients. The procedure duration was 125 ± 29 min and the fluoroscopy time was 47 ± 13 min. The number of patients who remained in sinus rhythm at 1, 6, 12, and 24 months were 34 (81%), 32 (76%), 30 (71%), and 26 (62%), respectively. Two patients of these underwent repeat PVI, which was successful, and they had freedom from AF episodes. Complications were rare. One patient had a minor pericardial effusion, and one patient had transient sinus pauses, which were conservatively managed. ConclusionConventional RF ablation using PV potential-based mapping and ablation with 8 mm tip catheters is safe for patients with PAF. The intermediate term outcome is satisfactory and cost-effective in our setting with limited resources.

Locating Atrial Fibrillation Rotor and Focal Sources Using Iterative Navigation of Multipole Diagnostic Catheters

PurposeMulti-polar diagnostic catheters are used to construct the 3D electro-anatomic mapping of the atrium during atrial fibrillation (AF) ablation procedures; however, it remains unclear how to use the electrograms recorded by these catheters to locate AF-driving sites known as focal and rotor source types. The purpose of this study is to present the first algorithm to iteratively navigate a circular multi-polar catheter to locate AF focal and rotor sources without the need to map the entire atria.MethodsStarting from an initial location, the algorithm, which was blinded to the location and type of the AF source, iteratively advanced a Lasso catheter based on its electrogram characteristics. The algorithm stopped the catheter when it located of an AF source and identified the type. The efficiency of the algorithm is validated using a set of simulated focal and rotor-driven arrhythmias in fibrotic human 2D and 3D atrial tissue.ResultsOur study shows the feasibility of locating AF sources with a success rate of greater than 95.25% within average 7.56 ± 2.28 placements independently of the initial position of the catheter and the source type.ConclusionsThe algorithm could play a critical role in clinical electrophysiology laboratories for mapping patient-specific ablation of AF sources located outside the pulmonary veins and improving the procedure success.

Comparison of Outcomes Using the First and Second Generation Cryoballoon to Treat Atrial Fibrillation

Pulmonary vein isolation using cryoballoon ablation is an effective treatment for patients with atrial fibrillation. We sought to compare outcomes with the first and second generation cryoballoon, with the second generation balloon incorporating the Achieve Lasso catheter, in terms of freedom from symptomatic recurrence and major complications. The first 200 patients who underwent cryoballoon ablation with the first generation balloon were compared with the first 200 patients using the second-generation balloon. All patients had symptomatic atrial fibrillation and had failed at least one antiarrhythmic drug. The primary efficacy endpoint was freedom from symptomatic recurrence of atrial fibrillation (AF) after a single pulmonary vein isolation (PVI) procedure using the cryoballoon. The primary safety endpoint was major procedural complications. At 12 months, freedom from symptomatic AF after a single procedure in the first generation cohort was 64.3% compared with 78.6% in the second-generation cohort (p = 0.002). At 24 months, freedom from symptomatic AF in the first generation cohort was 51.3% compared with 72.6% in the second-generation cohort (p < 0.001). Procedural time (150 min vs 101 min; p < 0.001) and fluoroscopy time (32.5 min vs 21.4 min; p < 0.001) was lower in the second-generation group. The rate of major complications was comparably low in both groups. The second-generation cryoballoon was associated with improved freedom from symptomatic AF with reduction in procedure and fluoroscopy time, with a similar low rate of major complications.

Iterative navigation of multipole diagnostic catheters to locate repeating-pattern atrial fibrillation drivers.

IntroductionTargeting repeating‐pattern atrial fibrillation (AF) sources (reentry or focal drivers) can help in patient‐specific ablation therapy for AF; however, the development of reliable and accurate tools for locating such sources remains a major challenge. We describe iterative catheter navigation (ICAN) algorithm to locate AF drivers using a conventional circular Lasso catheter.Methods and ResultsAt each step, the algorithm analyzes 10 bipolar electrograms recoded at a given catheter location and the history of previous catheter movements to determine if the source is inside the catheter loop. If not, it calculates new coordinates and selects a new position for the catheter. The process continues until a source is located. The algorithm was evaluated in a computer model of atrial tissue with various degrees of fibrosis under a broad range of arrhythmia scenarios. The latter included slow and fast reentry, macroreentry, figure‐of‐eight reentry, and fibrillatory conduction. Depending on the initial distance of the catheter from the source and scenario, it took about 3 to 16 steps to localize an AF source. In 94% of cases, the identified location was within 4 mm from the source, independently of the initial position of the catheter. The algorithm worked equally well in the presence of patchy fibrosis, low‐voltage areas, fragmented electrograms, and dominant‐frequency gradients.ConclusionsAF repeating‐pattern sources can be localized using circular catheters without the need to map the entire tissue. The proposed algorithm has the potential to become a useful tool for patient‐specific ablation of AF sources located outside the pulmonary veins.

