左心房及肺静脉同步食管CT血管成像在心房颤动射频消融术中的辅助作用

目的:心房-食管瘘是心房颤动介入及心脏外科手术射频消融治疗中少见但严重的并发症,伴有极高的病死率。最安全有效的预防心房-食管瘘发生的方法,应当是术前了解左心房、肺静脉及周围脏器解剖关系,预防消融烧伤食管心房段。我们进行了术前64层螺旋CT(64层MSCT)左心房及肺静脉成像同时引入食管造影检测食管和左心房的毗邻关系。方法:232例左心房及肺静脉成像(心房颤动组146例,对照组86例),同步进行食管联合造影,即注射造影剂的同时食管吞入造影剂,以观察食管走形和左心房的关系。根据食管心房后壁段与上下PV的关系将食管走形分为:I、II型,其中各型又分别分为abc三种亚型。融合影像的同时,在CARTO系统上显示LA-PV及ESO的三维重建关系,以指导完成肺静脉隔离。结果:228例患者中,I型-Ia39例(心房颤动组24例、对照组15例),占17.11%,Ib55例(心房颤动组39例、对照组16例),占24.12%,Ic 76例(心房颤动组48例、对照组28例),占33.33%;II型-IIa27例(心房颤动组16例、对照组11例),占11.84%,IIb18例(心房颤动组10例、对照组8例),占7.89%,IIc13例(心房颤动组7例、对照组6例),占5.70%。食管跨左心房后壁段长度平均为(55.04±9.01)mm[心房颤动组(54.77±9.49)mm、对照组(55.51±8.14)mm],食道厚度约为(2.26±0.64)mm[心房颤动组(2.25±0.63)mm、对照组(2.30±0.65)mm],左心房后壁厚度中位数房颤组0.6mm(0.3mm,2.9mm)、对照组1.4mm(0.3mm,2.9mm)。食道前壁距左心房最小距离中位数房颤组1.75mm(0mm,5mm)、对照组2.15mm(0mm,4.4mm)。所有心房颤动组患者均完成了肺静脉隔离。结论:本中心完成一组大样本量国人食道左心房肺静脉CT成像,提出6种分型,但心房颤动组和对照组数据在长度、厚度、距离和分型上无明显差异。利用融合影像学技术在射频消融术中指导解剖位置,提高手术安全性。     

最紊乱的心房颤动波在心房内分布特点及肺静脉隔离对其影响

目的针对心房颤动(房颤)基质消融是房颤消融的最终目标,最紊乱的房颤波(Ⅲ型房颤)所在部位可能为房颤维持的关键所在。本文分析Ⅲ型房颤波在双侧心房的分布特点及肺静脉隔离对其影响。方法11例持续性房颤患者,用普通的电生理检查导管或64极Basket导管分别在上腔静脉、右心房游离壁、右心房后壁、右心耳、右心房间隔部、左心房后壁、左心耳、肺静脉及冠状静脉窦记录2分钟房颤心内电图。根据Wells对房颤电活动的分类,人工计算Ⅲ型房颤占所记录的2分钟心电图的百分比(房颤紊乱指数,DI)。比较肺静脉隔离前及房颤自动终止或电复律前冠状窦口及冠状窦中、远端房颤紊乱指数的变化。肺静脉隔离在房颤中进行。在窦性心律下证实仍然存在心房—肺静脉间电活动传导,在窦性心律或心房刺激下完成肺静脉隔离。结果在所有720次采样中,房颤紊乱指数成双峰分布,第二峰起始点为75%。在左心房后壁(包括肺静脉)采样326次,房颤紊乱指数大于75%占22.4%,在间隔部(包括冠状静脉窦开口部)采样118次,房颤紊乱指数大于75%占37.3%,在心房其它部位(包括右心房游离壁、右心房后壁、上腔静脉、左心耳及冠状静脉窦左房部)采样276次,房颤紊乱指数大于75%占6.2%。左心房后壁及间隔部与心房其它部位比较有统计学差异(P<0.001)。肺静脉隔离导致了冠状静脉窦远端的房颤电活动变化(房颤紊乱指数消融前14.34±25.01,消融后4.62±8.64,P=0.016),而对冠状静脉窦口无明显影响(房颤紊乱指数消融前37.49±38.09,消融后46.83±41.96,P=0.243)。平均随访7个月,6例患者维持窦性心律,5例患者转为阵发性或持续性房颤。结论Ⅲ型房颤多集中在左心房后部,包括肺静脉。肺静脉隔离可降低Ⅲ型房颤在左心房的百分比,而对右心房影响较小。提示Ⅲ型房颤的集中部位可能为房颤维持的关键部位,肺静脉隔离可能改变了房颤维持的物质基础。     

