LocaLisa catheter navigation reduces fluoroscopy time and dosage in ablation of atrial flutter: a prospective randomized study

INTRODUCTION: Catheter ablation has become a well-established therapy for isthmus-dependent right atrial flutter (AFL). Recently, mapping and ablation of AFL have been performed using sophisticated three-dimensional mapping systems, such as electroanatomic and noncontact mapping systems. The LocaLisa system enables nonfluoroscopic navigation of intracardiac electrode catheters based on impedance changes related to catheter movements in transthoracic current fields. The aim of this randomized prospective study was to compare the efficacy of the LocaLisa system with the conventional mapping/ablation approach for radiofrequency ablation of AFL. METHODS AND RESULTS: Fifty consecutive patients with AFL (39 men and 11 women; age 65 +/- 10 years) were studied. The patients were randomly assigned to undergo radiofrequency ablation guided by a conventional fluoroscopy-based approach (24 patients) or by the LocaLisa system (26 patients). Ablation success rate and documentation of bidirectional isthmus block were 100% in both groups. Compared with fluoroscopy-guided approaches, LocaLisa-guided procedures demonstrated a reduction in total fluoroscopy time from 15.9 +/- 10.6 minutes to 7.5 +/- 6.5 minutes (P < 0.005). Total fluoroscopy dosage was reduced from 21.0 +/- 19.8 to 8.7 +/- 9.5 Gycm2 (P < 0.05). Fluoroscopy time required for ablation was significantly shortened in the LocaLisa group (2.6 +/- 2.6 min) compared with the conventional approach group (11 +/- 10 min, P < 0.0005). In 9 (35%) of 26 patients, the ablation could be performed with a fluoroscopy time < or = 1 minute. There were no significant differences with regard to the number of radiofrequency applications, fluoroscopy time needed for diagnostic reasons, total procedure time, or other ablation data. CONCLUSION: Compared with the conventional approach, the LocaLisa system significantly reduces the fluoroscopy times needed for ablation of typical AFL.     

Comparison between anatomical and integrated approaches to atrial fibrillation ablation: adjunctive role of electrical pulmonary vein disconnection

INTRODUCTION: The aim of this study was to compare the outcome of anatomical pulmonary vein (PV) radiofrequency (RF) ablation with that of an integrated approach (anatomical with electrophysiological confirmation of PV disconnection). METHODS: Sixty consecutive patients affected by drug-refractory paroxysmal (39), persistent (13), and permanent (8) atrial fibrillation (AF) were assigned to an anatomical (group A: 30 patients; 25 male, 5 female, mean age: 55 +/- 7 years) or integrated approach (group B: 30 patients; 26 male, 4 female, mean age: 52 +/- 9 years). In all cases, RF ablation was performed by means of the Carto system in order to anatomically create circumferential lines around PVs. In group B, the persistence of PV potentials was then assessed with a multipolar circular catheter. If PV potentials persisted, RF pulses targeting the electrophysiological breakthroughs were delivered to disconnect PVs. RESULTS: Total procedure duration, fluoroscopy time, and RF delivery time were similar in both groups: 227 +/- 43, 50 +/- 23, and 43 +/- 16 minutes (group A); 232 +/- 32, 55 +/- 15, and 42 +/- 10 minutes (group B), respectively (ns). One asymptomatic PV stenosis and one pericardial effusion occurred in group A and B, respectively. After 15.4 +/- 7.4 months, 17 (57%) group A patients and 25 (83%) group B patients were in stable sinus rhythm (P = 0.02) (RR 1.78; 95% CI: 1.7-2.9). CONCLUSIONS: PV ablation by means of an integrated anatomical and electrophysiological approach seems more effective than a purely anatomical RF ablation approach. Electrophysiological confirmation of PV disconnection could be a useful marker of successful RF treatment of AF.     

