Nonfluoroscopic Mapping System Research Articles

Pulmonary vein isolation without fluoroscopy: results evaluation

Abstract Introduction From the outset, the use of Xray (XR) has been a critical component in both the guidance and development of arrhythmia ablation procedures. At present however, due to the complex nature of electrophysiology procedures, the use of XR in isolation is not sufficient to ensure procedural success. Subsequently, the use of non-fluoroscopic virtual mapping systems is essential. Currently, given the evolution of this technology and its essential nature for procedural guidance, it is worth asking whether the use of XR is indeed still necessary in the modern era. The objective of this study was to demonstrate that “zero-XR” ablation of complex arrhythmias such as atrial fibrillation is both possible and safe. Methods Between 2020 and 2021, a total of 116 patients admitted for pulmonary vein ablation were included in the study. Amongst these, 41 patients were prospectively included at our centre, in a protocol for point-by-point ablation of pulmonary veins without fluoroscopy, “zero-XR”. In addition to the non-fluoroscopic mapping system, the transseptal puncture was monitored by intracardiac ultrasound in all cases. The objective of the ablation was the complete isolation of the pulmonary veins. In some patients, at the discretion of the operator, the ablation of other substrates was added. For the remaining 75 patients in the study, the ablation was performed using conventional techniques without the limitation of the use of XR. The mean follow up was 12 months. Results The baseline characteristics of the patients, as well as the description of the procedure, are shown in the Table. There were no differences in the acute success rate or procedure time between the two groups. There was only one complication related to the procedure in the non-XR group consisting of pericardial effusion without cardiac tamponade. Regarding the recurrence rate at 12 months, it was higher in the group with fluoroscopy, without reaching statistical significance [n=0 in the group without fluoroscopy, n=2 (2.7%) in the group with fluoroscopy, p=0.15]. Conclusion In our series, point-by-point ablation of atrial fibrillation without fluoroscopy proved to be a safe and feasible technique, with similar success rates when compared to conventional procedures using XR. Funding Acknowledgement Type of funding sources: None.

Organization and procedures in contemporary catheter ablation centres: data from the 2018 Italian Catheter Ablation Registry.

This report describes the findings of the 2018 Italian Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC). The Italian Catheter Ablation Registry systematically collects data on the ablation procedures performed in Italy. Data collection was retrospective. A standardized questionnaire was completed by participating centres. We collected data on 15 714 catheter ablation procedures performed in Italy during 2018 in 94 electrophysiology centres. In most centres (75/94, 80%), a single electrophysiology laboratory was available, and a hybrid electrophysiology laboratory was available in 15% (14/94) of centres. In most (93%) centres, at least two electrophysiologists were involved in the catheter ablation procedures. In only 13 out of 94 (14%) electrophysiology laboratories, an anaesthesiologist assists every electrophysiology procedure; in most cases (74/94, 79%), an on-demand anaesthesiology service was available. On-site cardiothoracic surgery was reported in 43 out of 94 (46%) centres.Nonfluoroscopic navigation systems were available in most centres (88/94, 93%). Intracardiac echocardiography was used in 59 out of 94 (63%) electrophysiology laboratories. Atrial fibrillation (31%) was the most frequently treated ablation target, followed by atrioventricular nodal re-entrant tachycardia (20%) and cavo-tricuspid isthmus (15%). In 61.7% of all procedures, a 3D mapping system was used. In about one-third of procedures, a near-zero approach was performed. In most Italian electrophysiology centres, a single electrophysiology laboratory was available and at least two electrophysiologists were involved in the ablation procedures. An increasing number of procedures were performed by means of a nonfluoroscopic mapping system with a near-zero approach.

Ablation of Atrioventricular Nodal Reciprocating Tachycardia in Pregnancy with an Irrigated Catheter and Non-fluoroscopic Mapping System

We describe the case of a pregnant woman with an adenosinerefractory, poorly tolerated atrioventricular nodal reciprocating tachycardia (AVNRT), and successfully treated by RF ablation using an electroanatomical mapping system without radiation exposure. The procedure with the use of the navigation system associated with an irrigated catheter results in a possibility of definitive resolution of the tachycardia in absolute safety for the patient and for the fetus.