以双向阻滞作为阵发性心房颤动肺静脉电隔离终点的临床研究

目的 评价以左心房-肺静脉电联系双向阻滞作为环肺静脉消融电隔离术终点对阵发性心房颤动(房颤)导管消融疗效的影响.方法 在76例阵发性房颤患者导管消融达到左心房-肺静脉传入阻滞后,分别于每根肺静脉内起搏评价肺静脉-左心房传导情况.据此分为双向阻滞组(传入与传出均阻滞)和传入阻滞组,随访观察房颤导管消融的临床疗效.结果 76例均完成导管消融术,306根肺静脉(2例患者存在右中肺静脉)均达到左心房-肺静脉电学传入阻滞之传统终点.18例消融术后左心房-肺静脉传导呈双向阻滞,58例仅传入阻滞.平均随访(6.85±1.08)个月,1次消融成功率为77.63％.其中,双向阻滞组为83.33％,传入阻滞组为75.86％,两组相比差异无统计学意义(P＞0.05).术后房性心动过速发生率5.26％(4/76),无心脏压塞、脑栓塞、左心房食管瘘等并发症以及死亡发生.结论 以左心房-肺静脉传导双向阻滞为房颤导管消融终点治疗阵发性房颤的策略似乎临床疗效较好.     

消融指数指导心房颤动导管消融的短期疗效及安全性

目的探讨消融指数(AI)指导心房颤动(简称房颤)导管消融的短期疗效及安全性。方法选择2018年6月至2019年5月在苏州大学附属第一医院拟行射频消融术的房颤患者116例为研究对象,其中阵发性房颤患者75例、持续性房颤患者41例。所有患者均在Carto3三维标测系统AI指导下应用压力监测导管行环肺静脉隔离及心房线性消融,相邻消融点间距离6 mm,肺静脉前壁和嵴部AI≥400以及后壁、顶部和下壁AI≥300为消融目标。术后每3个月随访1次,若患者出现症状及时行心电图和24 h动态心电图检查。消融成功标准:3个月空白期后无抗心律失常药物的情况下未发生持续时间30 s的房性心律失常。结果①AI指导下房颤消融时间为(60.8±10.6) min,每消融点阻抗下降为(11.5±6.3)Ω,肺静脉单圈隔离成功率为91%;②随访时间为(9.1±3.2)个月,失访3例,阵发性和持续性房颤患者消融成功率分别为90.4%及87.5%;③在围手术期及随访过程中,仅术中发生1例一过性脑缺血发作,术后心脏超声发现少量心包积液2例,无心包压塞、脑栓塞、肺静脉狭窄和心房食管瘘等严重并发症。结论 AI指导下行房颤导管消融术是安全可行的,可提高房颤消融效率、肺静脉单圈隔离率及短期疗效。     