电解剖标测和磁共振影像融合技术指导导管消融心房颤动的有效性研究

目的探讨三维电解剖标测（CARTO）系统重建图像和预先取得的磁共振影像融合后指导心房颤动（房颤）导管消融的有效性。方法从2005年9月至2006年9月对连续100例药物治疗无效的房颤患者行导管消融治疗,基本策略均为在CARTO系统指导下进行环肺静脉线性消融并实现电学隔离。随机分为2组,每组50例。第1组为术前配准组,在消融开始前即进行影像配准并融合,并在此融合影像指导下进行导管消融,消融结束后进行再次融合;第2组为术后配准组,在单纯CARTO技术指导下消融,消融结束后才进行影像配准并融合。最后比较两组的消融结果并评估消融过程中的差异。结果环肺静脉消融结束后,第1组左心房三维磁共振表面重建影像至电解剖标测图像各点平均距离为（1．6±0．7）mm,消融线上平均标记位点（75±27）个,平均X线透视时间（31±21）min;第2组的上述指标分别为（2．1±1．3）mm、（98±38）个、（55±29）min。以上组间比较差异都有统计学意义。将实际消融线与预定消融线比较,第2组中有组间差异的偏差区域分别是左侧肺静脉前庭顶部（15例）、底部（11例）、前下缘（23例）、前上缘（24例）和右侧肺静脉前庭后上缘（12例）、底部（10例）、前下缘（15例）。结论影像融合技术指导导管消融可提高准确性,并可减少X线透视时间及消融点数。     

Favorable effect of pulmonic vein isolation by partial circumferential ablation on ostial flow velocity

OBJECTIVES: The aim of this study was to determine the effect of electrical isolation of pulmonic vein (PV) on flow velocity. BACKGROUND: We report our experience with electrical isolation of PV by partial circumferential ablation and its effect on ostial peak flow velocity as assessed by phased-array ultrasound catheter imaging. METHODS: Sixty-two patients participated in the study. Magnetic electroanatomic mapping, ultrasound catheter imaging, and Lasso mapping catheter were used. Electrical isolation was achieved by delivering radiofrequency ablation (RFA) lesions proximal to Lasso mapping catheter bipoles showing PV entry. Following this, the number of RFA lesions/PV and their segment-wise distribution (maximum 4/PV) were assessed. RESULTS: Fifty right superior, 51 left superior, 32 left inferior, and 17 right inferior PVs were isolated. RFA involved 4 segments in 42 PVs, 3 segments in 61 PVs, and 90% reduction in AF burden, either with or without previously ineffective antiarrhythmic agents, was achieved in 54 patients (87%). CONCLUSIONS: In the majority of PVs (72%), electrical isolation can be achieved by partial circumferential ablation (targeting 相似文献   

Use of a Non-Fluoroscopic Catheter Navigation System for Pulmonary Vein Isolation

INTRODUCTION: Pulmonary vein (PV) isolation is commonly performed by using separate mapping and ablating catheters. Steering the ablation catheter to the target electrodes on the mapping catheter can be difficult and time consuming under fluoroscopic guidance. We investigated the use of a non-fluoroscopic catheter navigation system to facilitate radiofrequency pulmonary vein isolation. METHODS: The LocaLisa non-fluoroscopic catheter navigation system was used during PV isolation in 21 patients. Eleven control patients underwent the procedure under fluoroscopic guidance alone. PV isolation was performed by mapping the veins with a 10 or 20 pole circular mapping catheter and ablating at targeted mapping bipoles with a separate ablation catheter. RESULTS: The electrodes of both catheters were visualized in 3 dimensional virtual space by LocaLisa. There were no clinical differences between the LocaLisa and control patients. During mapping, electrical artifacts were produced on specific mapping electrodes by contact with the ablation catheter. A blinded observer using LocaLisa correctly identified the mapping electrodes being contacted by the ablation catheter in 368 of 398 (92%) of cases. Total fluoroscopic time was reduced in the LocaLisa group (72 +/- 29 minutes) compared to the control group (102 +/- 37 minutes, p = 0.02). There were no differences between the groups in total procedure times, number of lesions given, complications or long term procedural success (all p > 0.45). CONCLUSIONS: The LocaLisa catheter navigation system accurately identifies the position of an ablation catheter relative to the target electrodes on a circular mapping catheter. The system also significantly reduces total fluoroscopic time for PV isolation.     