Zero x-ray cardiac resynchronization therapy device implantation guided by a nonfluoroscopic mapping system: A pilot study

Fluoroscopic guidance is the standard tool used in device implantation. This means that both the patient and the operator are exposed to radiation, which may sometimes be high. The possibility of single-lead permanent pacemaker implantation without fluoroscopy has already been demonstrated. The aim of our study was to investigate the feasibility and reliability of biventricular device implantation guided only by an electroanatomic navigation system. Sixty-one patients with heart failure underwent implantation of a cardiac resynchronization therapy (CRT) device with or without defibrillator (CRT-D; CRT-P). The procedure was performed with or without fluoroscopy guidance (Rx+; Rx0). In the latter case, the EnSite Velocity system was used; this system is able to reconstruct the anatomy and activation of the cardiac chambers by simultaneously collecting a "cloud" of anatomical points from multiple electrodes. Lead positioning was achieved in 24 of 26 patients undergoing CRT implantation without fluoroscopy (92% success). No complications were observed during the procedure and no catheter dislodgment occurred the day after the implantation or during 1-month follow-up. Procedure time progressively decreased from 136 minutes in the first case to 59 minutes in the last one, suggesting that operators gradually gained confidence while using the new technique. Our study demonstrates the feasibility, efficacy, and safety of lead positioning guided only by the nonfluoroscopic EnSite Velocity mapping system without the use of fluoroscopy in CRT-P or CRT-D implantation. The benefits in terms of significantly reduced fluoroscopy exposure are associated with technical and clinical advantages.

Catheter ablation of idiopathic fascicular ventricular tachycardia: The role of isolated diastolic potentials during mapping in sinus rhythm

Article history: Received 15 July 2015 Accepted 1 August 2015 Available online 3 August 2015 3.5 mm irrigated-tip catheter (NaviStar or SmartTouch Thermocool, BiosenseWebster) was used for mapping and ablation. The electroanatomic mapping of the left ventricle was performed using a threedimensional non-fluoroscopic mapping system (CARTO XP and CARTO 3, BiosenseWebster) via a retrograde transaortic approach. Intravenous heparin was administered throughout the procedure, targeting an activated clotting time around 300 s. A detailed substrate mapping during

Catheter ablation of idiopathic ventricular fibrillation using the CARTO 3 mapping system

Ventricular fibrillation in the absence of structural heart disease represents an important mechanism of sudden cardiac death. It is initiated by triggers originating in the distal Purkinje fibers, arising from either the right or the left ventricle. Catheter ablation of these triggers has the potential of terminating the arrhythmia and preventing recurrence. We present the case of an electrical storm in a 39-year old female patient with no cardiac past medical history, with recurrent episodes of idiopathic ventricular fibrillation, who was referred to our hospital for repeated episodes of syncope. The 12-lead ECG showed the presence of frequent ventricular premature beats (VPB), having a left-bundle branch block morphology and superior axis, with an “R on T” phenomenon, initiating non-sustained episodes of ventricular fibrillation. Using a three-dimensional, non-fluoroscopic mapping system (CARTO 3, Biosense Webster), the origin of the ventricular premature beat responsible for the initiation of VFib was identified and successfully ablated. Catheter ablation of idiopathic ventricular fibrillation using a 3-dimensional mapping system is a feasible therapeutic option for patients with this type of arrhythmia.