A novel real-time computational framework for detecting catheters and rigid guidewires in cardiac catheterization procedures.

PurposeCatheters and guidewires are used extensively in cardiac catheterization procedures such as heart arrhythmia treatment (ablation), angioplasty, and congenital heart disease treatment. Detecting their positions in fluoroscopic X‐ray images is important for several clinical applications, for example, motion compensation, coregistration between 2D and 3D imaging modalities, and 3D object reconstruction.MethodsFor the generalized framework, a multiscale vessel enhancement filter is first used to enhance the visibility of wire‐like structures in the X‐ray images. After applying adaptive binarization method, the centerlines of wire‐like objects were extracted. Finally, the catheters and guidewires were detected as a smooth path which is reconstructed from centerlines of target wire‐like objects. In order to classify electrode catheters which are mainly used in electrophysiology procedures, additional steps were proposed. First, a blob detection method, which is embedded in vessel enhancement filter with no additional computational cost, localizes electrode positions on catheters. Then the type of electrode catheters can be recognized by detecting the number of electrodes and also the shape created by a series of electrodes. Furthermore, for detecting guiding catheters or guidewires, a localized machine learning algorithm is added into the framework to distinguish between target wire objects and other wire‐like artifacts. The proposed framework were tested on total 10,624 images which are from 102 image sequences acquired from 63 clinical cases.ResultsDetection errors for the coronary sinus (CS) catheter, lasso catheter ring and lasso catheter body are 0.56 ± 0.28 mm, 0.64 ± 0.36 mm, and 0.66 ± 0.32 mm, respectively, as well as success rates of 91.4%, 86.3%, and 84.8% were achieved. Detection errors for guidewires and guiding catheters are 0.62 ± 0.48 mm and success rates are 83.5%.ConclusionThe proposed computational framework do not require any user interaction or prior models and it can detect multiple catheters or guidewires simultaneously and in real‐time. The accuracy of the proposed framework is sub‐mm and the methods are robust toward low‐dose X‐ray fluoroscopic images, which are mainly used during procedures to maintain low radiation dose.

Techniques for reducing air bubble intrusion into the left atrium during radiofrequency catheter and cryoballoon ablation procedures: An ex vivo study with a high-resolution camera

Air embolisms are serious complications during catheter ablation procedures. The aims of the present study were to determine when air bubbles enter the left atrium (LA) during catheter ablation procedures and to identify techniques that reduce air bubble intrusion. An exvivo study was performed to monitor air bubbles using a silicone heart model and a high-resolution camera. In total, 280 radiofrequency catheter and cryoballoon ablation processes were tested. Small and large air bubbles were often observed during catheter ablation processes. Many small air bubbles arose during sheath flushing at fast speeds (15 mL/2 s) (median bubble number [quartiles]: 35 [20-53] for SL0, 35 [23-44] for Agilis, and 98 [91-100] for FlexCath) and during initial cryoballoon inflation/freezing/deflation (34 [22-47]). Large (≥1.5 mm) air bubbles were observed during Lasso catheter insertion (1 [0-1]), cryoballoon insertion (2[1-2]), and initial inflation/freezing/deflation (1 [1-3]). Massive air bubbles were observed during Optima catheter insertion into the sheath using an inserter (10 [2-15]). Sheath flushing at slow speeds (15 mL/5 s) significantly reduced the number of air bubbles. Before cryoballoon insertion, temporary balloon inflation and air bubble removal from the inflated surface were most effective in reducing air bubble intrusions. Optima catheter insertion without an inserter significantly reduced large air bubble intrusion. Air bubbles entered the LA at specific times. Techniques such as sheath flushing at slow speeds, temporary cryoballoon inflation before insertion, inserting the Optima catheter without an inserter, and avoidance of negative pressure in the LA could reduce air bubble intrusion.