三维标测系统指导下环肺静脉消融治疗心房颤动

目的 探讨三维标测系统指导下环肺静脉消融治疗心房颤动的安全性和有效性.方法 阵发性心房颤动92例和持续性或永久性心房颤动36例,接受环肺静脉消融术.采用Carto电解剖标测系统,进行环肺静脉左心房线性消融,消融终点为肺静脉电隔离.手术结束时对心律仍为心房颤动者行同步直流电心脏复律.结果 完成"解剖学"环形消融线256条,其中58.6%达到电隔离肺静脉的终点,经寻找缝隙补充消融后最终248条(96.9%)消融线达到终点.手术时间(231±45)min、X线曝光时间(42±13)min和放电时间(66±17)min.术后随访平均10个月,无复发101例(78.9%).接受了再次手术15例,心内电生理检查证实14例有左心房-肺静脉传导,射频消融成功并随访30～270 d,两次射频消融术后总成功率为87.5%,其中阵发性心房颤动成功率为93.0%,持续性或永久性心房颤动为76.7%.并发症发生率为6.2%,包括心包填塞2例、小脑梗死2例、股静脉穿刺部位血肿1例和左侧大量血胸1例,经治疗后均痊愈.结论 以肺静脉电隔离为目标的环肺静脉消融术治疗心房颤动有效和安全.     

Usefulness of a new radiofrequency thermal balloon catheter for pulmonary vein isolation: a new device for treatment of atrial fibrillation

INTRODUCTION: A rapidly firing or triggered ectopic focus located within a pulmonary vein (PV) or close to the PV ostium could induce atrial fibrillation (AF). The aim of this study was to evaluate the efficacy and safety of a radiofrequency thermal balloon catheter for isolation of the PV from the left atrium (LA). METHODS AND RESULTS: Twenty patients with drug-resistant paroxysmal AF were treated by isolating the superior PVs using an RF thermal balloon catheter. Using a transseptal approach, the balloon, which had an inflated diameter 5 to 10 mm larger than that of the PV ostium, was wedged at the LA-PV junction. It was heated by a very-high-frequency current (13.56 MHZ) applied to the coil electrode inside the balloon for 2 to 3 minutes, and the procedure was repeated up to four times. The balloon center temperature was maintained at 60 degrees to 75 degrees C by regulating generator output. Successful PV isolation was achieved in 19 of the 20 left superior PVs and in all 20 of the right superior PVs and was associated with a decrease in amplitude of the ostial potentials. Total procedure time was 1.8 +/- 0.5 hours, which included 22 +/- 7 minutes of fluoroscopy time. After a follow-up period of 8.1 +/- 0.8 months, 17 patients were free from AF, with 10 not taking any antiarrhythmic drugs and 7 taking the same antiarrhythmic agent as before ablation. Electron beam computed tomography revealed no complications, such as PV stenosis at ablation sites. CONCLUSION: The PV and its ostial region can be safely and quickly isolated from the LA by circumferential ablation around the PV ostia using a radiofrequency thermal balloon catheter for treatment of AF.     

Ventricular tachycardia ablation guided by LocaLisa system in patients with structural heart disease

INTRODUCTION: The ablation of ventricular tachycardia is limited by a number of factors that reduce the effectiveness of this intervention in patients with structural heart disease compared to other types of arrhythmia. Recent years have seen the development of several nonfluoroscopic navigation techniques that facilitate the mapping of complex arrhythmogenic substrates. One such technique, the LocaLisa system, has not previously been tested for the ablation of ventricular tachycardia. PATIENTS AND METHOD: A total of 32 patients with structural heart disease were treated at our center with ablation for sustained ventricular tachycardia. In 10 patients the LocaLisa system was used to visualize the catheters during the procedure. We compared the results in the LocaLisa group with those in a control group of 22 patients treated with conventional fluoroscopy-guided ablation. RESULTS: The success rate of ablation was 75% (9/12 procedures) in the LocaLisa group and 68% (17/25 procedures) in the control group (P=NS). In the LocaLisa group, mean total duration of the procedure (243 +/- 84), duration of ablation (86 +/- 56) and fluoroscopy time (46 +/- 19) did not differ significantly from those in the control group (244 +/- 72 min, 79 +/- 58 min, and 43 +/- 27 min, respectively). In the LocaLisa group the trend toward greater hemodynamic intolerance in ventricular tachycardia approached significance (42% in the LocaLisa group vs 24% in the control group, P=.05) and the number of mapping procedures performed during sinus rhythm was significantly higher in the former (33% in the LocaLisa group vs 4% in the control group, P=.03). With the LocaLisa system it was possible to locate and reposition the ablation catheter accurately at the target endocardial sites, as confirmed by electrographic recordings and fluoroscopic verification. CONCLUSIONS: The LocaLisa system helps to delineate the reentry circuit and facilitates accurate catheter repositioning in patients with structural heart disease and ventricular tachycardia.     