Nonfluoroscopic mapping reduces radiation exposure in ablation of atrial fibrillation

Radiofrequency catheter ablation (RFCA) of atrial fibrillation is an effective and definitive treatment. The methods used to guide RFCA have evolved over the years from a purely electrophysiological approach, in which anatomical lesions were guided solely by fluoroscopy and angiographic imaging of the pulmonary veins, to an approach guided by modern nonfluoroscopic electroanatomical mapping, integrated or not with computed tomography (CT). The aim of this study was, therefore, to compare radiation exposure of RFCA based on a fast three-dimensional nonfluoroscopic mapping system with 'traditional' mapping integrated with CT imaging. Thirty consecutive patients with atrial fibrillation who underwent RFCA were treated with two different approaches: 3D-Fast-Anatomical-Mapping and One-Map tool (FAM-One Map group, 21 patients) vs. 3D-Fast-Anatomical-Mapping integrated with CT images (MERGE-CT group, nine patients). Fluoroscopy time and radiation doses (expressed in milliGray) were compared. No statistically significant difference was detectable between FAM-One Map group and MERGE-CT group considering RFCA success rates and fluoroscopy times. Radiation exposure was higher in the MERGE-CT group (965 ± 138 mGy MERGE-CT group vs. 532 ± 216 mGy FAM-One Map group, P < 0.001) because of supplemental radiation exposures due to CT imaging (470 ± 126 mGy). A fast nonfluoroscopic electroanatomical mapping system may reduce radiation exposure in RFCA of atrial fibrillation, with preserved success rates.

Reduced fluoroscopy exposure during ablation of atrial fibrillation using a novel electroanatomical navigation system: a multicentre experience

Catheter ablation of atrial fibrillation (AF) focuses on pulmonary vein (PV) ablation with or without additional atrial substrate modification. These procedures require significant fluoroscopy exposure. A new 3D non-fluoroscopic navigation system (CARTO(®) 3 System, Biosense Webster, CA, USA) that allows precise location visualization of diagnostic and ablation catheters was evaluated for its impact on fluoroscopic exposure during AF ablation procedures. Two groups of patients were treated by our centres for drug refractory AF. One group was treated using the new CARTO(®) 3 system to guide catheter ablation (Group A, 117 patients). The other group was treated using the CARTO(®) XP system (Biosense Webster) 3 months previously (Group B, 123 patients). For both groups, circumferential PV ostia ablation was performed; PV isolation was validated using a circular catheter placed at each ostium. There was no difference in any clinical characteristics (age, sex, AF type, left atrium diameter and volume, and heart disease) among the two study groups. The mean number of PVs identified and isolated per patient was similar in both groups, as were the mean procedural duration and radiofrequency time. However, mean fluoroscopic time was significantly reduced in Group A (15.9±12.3 min) as compared with Group B (26±15.1 min) (P < 0.001). This multicentre observational study demonstrates a significant reduction of fluoroscopy exposure using a new 3D non-fluoroscopic mapping system to guide AF catheter ablation.

What is the origin of this arrhythmia?

Purpose The existence of inter-atrial epicardial connections bridging the two atria at different levels has well been described and their implication in some forms of supraventricular arrhythmias is a known fact. However, up to date, little data exists in the literature showing their role in the mechanisms of focal atrial tachycardias, providing at the same time clear electroanatomical and activation maps using a three-dimensional, non-fluoroscopic mapping system. Patients and methods We present the case of a 29-year-old woman with a focal atrial tachycardia with the origin in a pulmonary vein, manifested as a right atrial origin due to the conduction of the electrical impulse form the right inferior pulmonary vein (RIPV) to the postero-inferior right atrium (RA) via inter-atrial epicardial connections. Using a three-dimensional, non-fluoroscopic mapping system (CARTO, Biosense Webster), an RA activation map was created during tachycardia. Results Radiofrequency (RF) application at the earliest endocardial breakthrough site situated in the postero-inferior RA changed the right atrial depolarization sequence without terminating the arrhythmia. Subsequently, a left atrium activation map was created showing the earliest endocardial breakthrough site at the level of the RIPV ostium and RF application at this level abolished the atrial tachycardia. Conclusion Inter-atrial epicardial connections can be part of the substrate of some forms of supraventricular arrhythmias. Awareness of their existence is important to the electrophysiologist, since a better understanding of transseptal activation can avoid, in some cases, unnecessary RF applications at the level of the postero-septal right atrium, with a subsequent increase in procedural risk.