节段性肺静脉电隔离治疗阵发性心房颤动的方法学

目的 对阵发性心房颤动(房颤)经药物治疗无效并接受射频导管消融治疗的患者，采用经改良的节段性电隔离方法隔离肺静脉进行治疗，并研究该方法的有效性及安全性。方法 61例阵发房颤患者采用一次房间隔穿刺技术，分别送入标测及消融电极导管。应用猪尾造影导管用高压注射器非选择性左心房造影显示肺静脉开口及左心耳位置，指导导管行进方向以减少心脏压塞风险。标测中常规探查、标测右下肺静脉，避免遗漏可能触发房颤的肺静脉电位。在肺静脉与左心房之间肺静脉电位优势传导部位用温控导管或冷盐水灌注导管做多点消融形成节段性隔离。结果 单个节段或多个节段消融可使肺静脉与左心房之间形成完全性电隔离，使肺静脉电位消失。节段性隔离靶肺静脉173根，即刻成功168根，成功率97．1％。术中2例发生心脏压塞，1例左上肺静脉狭窄60％。结论 节段性电隔离肺静脉法可有效隔离肺静脉，可替代点状隔离和环状隔离方法。与其他传统方法比较，手术时间短、成功率高，可明显减少肺静脉的损伤和避免肺静脉狭窄的发生。     

108例心房颤动射频消融治疗后14例并发症分析

目的探讨心房颤动(简称房颤)经导管射频消融治疗的安全性。方法 100例阵发性和8例持续性房颤患者,采用Carto标测构建左房三维电解剖图,行肺静脉造影了解其形态,以环状Lasso电极导管多导联双极记录最早肺静脉电位处(传导方向自左心房至肺静脉)、最早心房电位处(传导方向自肺静脉至左心房)为初步消融靶点,围绕左和右侧肺静脉口线性消融,隔离肺静脉。术中持续抗凝治疗,在房间隔穿刺完成后常规静脉注射普通肝素,以100～140IU/kg弹丸式注射,随后15～18IU.kg-1.h-1静点或弹丸式注射;术前、术后均严格抗凝治疗。结果 108例患者均完成预定的线性消融。术后少量心包积液2例,术后1例出现顽固性呃逆,其他并发症包括严重迷走反射3例,术后房扑3例,一过性ST段抬高1例,血气胸1例,颈部血肿3例,随访(8.5±3.8)月,(6～12)个月,未见其他并发症。结论房颤导管消融治疗总体比较安全。肺静脉造影指导、以低功率(20～30W,50℃),在肺静脉开口部消融对于减少心房穿孔、肺静脉狭窄的发生具有重要作用。手术前常规行经食管超声(TEE)和/或螺旋CT检查排除心房血栓,并在手术前后及术中进行规范抗凝治疗可有效预防手术相关血栓栓塞并发症。     

EnSite NavX指导下无肺静脉造影的阵发性心房颤动导管消融术

目的探讨不作肺静脉造影行阵发性心房颤动(房颤)环肺静脉电隔离术的有效性和可行性。方法 34例阵发性房颤患者分为无肺静脉造影组(n=18)和肺静脉造影组(n=16),无肺静脉造影组不作肺静脉造影,余步骤与肺静脉造影组相同,两组均在EnSiteNavX三维标测系统指导下重建左心房及肺静脉,再分别行左、右环肺静脉电隔离术,消融终点为肺静脉与心房完全电隔离。结果无肺静脉造影组消融术时间[(92.78±19.46)minvs.(106.44±20.18)min,P0.05]及X-线曝光时间[(11.47±4.32)minvs.(16.06±8.72)min,P0.05]少于肺静脉造影组,差异有统计学意义。两组左心房三维重建时间[(6.22±2.65)minvs.(6.31±3.00)min,P0.05]、左、右侧环肺静脉消融时间[(21.61±7.66)minvs.(20.50±8.09)min,P0.05;(17.33±10.22)minvs.(17.48±7.86)min,P0.05]及即刻消融成功率[100%(18/18)vs.100%(16/16),P0.05]比较,差异无统计学意义。结论不作肺静脉造影,仅在三维标测系统指导下行房颤消融治疗,可达到相同消融效果,可节省消融术及X-线曝光时间,减少手术步骤、耗材和费用。     