Effects of circumferential ostial radiofrequency lesions on pulmonary vein activation recorded with a multipolar basket catheter

AIMS: Two different ablation procedures are performed to cure patients of atrial fibrillation (AF): (1) the electrophysiological pulmonary vein (PV) isolation, and (2) the anatomical circumferential ablation of all four PV ostia. The aim of this study was to determine the effects of circumferential radiofrequency lesions around the ostia on PV activation. METHODS AND RESULTS: In 34 patients with drug refractory paroxysmal (N = 22) or persistent (N = 12) AF a 31-mm basket catheter (BC) was introduced transseptally in the PVs. After creating a circumferential ablation line around the PV ostia using a nonfluoroscopic 3D-navigation system, electrical isolation was achieved in 46% of the PVs, and prolongation of conduction time (+39 +/- 34 ms) was observed in 30%. PVs with persistent conduction (54%) were isolated by ablating the remaining conduction pathways using the BC. At 12 months follow-up, 62% of the patients were in stable sinus rhythm without antiarrhythmic drug therapy. Six patients had developed left atrial flutter. CONCLUSIONS: Anatomically guided, circumferential lesions around the PV ostia resulted in isolation in only 46% of the veins. At 12 months, 62% of the patients were free of AF without antiarrrhythmic drug treatment, however, 6 patients (18%) developed left atrial flutter.     

Nonfluoroscopic Three‐Dimensional Mapping for Arrhythmia Ablation: Tool or Toy?

INTRODUCTION: Conventional mapping and ablation rely on fluoroscopy, which can result in imprecise positioning of the ablation catheter and long fluoroscopic exposure times. We evaluated a nonfluoroscopic three-dimensional mapping system, termed CARTO, and compared the results of ablation using this technique with those of conventional mapping. METHODS AND RESULTS: We compared the results of 88 arrhythmia ablations (79 patients) using CARTO with 100 ablations (94 patients) using the conventional technique. The ablations were separated into four groups: (1) AV nodal reentrant tachycardia (AVNRT); (2) atrial tachycardia/flutter; (3) ventricular tachycardia (VT); and (4) bypass tract tachycardia. We compared the success rate, complications, and fluoroscopy and procedure times. The ablation outcomes were excellent and comparable in all four types of the arrhythmias between the two techniques. Major complications included one cardiac tamponade in each group and one second-degree AV block in the conventional group. Fluoroscopy time was shorter using the CARTO technique: 10+/-7 versus 27+/-15 minutes for AVNRT (P < 0.01), 18+/-17 versus 44+/-23 minutes for atrial tachycardia and flutter (P < 0.01), 15+/-12 versus 34+/-31 minutes for VT (P < 0.05), and 21+/-14 versus 53+/-32 minutes for bypass tract tachycardia (P < 0.01). Procedure times were similar except for the bypass tract patients, which was shorter in the CARTO group, 4+/-1.3 versus 5.5+/-2.5 hours (P < 0.01). CONCLUSION: The electroanatomic three-dimensional mapping technique reduced fluoroscopy time and resulted in excellent outcome without increasing the procedure time.     

Reduction of fluoroscopy exposure and procedure duration during ablation of atrial fibrillation using a novel anatomical navigation system.