Accuracy of left atrial bipolar voltages obtained by ConfiDENSE multielectrode mapping in patients with persistent atrial fibrillation.

The ConfiDENSE™ module (Carto3 v4) allows rapid annotation of endocardial electrograms acquired by multielectrode (ME) mapping. However, its accuracy in assessing atrial voltages is unknown. Two ConfiDENSE™ left atrial voltage maps were created during continuous pacing in 20 patients undergoing catheter ablation for persistent AF using a ME lasso catheter and a contact force (CF) sensing ablation catheter. The automated tissue proximity indicator (TPI) filter was then applied to the ME map to yield a TPI map. Reference maps (RM) were created offline by a blinded observer by manually assessing all points against fidelity criteria. Bipolar voltages and proportion of low voltage points (<0.5mV) derived from the ME, CF, and TPI maps were compared with those derived from the RM. Note that 853 ± 365 points, 252 ± 184 points, and 144 ± 73 were collected for ME, TPI, and CF maps, respectively, and 429 ± 153 points were included in the RM. Voltages with CF and TPI maps were similar to those with RM (1.57 ± 0.47mV vs. 1.63 ± 0.31mV, P=0.57 and 1.50 ± 0.38mV vs. 1.63 ± 0.31mV, P=0.07, respectively), whereas ME maps showed a significantly lower mean voltage (1.00 ± 0.22mV, P<0.001). As compared to RM maps (17 ± 8%), low voltage points were significantly overestimated by the ME maps (50 ± 9% (P<0.001) and TPI maps (28 ± 13% (P<0.001), but not by the CF maps (22 ± 14%, P=0.17). Application of the TPI filter to ConfiDENSE maps significantly increases the quality of the voltage data, conserving a reasonable point density, but still overestimates low voltage points as compared to CF-sensing maps or maps reviewed manually.

ENTRAPMENT OF LASSO CATHETER IN CHIARI NETWORK: SUCCESSFUL EXTRACTION

Lasso catheter (LC) is commonly used for multiple electrode electrophysiological mapping of cardiac structures. Its entrapment has been reported in the mitral valve and tricuspid valve apparatus. A 57-year-old man with history of persistent atrial fibrillation (failed Dofetilide therapy) and

High incidence of focal and macro-reentrant arrythmias during repeat procedures after paroxysmal atrial fibrillation ablation using second-generation cryoballoon with no “bonus freeze” application

The second-generation cryoballoon (CB2) is effective in achieving pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF), however some repeat procedures (RP) were necessary. Describing clinical arrythmias during radiofrequency-based RP after PVI using CB2. Data from all consecutive patients requiring RP for symptomatic left atrial arrhythmias after PVI using CB2 28 mm with no “bonus freeze” application were analysed. A lasso catheter was used to check pulmonary veins’ (PV) electrical dissociation and map the clinical arrhythmia with a 3D mapping system, followed by ablation using radiofrequency (RF) energy. From January 2014 to December 2016, 31/270 patients (11.5%), mean age 56 ± 10 years, had RP for paroxysmal AF (24/31; 77.4%), persistent AF (1/31; 3.2%), atypical flutter (4/31; 12.9%) or left atrial tachycardia (2/31; 6.4%) after a median of 8 ± 8 months following PVI using CB2. Among them, 25 (80.6%) had at least one reconnected PV, but only 46/124 PVs (37.1%) were reconnected. Focal arrythmias was targeted in 12/31 (38.7%) patients, whereas left reentrant arryhthmias were found in 4/31 (12.9%) patients. Cavotricuspid isthmus ablation was performed in 7/31 (22.6%) patients due to induction of typical atrial flutter, typical atrioventricular nodal reentrant tachycardia was induced in one case (3,2%). The superior vena cava was isolated in 5/31 (16.1%) patients. Taking these complementary ablations into consideration, only 17/31 patients (54.8%) had PVI alone during those redo procedures using RF. After a 4-month follow-up, 14/24 (58.3%) patients were free from any symptom or recorded AF, reaching an overall 96.2% success rate after 2 or 3 procedures (only 4 patients). Atrial arrythmias’ recurrence can be related not only to PVs’ reconnection, but also to focal or reentrant atrial arrythmias. It supports the use of 3D-mapping-guided RF ablation for repeat procedures after CB2 ablation.