环肺静脉电隔离术后房性快速心律失常的机制和再消融治疗

目的分析环肺静脉电隔离术后，房性快速心律失常（ATa）发生机制和再次消融治疗结果。方法采用Lasso导管和电解剖（Carto）标测，对135例房颤患者行环同侧肺静脉电隔离消融术。术后随访时间3个月以上的102例患者中，33例患者仍有ATa发作。其中20例接受再次消融治疗。再次消融术均采用单Lasso导管标测，Carto指导下点状消融肺静脉与心房的传导点（gap），或环肺静脉线性消融左心房。消融成功终点为双侧肺静脉电隔离。结果Lasso导管标测表明，20例患者均存在心房与肺静脉（A—PVP）的电传导，一侧和双侧A—PVP传导分别为8例和12例。再次消融，18例患者达到肺静脉电隔离（其中10例为局部补点式消融，余8例行环肺静脉线性消融）。另2例患者的左侧或双侧肺静脉未能电隔离。平均随访（5．5±5．3）个月，18例术中达到消融终点的患者，仅1例仍有阵发性房颤。结论环肺静脉线性消融术后，存在或恢复左心房与肺静脉的电传导是导致ATa发生的主要原因。再次消融电隔离肺静脉是成功治疗的关键。     

环肺静脉前庭隔离消融术与7字线消融术治疗心房颤动的对比研究

目的：比较环肺静脉前庭隔离消融术与7字线消融术两种不同术式治疗心房颤动（房颤）的有效性和安全性。方法：对我科在EnSite三维指导下行房颤导管消融治疗的136例患者（阵发性房颤组93例,持续性房颤组43例）进行回顾性分析,按照其房颤类型和消融术式分为阵发性房颤环肺静脉前庭隔离消融者（45例）,阵发性房颤7字线消融者（48例）,持续性房颤环肺静脉前庭隔离消融者（18例）,持续性房颤7字线消融者（25例）,比较两术式对患者左心房直径、消融成功率、并发症情况、消融时间和X线曝光时间等因素的影响。结果：通过12个月的随访,两术式在治疗阵发性房颤组和持续性房颤组的成功率和并发症上均无显著统计学差异。对于阵发性房颤组,两术式均能有效减小左心房直径（P<0.01）。在手术时间上,7字线消融者明显短于环肺静脉前庭隔离消融者时间（P<0.01）,但两术式X线曝光时间未见明显差异。结论：在房颤治疗中,环肺静脉前庭隔离消融者与7字线消融者均具有较高的有效性与较好的安全性,能有效逆转阵发性房颤中左心房重构。     

心房颤动导管消融术前食管造影对消融策略及预防食管损伤的价值研究

目的 采取术前心脏CT检查评估食管与左心房、肺静脉的解剖关系，优化心房颤动(房颤)导管消融安全策略，最大限度减少食管损伤。方法 选择2019年1月至2021年10月苏北人民医院心血管内科首次行射频导管消融和冷冻球囊消融术的老年房颤患者118例，所有患者成功行术前食管造影和心脏增强CT检查，左侧型102例，非左侧型16例。按照消融方式不同分为射频消融组86例和冷冻消融组32例。随访观察食管损伤相关症状的发生情况。结果 食管前壁距离左上肺静脉、左下肺静脉、右上肺静脉、右下肺静脉分别为(12.20±6.55)mm、(7.13±3.32)mm、(24.10±9.72)mm、(18.10±8.35)mm,其与左下肺静脉距离最近，有统计学差异(P<0.05)。下肺静脉水平食管与左心房后壁接触宽度为(18.12±4.54)mm。左侧型与非左侧型患者食管距离左上肺静脉、左下肺静脉、右上肺静脉、右下肺静脉比较，有统计学差异(P<0.01)。射频消融组左侧型与非左侧型患者食管距离左上肺静脉、左下肺静脉、右上肺静脉、右下肺静脉比较，有统计学差异(P<0.05,P<0.01);冷冻消融...     