Low Risk of Major Complications Associated With Pulmonary Vein Antral Isolation for Atrial Fibrillation: Results of 500 Consecutive Ablation Procedures in Patients With Low Prevalence of Structural Heart Disease From a Single Center

To report the major complication rate associated with pulmonary vein antral isolation (PVAI) in a consecutive series of 500 patients from a single center. Catheter ablation for atrial fibrillation (AF) is an established procedure for refractory AF. However, the risk of major complications has been reported to range from 3.9% to 4.5% and continues to represent a cause for concern. We hypothesized that these studies may have overestimated the rate of major complications associated with PVAI in patients with a low prevalence of structural heart disease (SHD). Data were prospectively collected from 500 consecutive AF ablation procedures on 424 patients (mean age 55 ± 11 years, 79% men, paroxysmal AF-80% and persistent AF-20%, CHADS₂ scores of 0, 1, 2, 3 present in 64%, 28%, 7%, 1%, respectively), performed between July 2006 and September 2009. All procedures were performed under general anesthesia with intraoperative transesophageal echo. PVAI was performed using a nonfluoroscopic mapping system with an endpoint of PV isolation. Adjunctive left atrial ablation was performed in 21% of patients only. Major complications were defined from a compilation of those reported in 5 prior studies reporting complications. In 500 procedures, there were no instances of death, stroke/TIA, cardiac tamponade, atrioesophageal fistula, or PV stenosis. Major complications occurred in 4 procedures (0.8%): esophageal hematoma (TEE probe)--2; pharyngeal trauma--1; and retroperitoneal hematoma-1. AF ablation can be performed safely in young patients without structural heart disease with a low risk (<1%) of major complications when using a strategy of PVAI.

Radiofrequency catheter ablation of the slow pathway for atrioventricular nodal reentry in a patient with an obstructed inferior vena cava

A 51-year-old man with an obstructed inferior vena cava underwent successful slow pathway catheter ablation using a superior venous approach. Two central venous sheaths were introduced into the right internal jugular vein using different approaches (anterior and posterior), so the two sheaths located away from each other could prevent the catheters from 'sticking' to one another. The transseptal long sheath enabled a stable positioning of the ablation catheter. A nonfluoroscopic mapping system could reduce radiation exposure to the ablator. These techniques may be useful to overcome the disadvantages of the superior venous approach compared to the inferior venous approach.

Remote Magnetic Catheter Mapping and Ablation of Permanent Junctional Reciprocating Tachycardia in a Seven‐Year‐Old Child

Mapping and catheter ablation of permanent junctional reciprocating tachycardia (PJRT) in children can be challenging. Remote magnetic navigation may improve precise mapping and catheter stability during ablation, as well as reduce fluoroscopy time, especially in conjunction with a non-fluoroscopic mapping system. We report a case of PJRT ablation in a 7-year-old child using remote magnetic navigation. Mapping of the right atrium (RA) and the coronary sinus (CS) and catheter ablation were performed using remote magnetic navigation in conjunction with a non-fluoroscopic mapping system (NavX). We observed excellent catheter steering abilities and constant wall contact during ablation, allowing a short and safe procedure. Remote magnetic navigation may be used for mapping and ablation of PJRT in children.

Continuous Nonfluoroscopic Localization of the Esophagus During Radiofrequency Catheter Ablation of Atrial Fibrillation