AIMS: Catheter ablation of atrial fibrillation (AF) is centred on pulmonary vein (PV) ablation with or without additional atrial substrate modification. These procedures may be prolonged with significant fluoroscopy exposure. This study evaluates a new non-fluoroscopic navigation system during ablation of AF. METHODS AND RESULTS: Seventy-two patients undergoing catheter ablation of symptomatic drug refractory AF were prospectively randomized to ablation with (n=35; study group) or without (n=37; control group) non-fluoroscopic navigation. PV isolation was performed in all patients. In patients with persistent or inducible sustained AF after PV isolation linear ablation was performed by joining the superior PVs. PV isolation was achieved in all patients; fluoroscopy (15.4+/-3.4 vs. 21.3+/-6.4 min; P<0.001) and procedural (52+/-12 vs. 61+/-17 min; P=0.02) durations were significantly reduced in the study group. Linear block was achieved in 37 of the 39 patients; with a significant reduction in fluoroscopy (5.6+/-2.2 vs. 9.9+/-4.8 min; P=0.003) and procedural (14.7+/-5.5 vs. 26.6+/-16.9 min; P=0.007) durations in the study group. After a follow-up of 6.9+/-2.9 months (range 3-10), 26 (74%) patients in the non-fluoroscopic navigation group and 29 (78%) patients in the control group were arrhythmia-free after the first procedure. CONCLUSION: This prospectively randomized study demonstrates significant reduction of fluoroscopy exposure and procedural duration using supplementary non-fluoroscopic imaging system for AF ablation.     

Endocardial impedance mapping during circumferential pulmonary vein ablation of atrial fibrillation differentiates between atrial and venous tissue

BACKGROUND: Circumferential pulmonary vein ablation (CPVA) is an effective treatment for atrial fibrillation (AF). Accurate left atrial (LA) mapping is essential for creating lesions at the LA-pulmonary vein (PV) junction, avoiding PV stenosis. OBJECTIVES: The purpose of this study was to establish whether endocardial impedance varies within the LA and PVs and whether it is a useful tool for mapping and ablation. METHODS: Pilot Phase: Three-dimensional LA maps were created using CARTO. Impedance (Z) was measured using a radiofrequency generator at multiple points in the LA, PV ostia (PVO), and deep PVs in 79 patients undergoing their first AF ablation (group 1) and 29 patients undergoing repeat CPVA (group 2). Prospective Phase: In an additional 20 patients, using pilot phase data, one operator defined catheter tip location as either LA or PVO based on CARTO and fluoroscopy. A second operator blinded to CARTO simultaneously did the same based on impedance at 15 +/- 4 points per patient. RESULTS: Group 1: Z(LA) was 99.4 +/- 9.0 omega. Z(PVO) was higher (109.2 +/- 8.5 omega), rising further as the catheter advanced into deep PV (137 omega +/- 18). Z(PVO) differed from Z(LA) by 9 +/- 4 omega. Group 2 had a lower Z(LA) and Z(PVO) compared with group 1 (P <.05). Impedance monitoring differentiated between LA and PVO, with 91% specificity and sensitivity, 96% positive predictive value, and 81% negative predictive value. At 3-month follow-up, no patients had evidence of PV stenosis on magnetic resonance imaging. CONCLUSION: Impedance mapping reliably identifies the LA-PV transitional zone, facilitating AF ablation, and its use is associated with a low incidence of PV stenosis.     

环肺静脉线性消融电学隔离肺静脉治疗100例心房颤动临床评价

目的探讨三维标测系统和单环状标测电极指导下行环肺静脉线性消融电学隔离肺静脉治疗心房颤动(房颤)的可行性和有效性。方法自2004年4月至2005年1月共对连续100例症状明显、发作频繁、抗心律失常药物治疗无效的房颤患者进行了在CARTO系统(76例)或EnSite-NavX系统(24例)指导下的环肺静脉线性消融术,消融终点为双侧肺静脉的彻底电学隔离。结果100例患者共完成200个环形消融环,肺静脉电学隔离率为95.0%。操作时间150～365(240±65)min,X线时间为23～61(37±12)min。其中8例(8.0%)复发患者接受了再次导管消融。随访5.5～12(10.2±5.7)个月,累计无房性快速心律失常率为85.0%。术后1、2、3、4、5、6个月时无房性快速心律失常率分别为66.0%、82.0%、87.0%、85.0%、85.0%、88.6%。并发症包括1例心脏压塞,经保守治疗后康复,1例患者出现无症状性肺静脉狭窄。结论在三维标测系统指导下,环肺静脉线性消融电学隔离肺静脉治疗房颤安全有效。     