Anatomic relationship of the esophagus and left atrium: implication for catheter ablation of atrial fibrillation

STUDY OBJECTIVES: Atrioesophageal fistulas have been reported to be a lethal complication following catheter ablation of atrial fibrillation (AF). The purpose of this study was to investigate the relationship between the esophagus and posterior left atrium (LA) and provide the anatomic information necessary to minimize the risk of esophageal injury during AF ablation. METHODS AND RESULTS: Forty-eight patients (43 men; mean +/- SD age, 59 +/- 12 years) with drug-refractory paroxysmal AF and 32 control subjects (26 men; mean age, 60 +/- 9 years) were included. All underwent a CT scan for delineation of the relationship between the esophagus and posterior LA. In the paroxysmal AF group, two major types of esophageal routes were demonstrated. Type 1 routes were found in 42 patients with the lower portion of esophagus close to the ostium of the left inferior pulmonary vein (LIPV), including three subtypes of courses according to the proximity to the left superior pulmonary vein (PV) and LIPV. Type 2 routes were found in six patients with the lower portion of esophagus close to the ostium of the right inferior pulmonary vein (RIPV), including three subtypes of courses according to the proximity to the right superior PV and RIPVs. The mean shortest distance of the esophagus to the four individual PVs significantly differed between type 1 and type 2: 28.4 +/- 6.1 mm vs 10.5 +/- 5.7 mm (to the right superior), 19.6 +/- 7.0 mm vs 3.7 +/- 3.4 mm (to the right inferior), 10.1 +/- 3.4 mm vs 22.8 +/- 4.2 mm (to the left superior), and 2.8 +/- 2.5 mm vs 18.7 +/- 5.2 mm (to the left inferior), respectively (p < 0.001 for all). Contact of the esophagus and middle part of posterior LA was observed in each patient. However, direct contact of the aorta with the posterior LA wall was more frequent in type 2 than in type 1 (p = 0.001). The clinical characteristics, type of esophageal routes, distance from the esophagus to the four PVs, and diameter of the thoracic cage, LA, and aorta in the control group were similar to those in the AF group (p > 0.05 for all). CONCLUSION: Although the anatomic relationship between the esophagus and LA posterior wall varied widely, two major patterns of esophageal routes could be depicted. This information is important for deciding the location of the ablation lesions around the PV ostia and LA and for avoiding the potential risk of esophageal injury.     

Topographic variability of the esophageal left atrial relation influencing ablation lines in patients with atrial fibrillation

Topography of the esophagus in atrial fibrillation ablation. INTRODUCTION: The close anatomic relationship of the posterior wall of the left atrium (LA) and the thermosensitive esophagus creates a potential hazard in catheter ablation procedures. METHODS AND RESULTS: In 30 patients (pts) with atrial fibrillation (AF) undergoing catheter ablation, we prospectively studied the course and contact of the esophagus in relation to LA and the topographic proximity to ablation lines encircling the right-sided and left-sided pulmonary veins (PV) as well as to the posterior line connecting the encircling lines using the electromagnetic mapping system for reconstruction of LA and for tagging of the esophagus. This new technique of anatomic tagging of the esophagus was validated against the CT scan as a standard imaging procedure. The esophageal course was highly variable, extending from courses in direct vicinity to the left- or right-sided PV as well as in the midportion of the posterior LA. In order to avoid energy application in direct proximity to the esophagus, adjustments of the left and right PV encircling lines were necessary in 14/30 pts (47%) and 3/30 (10%). In 30 pts (100%), the mid- to inferior areas of the posterior LA revealed contact with the esophagus. Therefore, posterior and inferior linear ablation lines were abandoned and shifted to superior in 29 pts (97%). CONCLUSIONS: Anatomic tagging of esophagus revealed a highly variable proximity to different areas of the posterior LA suggesting individual adjustment of encircling and linear ablation lines in AF ablation procedures to avoid the life threatening complication of esophagus perforation.     

Accuracy of intracardiac echocardiography for assessing the esophageal course along the posterior left atrium: a comparison to magnetic resonance imaging