Atrial-esophageal fistula formation is a dreaded complication of radiofrequency catheter ablation for atrial fibrillation. Esophageal localization is of potential value in avoiding lesion placement where the left atrium is juxtaposed to the esophagus. Twenty-seven patients underwent 33 pulmonary vein encirclement procedures. All the patients received general anesthesia with inhalational agents and either a fenestrated laryngeal mask airway or an endotracheal tube. A diagnostic electrophysiologic catheter was inserted into the esophagus, and a virtual esophageal tube was created using an electroanatomic mapping system. In all cases, the catheter was placed without difficulty and satisfactory virtual esophageal images were created. The catheter remained in the esophagus until the end of each ablation procedure. Esophageal catheter location during and after the ablation was compared with the initial location. Areas of close proximity between the left atrium and esophagus were easily identified. Change in esophageal location was not observed. Identification of esophageal proximity to the pulmonary veins allowed for identification of high-risk cases. In such cases, the planned procedure was modified to avoid esophageal injury (12 of 27 patients). (1) Real-time localization of esophageal position using a nonfluoroscopic mapping system during atrial fibrillation ablation is safe, practical, and straightforward. (2) Among patients who receive general anesthesia, esophageal position appears to be static, suggesting that one initial virtual image is sufficient for the duration of an ablation procedure.

Atrial Linear Lesions: Feasibility Using Cryoablation

Long linear lesions are created in the left atrium to modify the atrial substrate, thereby curing atrial fibrillation. The creation of long linear left atrial lesions using radiofrequency (RF) ablation is time consuming and difficult. Furthermore, it might result in significant complications. Cryoablation might overcome some of the disadvantages of RF ablation. Therefore, the aim of our study was to assess whether the creation of a long linear lesion is possible using cryotherapy. A right atrial septal linear lesion was created in six pigs (median weight: 50 kg; range: 40-60 kg). The ablation procedure was performed with a 7-F Freezor cryocatheter. The nonfluoroscopic mapping system LocaLisa was used as a navigation tool. At each point, freezing was maintained at the lowest attainable temperature (-75 degrees C) for 4 minutes. The CARTO system was used for the evaluation of the linear lesions. Furthermore, all animals were sacrificed immediately after the ablation procedure and a postmortem examination of the lesions was performed. Additionally, an analysis of the amplitudes of the intracardiac electrograms registered via the ablation catheter was performed before and after the ablation procedure. A right atrial septal linear lesion could be created successfully in all six pigs. For the performance of this ablation line, a median number of 16 cryoapplications (range, 11-26) was necessary. The amplitudes of the intracardiac electrograms registered via the ablation catheter decreased significantly after ablation. The CARTO bipolar voltage map revealed very low potentials along the ablation line and showed a sharply demarcated ablation area at the septum in all pigs. Further analysis of the CARTO map revealed an incomplete conduction block in all cases. Most of the pigs had a small gap close to the fossa ovalis. The postmortem examination of 2,3,5-triphenyl-tetrazolium chloride-stained specimens showed sharply demarcated lesions without any ulcerations. There were no major complications during the procedure. The creation of long linear lesions using cryoablation is feasible and safe. Lesion characteristics are different and more favorable than those created by RF. However, the aim of creating a transmural lesion and a complete conduction block remains an unsolved problem even with current cryoablation techniques. Nevertheless, growing experience and technical improvements might overcome some of the current limitations of this new technique.

Cardiac Three-Dimensional Magnetic Resonance Imaging and Fluoroscopy Merging

Modern nonfluoroscopic mapping systems construct 3D electroanatomic maps by tracking intracardiac catheters. They require specialized catheters and/or dedicated hardware. We developed a new method for electroanatomic mapping by merging detailed 3D models of the endocardial cavities with fluoroscopic images without the need for specialized hardware. This developmental work focused on the right atrium because of the difficulties in visualizing its anatomic landmarks in 3D with current approaches. Cardiac MRI images were acquired in 39 patients referred for radiofrequency catheter ablation using balanced steady state free-precession sequences. We optimized acquisition and developed software for construction of detailed 3D models, after contouring of endocardial cavities with cross-checking of different imaging planes. 3D models were then merged with biplane fluoroscopic images by methods for image calibration and registration implemented in a custom software application. The feasibility and accuracy of this merging process were determined in heart-cast experiments and electroanatomic mapping in patients. Right atrial dimensions and relevant anatomic landmarks could be identified and measured in all 3D models. Cephalocaudal, posteroanterior, and lateroseptal diameters were, respectively, 65+/-11, 54+/-11, and 57+/-9 mm; posterior isthmus length was 26+/-6 mm; Eustachian valve height was 5+/-5 mm; and coronary sinus ostium height and width were 16+/-3 and 12+/-3 mm, respectively (n=39). The average alignment error was 0.2+/-0.3 mm in heart casts (n=40) and 1.9 to 2.5 mm in patient experiments (n=9), ie, acceptable for clinical use. In 11 patients, reliable catheter positioning and projection of activation times resulted in 3D electroanatomic maps with an unprecedented level of anatomic detail, which assisted ablation. This new approach allows activation visualization in a highly detailed 3D anatomic environment without the need for a specialized nonfluoroscopic mapping system.