在心房颤动持续过程中行肺静脉电学隔离术的可行性

探讨在心房颤动 (简称房颤 )持续过程中行肺静脉电学隔离术的可行性。 9例在导管消融术中房颤持续发作的房颤患者 ,根据肺静脉环状标测电极导管记录的肺静脉激动特征采用 2种方法进行肺静脉开口部的消融 :①肺静脉激动有序且有一种或多种固定的激动顺序 ,采用射频导管消融环状电极记录的最早的激动部位 ;②肺静脉激动无序或无明确的激动顺序 ,首先使用超声球囊导管消融 ,如未达终点再加用射频导管消融。 2种方法的消融终点均为肺静脉电学隔离。总计对 31根肺静脉进行了消融 ,其中 2 8根在房颤心律下消融。房颤心律下电隔离肺静脉的成功率为 92 .9% (2 6根 )。总操作时间和X线透视时间分别为 1 38± 2 1min和 38± 9min。本组无肺静脉狭窄及其他并发症。随访 6 .3± 2 .9(3～ 1 1 )个月后 ,4例 (44.4% )患者无房颤发作 (无需药物 )。结论 :在房颤持续过程中行肺静脉电学隔离术方法可行 ,且较为安全 ;联用超声球囊消融和射频消融对于房颤发作过程中无序或无明确激动顺序的肺静脉具有较好的电学隔离效果。     

Initial experience in the use of integrated electroanatomic mapping with three-dimensional MR/CT images to guide catheter ablation of atrial fibrillation

INTRODUCTION: No prior studies have reported the use of integrated electroanatomic mapping with preacquired magnetic resonance/computed tomographic (MR/CT) images to guide catheter ablation of atrial fibrillation (AF) in a series of patients. METHODS AND RESULTS: Sixteen consecutive patients with drug-refractory AF underwent catheter ablation under the guidance of a three-dimensional (3D) electroanatomic mapping system (Carto, Biosense Webster, Inc., Diamond Bar, CA, USA). Gadolinium-enhanced MR (n = 8) or contrast-enhanced high-resolution CT (n = 8) imaging was performed within 1 day prior to the ablation procedures. Using a novel software package (CartoMerge, Biosense Webster, Inc.), the left atrium (LA) with pulmonary veins (PVs) was segmented and extracted for image registration. The segmented 3D MR/CT LA reconstruction was accurately registered to the real-time mapping space with a combination of landmark registration and surface registration. The registered 3D MR/CT LA reconstruction was successfully used to guide deployment of RF applications encircling the PVs. Upon completion of the circumferential lesions around the PVs, 32% of the PVs were electrically isolated. Guided by a circular mapping catheter, the remaining PVs were disconnected from the LA using a segmental approach. The distance between the surface of the registered 3D MR/CT LA reconstruction and multiple electroanatomic map points was 3.05 +/- 0.41 mm. No complications were observed. CONCLUSIONS: Three-dimensional MR/CT images can be successfully extracted and registered to anatomically guided clinical AF ablations. The display of detailed and accurate anatomic information during the procedure enables tailored RF ablation to individual PV and LA anatomy.     