Background: Atrioesophageal fistula is a potentially fatal complication of ablation in the left atrium (LA) to treat atrial fibrillation. Objective: The objective of our study was to systematically evaluate the diagnostic potential of intracardiac echocardiography (ICE) for accurately assessing the esophageal course along the posterior LA. Methods: Thirty‐five patients underwent magnetic resonance imaging (MRI) before and ICE during pulmonary vein (PV) isolation to visualize the esophagus. The location of the esophagus was determined in relation to the PVs and anatomic regions of the LA by both ICE and MRI. Using the MRI images as a reference, the accuracy of ICE localization was assessed. Results: The most common location for the esophagus to appear was the mid‐posterior wall (80% of patients by ICE, 71% of patients by MRI), followed by the left posterior wall (71% of patients by ICE, 63% of patients by MRI) and the right posterior wall (60% of patients by ICE, 51% of patients by MRI). The esophagus was seen to course near the left PV antrums (left superior PV antrum 34% of patients by ICE and MRI; left inferior PV antrum 34% of patients by ICE, 37% of patients by MRI), left superior PV (17% of patients by ICE, 20% of patients by MRI), left inferior PV (17% of patients by ICE and MRI), right inferior PV antrum (29% of patients by ICE, 37% of patients by MRI) and the right inferior PV (3% of patients by ICE, 17% of patients by MRI). The sensitivity for esophageal location by ICE compared to that by MRI ranged between 33% (right inferior PV) and 92% (left superior PV antrum, left inferior PV antrum, and mid‐posterior wall). The specificity for esophageal location by ICE compared to that by MRI ranged between 60% (mid‐posterior wall) and 100% (right inferior PV). The positive predictive value ranged between 80% (left inferior PV) and 100% (right inferior PV). The negative predictive value ranged between 84% (right inferior PV antrum) and 96% (left superior PV antrum). Conclusion: Phased array ICE provides rapid, real‐time localization of the esophagus during LA ablation that is comparable to MRI.     

Lasso环形标测电极导管指导阵发性心房颤动肺静脉电隔离

探讨在Lasso环形标测电极导管指导下对阵发性心房颤动 (PAF)患者行肺静脉电隔离术的安全性、有效性。顽固性PAF患者 30例 ,男 19例 ,年龄 5 3± 15 (41～ 70 )岁 ,在肺静脉口用Lasso环形电极导管对肺静脉逐一进行标测 ,于肺静脉最早的心房 肺静脉电位处消融 ,电学隔离肺静脉。消融温度控制在 5 0℃ ,功率 2 5～ 35W。结果 :电学隔离肺静脉 6 9根 ,其中左上肺静脉 2 8根、左下肺静脉 2 0根、右上肺静脉 15根、右下肺静脉 6根 ,电隔离成功6 5根 ;电隔离上腔静脉 6根 ,左房后游离壁异位兴奋灶消融 8个 ,无手术相关并发症。即刻成功率 94 %。随访10 .1± 5 .1(5～ 2 2 )个月 ,成功率 (无心房颤动发作 ) 6 1%。结论 :在Lasso环形标测电极导管指导下对PAF患者行肺静脉电隔离术安全有效 ,是一种很有前途的治疗PAF的消融方法。     

Complex anatomy surrounding the left atrial posterior wall: analysis with 3D computed tomography

Few studies have explored the topographic anatomy of the esophagus, posterior wall of the left atrium (LA), or fat pads using multidetector computed tomography (MDCT) to prevent the risk of esophageal injury during atrial fibrillation (AF) ablation. MDCT was performed in 110 consecutive patients with paroxysmal or persistent AF before the ablation procedure to understand the anatomic relationship of the esophagus. Two major types of esophagus routes were demonstrated. Leftward (type A) and rightward (type B) routes were found in 90 and 10% of the patients, respectively. A type A route had a larger mean size of the LA than type B. The fat pad was identifiable at the level of the inferior pulmonary vein in 91% of the patients without any predominance of either type. The thickness of the fat pad was thinner in the patients with a dilated LA (>42?mm) than in those with a normal LA size (??42?mm) (p?=?0.01). The results demonstrated that the majority of cases had a leftward route of the esophagus. There was a close association between the LA dilatation and fat pad thinning. With a dilated LA, the esophagus may become easily susceptible to direct thermal injury during AF ablation. Visualization of the anatomic relationship may contribute to the prevention of the potential risk of an esophageal injury.     