Microwave Ablation of an Ischemic Sustained Ventricular Tachycardia During Aortocoronary Bypass, Mitral Valve and Tricuspid Valve Surgery Guided by a Three-Dimensional Nonfluoroscopic Mapping System (CARTO)

Postinfarct patients with malignant ventricular tachyarrhythmias (VTs) are prone to an increased risk for sudden cardiac death and implantation of an internal cardioverter-defibrillator (ICD) often is recommended. In cases where the VTs are incessant or refractory to medical treatment, disruption of the macro-reentry circuit, which represents the arrhythmogenic substrate for postinfarct VTs, is a major therapeutical goal for electro-physiologists. The precise identification of this underlying macro-reentrant circuit depends on conventional mapping techniques (i.e. diastolic potentials, entrainment) and more recently by a three-dimensional non-fluoroscopic electro-anatomical mapping system (CARTO), which integrates anatomical and electrophysiological information to reconstruct a three-dimensional activation and propagation map of the relevant VT. This reports describes on a patient with recurrent, drug-refractory, hemodynamically stable monomorphic VTs on the basis of a 2-vessel coronary artery disease, reduced left ventricular ejection fraction, who was scheduled for coronary artery bypass graft operation combined with mitral valve replacement and reconstruction of the tricuspid valve. Preoperatively, the underlying mechanism of the VT was identified by CARTO mapping with a slow conduction zone and a wide exit site at the inferoapico-basal portion of the left ventricle. In close cooperation between the cardiologists and the surgeons the decision for a simultaneous ablation approach during the subsequent operation was made. Successful ablation of the VT using microwave energy was confirmed by non-inducibility of the VT in the perioperative electrophysiologic study. This case report highlights the use of CARTO mapping to identify postinfarct VTs as well as the application of microwave energy as a useful tool to cure postinfarct ventricular arrhythmias.

Differences in success of repeat ablation procedure for recurrent atrial fibrillation after two different ablation strategies: Results from a prospective randomized study comparing pulmonary vein isolation versus circumferential pulmonary vein ablation

Minnesota.) non-fluoroscopic mapping system has the potential to reduce X-ray exposure during electrophysiological procedures. This is the first prospective randomised controlled study to compare radiation exposure, safety and cost between conventional, electroanatomical (Carto) and high frequency electrical field (NavX) mapping techniques. Methods: All patients undergoing catheter ablation (except AV node and AF ablation) were randomised to a Carto, NavX or conventional mapping procedures. Immediate procedural success was defined using standard criteria (eg bi-directional block for typical atrial flutter, non inducibilty of AVNRT/AVRT etc). All patients were seen 6 weeks following the procedure and success defined as both freedom from symptoms and no documented recurrence of any arrhythmia other than ectopy. Procedure costs included diagnostic and ablation catheters, Carto reference patch and the complete NavX kit. All costs are the published UK list prices. Statistical comparison was made against conventional procedures. Results: Eighty-nine patients (54% men) aged 48 17 (mean SD) were randomised. 5 patients were withdrawn as no arrhythmia could be induced. There were no significant differences between Carto and NavX in any variable. Conclusion: For all catheter ablation procedures, procedure duration and outcome are similar for Carto, Navx and conventional procedures. Both Carto and NavX are associated with reduced fluoroscopy time and radiation dose compared to conventional x-rays but at an increased cost. The costs of NavX are likely to reduce as we become more comfortable using fewer catheters for EP procedures.