Electrogram polarity reversal as an additional indicator of breakthroughs from the left atrium to the pulmonary veins

OBJECTIVES: We assessed the anatomical distribution and electrogram characteristics of breakthrough from the left atrium (LA) to the pulmonary veins (PVs). BACKGROUND: Localization of LA-PV breakthrough is an important technique for PV ablation in patients with atrial fibrillation (AF). METHODS: A total of 157 patients with paroxysmal AF underwent PV disconnection guided by mapping with a circumferential 10-electrode catheter. Radiofrequency (RF) current was delivered ostially at the site(s) of earliest activation (113 patients) or electrogram polarity reversal defined by opposite polarity across adjacent bipoles (44 patients). Breakthrough sites were proved by changes in pulmonary vein potential activation sequence occurring as a result of localized RF delivery and were classified into four segments around the ostium (top, bottom, anterior, posterior). Results of mapping and ablation were compared between the two groups. RESULTS: A total of 99% of 411 targeted PVs were successfully disconnected in both groups. Breakthroughs were most frequent at the bottom of superior PVs (85% prevalence) and the top of inferior PVs (75% prevalence). A wide activation front (>5 synchronous bipoles) indicating broad breakthrough was observed in 18% of PVs. Polarity reversal occurred with 88% sensitivity and 91% specificity at breakthrough sites. Polarity reversal was restricted to fewer bipoles (2.0 +/- 0.4 bipoles vs. 3.4 +/- 2.0 bipoles, p < 0.01) compared with earliest activation. Shorter RF application time was required to disconnect PVs with wide synchronous activation using polarity reversal compared with using conventional earliest activity (10.3 +/- 3.0 min vs. 12.3 +/- 3.4 min, p < 0.05). CONCLUSIONS: Bipolar electrogram polarity reversal allows more precise localization of breakthrough compared with the earliest activation, particularly in cases of wide synchronous PV activation.     

Use of the LocaLisa mapping system during ablation procedures in patients with atrioventricular nodal reentrant tachycardia

INTRODUCTION: LocaLisa is a novel system for anatomical mapping. It enables an assessment of the three-dimensional position of electrodes within cardiac chambers without fluoroscopy. With this technique it may be possible to reduce radiation exposure during catheter-based ablation procedures. AIM: To evaluate the efficacy and safety of ablation procedures performed using the LocaLisa mapping system in patients with atrioventricular nodal reentrant tachycardia (AVNRT). METHODOLOGY: This study evaluated the course of the first 26 ablations performed using the LocaLisa system (studied group). The control group involved 30 consecutive patients with AVNRT treated with the conventional ablation technique that was routinely used prior to the introduction of the novel system into clinical practice. RESULTS: In the studied group procedural duration was 72.4+/-24.9 minutes, in the control group 80.1+/-18.2 minutes (NS). However, radiation exposure was significantly lower in the examined group -- 74.4+/-109.2 mGy compared to 184.8+/-59.9 mGy in the control group (p <0.05). All procedures were successful. No complications related to the ablation were observed. CONCLUSIONS: Employment of the LocaLisa mapping system enables the reduction of fluoroscopic exposure without any decrease of efficacy or elevation of risk of any complications during AVNRT ablations.     

Electrophysiological pulmonary vein antrum isolation with a multielectrode basket catheter is feasible and effective for curing paroxysmal atrial fibrillation: efficacy of minimally extensive pulmonary vein isolation.

BACKGROUND: How extensive should an appropriate pulmonary vein (PV) ablation be is a matter of controversy. OBJECTIVE: The study's aim was to investigate the efficacy of minimally extensive PV ablation for isolating the PV antrum (PVA) with the guidance of electrophysiological parameters. METHODS: Fifty-five consecutive symptomatic paroxysmal atrial fibrillation (PAF) patients underwent PV mapping with a multielectrode basket catheter (MBC). A 31-mm MBC was deployed in 3-4 PVs as proximally as possible without dislodgement, and the longitudinal PV mapping enabled us to recognize single sharp potentials formed by the total fusion of the PV and left atrial potentials around the PV ostium or the transverse activation patterns that were observed. Those potentials were defined as PVA potentials. Radiofrequency ablation was performed circumferentially targeting PVA potentials with the end point being their elimination. RESULTS: After circumferential PVA ablation, electrical disconnection was achieved in 77% and residual PVA conduction gaps were observed in 23% of all targeted PVs. Those residual conduction gaps were mainly located at the border between ipsilateral PVs (42%) and between the left PVs and left atrial appendage (33%) and were eliminated by a mean of 3 +/- 2 minutes of local radiofrequency deliveries. During the follow-up period (11 +/- 5 months), 46 (84%) patients were free of symptomatic PAF without any anti-arrhythmic drugs. No PV stenosis or spontaneous left atrial flutter occurred. CONCLUSIONS: Electrophysiological PVA ablation with an MBC is feasible and effective for curing PAF because this minimally extensive PVA isolation technique targets the optimal sites, achieving both high efficacy and safety.     

Pulmonary vein isolation and left atrial catheter ablation using a three-dimensional navigation system for the treatment of atrial fibrillation

BACKGROUND:

Atrial fibrillation (AF) is often triggered by ectopic foci originating from pulmonary veins (PVs), with the posterior left atrium (LA) comprising part of the substrate for maintenance. Catheter ablation strategies targeting PVs and the posterior LA may be further refined by incorporating technology beyond standard fluoroscopy.

OBJECTIVES:

To prospectively assess the usefulness of a navigation system to guide a radiofrequency catheter ablation strategy, combining PV isolation (PVI) with anatomical LA ablation.

METHODS:

Sixty-four patients (51 men; mean [± SD] age 52±8 years) who were referred for catheter ablation of paroxysmal (n=49) or persistent (n=15) AF underwent this ablation strategy using the NavX system (Endocardial Solutions Inc, USA). Electrical PVI was guided by a circular mapping catheter. Anatomical ablation consisted of lines drawn along the posterior aspect of the LA from the superior PVs to the inferior PVs. NavX was used for the construction of three-dimensional LA and PV maps with projection of mapping and ablation catheters on the image in real time and for tracking of lesions during posterior LA ablation.

RESULTS:

Electrical PVI was achieved in 100% of procedures and all patients underwent the linear posterior LA ablation described above. Procedural and fluoroscopy times were 188±41 min and 60±12 min, respectively. Repeat procedures for AF recurrence were required in 38 (59%) patients. After a mean follow-up period of 16±10 months, 59 (92%) patients remained arrhythmia-free, including 52 (81%) without antiarrhythmic drugs.

CONCLUSIONS:

An AF ablation strategy that combines nonfluoroscopic visualization of catheters with electrical PVI and anatomical LA ablation is feasible, safe and effective, but often requires repeat procedures.     

The LocaLisa system as the key to shortening the procedure duration and fluoroscopy time during ablation of atrial fibrillation

BACKGROUND: Ablation of atrial fibrillation (AF) can be difficult and time-consuming. Systems facilitating catheter navigation may be helpful. AIM: To compare the efficacy of the LocaLisa system with the conventional mapping/ablation approach to radiofrequency (RF) ablation of AF. METHODS: Group 1, consisting of 64 patients (48 male; aged 51.5+/-10.6 years), underwent segmental isolation of the pulmonary veins with the Lasso catheter and the LocaLisa system. Group 2, consisting of 64 patients (44 male, aged 51.4+/-11.0 years), had RF ablation guided by means of a conventional fluoroscopy-based approach. Clinical and procedural data were analysed. RESULTS: Nine patients from group 1 and three patients from group 2 had persistent AF. In group 1 the mean number of isolated veins was 3.98+/-0.96, while in group 2 - 4.0+/-0.95 (NS). In group 1 cavotricuspid isthmus lines were created in four patients and lines in the roof of the left atrium in two patients. One patient needed slow pathway ablation. In group 2 six patients had ablation of the cavotricuspid isthmus and a line was created at the roof of the left atrium in one patient. Two patients had ectopic activity ablated in the crista terminalis. Procedure times were 131.6+/-40.3 and 170.0+/-56.5 min (p <0.0001) and fluoroscopy times were 16.93+/-9.7 and 35.66+/-12.7 min (p <0.0001) for groups 1 and 2, respectively. Long-term efficacy of RF ablation was similar in both groups (for example, complete success was achieved in 59% of patients using LocaLisa and 50% without using this system, NS). CONCLUSIONS: The LocaLisa navigation system makes it possible to shorten both the duration of the procedure and the total fluoroscopy time during ablation of AF.