Catheter location trial: A prospective randomised comparison of Carto, NavX and conventional for catheter ablation

Introduction: The EnSite NavX (Endocardial Solutions, Inc. St Paul, Minnesota.) non-fluoroscopic mapping system has the potential to reduce X-ray exposure during electrophysiological procedures. This is the first prospective randomised controlled study to compare radiation exposure, safety and cost between conventional, electroanatomical (Carto) and high frequency electrical field (NavX) mapping techniques.

Atrial linear lesions: Feasibility using cryoablation

Although focal ablation has become an accepted approach to treat AF it is associated with a high arrhythmia recurrence rate. Therefore, the concept of creating linear lesions in the right or left atrium is of great interest as well. However, the creation of long linear lesions using RF ablation is extremely difficult. Therefore, the aim of our study was to asses whether the creation of a long linear lesion in the right atrium is possible using cryotherapy. A right atrial septal linear lesion was performed in 6 pigs. The ablation procedure was performed with a 7 F Freezor cryocatheter (CryoCath Technologies). The non-fluoroscopic mapping system LocaLisa was used as a navigation tool. The CARTO system was used for the evaluation of the linear lesions. Furthermore, all animals were sacrificed immediately after the ablation procedure and a post-mortem examination of the lesions was performed. Additionally, an analysis of the amplitudes of the intracardiac electrograms registered via the ablation catheter was performed before and after the ablation procedure. A right atrial septal linear lesion could be performed successfully in all 6 pigs. For the performance of this ablation line, a median number of 16 (range: 15) cryoapplications was necessary. The amplitudes of the intracardiac electrograms registerd via the ablation catheter decreased significantly after the ablation. Similarly, a CARTO bipolar voltage map revealed very low potentials among the ablation line in all pigs. There was a sharply demarcated ablation line in all pigs. Further analysis of the CARTO maps revealed an incomplete conduction block in all pigs. This was mostly due to a gap in the area of the fossa ovalis. The creation of long linear lesions using cryoablation is feasible and safe. Lesion characteristics are different and more favourable in comparison to RF-lesions. However, lesion transmurality was lacking especially in the area of the fossa ovalis.

Use of a New Non‐Fluoroscopic Three‐Dimensional Mapping System in Type I Atrial Flutter Ablation

We studied 40 patients who underwent cavo-tricuspid isthmus ablation for typical counterclockwise atrial flutter with cooled tip catheters between 2001 and 2003. Complete bi-directional isthmus block was created in all patients. A new, three-dimensional (3D), non-fluoroscopic mapping system was used in 20 patients (test group), and conventional fluoroscopy in 20 others (conventional group), using anatomic and electrophysiologic criteria in both groups. We measured the total procedure, ablation procedure, and overall fluoroscopy times, and the total number of radiofrequency (RF) applications delivered in the two groups. The overall fluoroscopy time was shorter in the test group (mean 8.8 minutes, range 2-17 minutes) than the conventional group (29.7 minutes, range 12-57 minutes; P < 0.001). Though the overall procedure time was similar in both groups (92.5 +/- 28.6 minutes vs 106.5 +/- 20.9 minutes; P = 0.067) the ablation duration (25.1 +/- 6.6 minutes versus 43.3 +/- 19.6 minutes; P = 0.0051) and the total RF applications (10.6 +/- 9.4 versus 16.4 +/- 9.4; P = 0.044) were smaller in the test group. The use of a new, 3D non-fluoroscopic mapping system markedly reduced the fluoroscopy exposure during typical atrial flutter ablation. It was also associated with a significant reduction in ablation time and in the number of RF applications. Since atrial flutter ablation is one of the most frequently performed procedures, this system may significantly reduce the overall amount of radiation exposure in high-volume laboratories.