Real-Time Rotational ICE Imaging of the Relationship of the Ablation Catheter Tip and the Esophagus During Atrial Fibrillation Ablation

Introduction: Atrioesophageal fistula is a rare complication of atrial fibrillation (AF) ablation that should be avoided. We investigated whether rotational intracardiac echocardiography (ICE) can help to minimize ablation close to the esophagus.
Methods and Results: We studied 41 patients referred for catheter ablation of refractory AF. A rotational ICE catheter was inserted into the (LA) to determine the location of the esophagus. The esophagus was identified to be either adjacent to the pulmonary vein (PV) ostium or to a cuff 2 cm outside the ostium. Circumferential ablation was performed at the PV ostium, with the exact ablation location determined by ICE. The relationship of the catheter tip to the esophagus was imaged during energy delivery, allowing interruption when respiration moved the tip closer to the esophagus. Out of 41 patients, the esophagus was seen near left-sided PVs in 32 and near right-sided PVs in three patients. The median distance from LA endocardium to esophagus was 2.2 mm (range, 1.4–6 mm). In 21 of 35 patients with a closely related esophagus, ablation over the esophagus was avoided by ablating either lateral or medial to the esophagus. In 14 patients, the esophagus could not be avoided, and risk was minimized by limiting lesion size. Significant movement (>10 mm) of the esophagus during the procedure occurred in 3/41 cases.
Conclusion: Rotational ICE can accurately determine the distance of ablation sites from the esophagus. Real-time imaging of the relationship of the ablation catheter tip to the esophagus may reduce the incidence of esophageal injury.     

Mechanisms of recurrent atrial fibrillation: comparisons between segmental ostial versus circumferential pulmonary vein isolation

Background: Electrical isolation of pulmonary veins (PVs) is an effective therapy for atrial fibrillation (AF). Both segmental ostial PV ablation and circumferential ablation with PV–left atrial (LA) block have been implicated to eliminate AF. However, the mechanism of the recurrent AF after undergoing either strategy remains unclear.
Methods and Results: Of the 73 consecutive patients with symptomatic AF that underwent PV isolation and had recurrences of AF, Group 1 consisted of 46 patients (age 56 ± 13 years old, 35 males) who underwent PV isolation by segmental ostial PV ablation and Group 2 consisted of 27 patients (age 51 ± 11 years old, 24 males) who underwent circumferential ablation with PV–LA block. In Group 1, the earliest ectopic beat or ostial PV potentials were targeted. In Group 2, circumferential ablation with PV–LA block was performed by encircling the extraostial regions around the left and right PVs. During the first procedure, all patients had PV–AF. There was no difference in the non-PV ectopy between Group 1 and Group 2. During the second procedure, the incidence of an LA posterior wall ectopy initiating AF was significantly lower (20% vs. 0%, P = 0.01) in Group 2. There was no difference in the PV ectopy initiating AF during the second procedure.
Conclusion: Circumferential ablation of AF with PV–LA block may eliminate the LA posterior wall ectopy and decrease the incidence of LA posterior wall ectopy initiating AF during the second procedure.     

心房颤动患者食管与左心房形态学关系的多层螺旋计算机断层摄影术研究

目的应用多层螺旋计算机断层摄影术（MSCT）探讨心房颤动（房颤）患者食管与左心房形态学的关系。方法房颤射频消融术前行多层螺旋计算机断层摄影术肺静脉成像的患者,共收取左心房图像质量最佳者100例[其中男性60例,女性40例,平均年龄：38—75（55．5±10．0）岁],应用三维重建及多平面技术;测量食管与左心房的位置走形,食管与各肺静脉口的距离,观察食管与左心房间脂肪垫的连续性,食管与左心房紧密接触部（该处无脂肪垫）的位置,测量该接触位置的平均长度及宽度,测量左心房的直径。结果91％的食管位于左心房后壁中线偏左侧,其中的65％平行于左上及左下肺静脉口;26％呈从右上向左下方斜行。食管与各肺静脉口的距离0～50．8mm,其中48％的食管距左上肺静脉口的距离〈5mm。95％的食管与左心房间可见脂肪垫,其中96％呈间断性。食管与左心房紧密接触部位以左下肺静脉处最多见（占75％）。食管与左心房后壁接触的平均长度6．5—66．0（40．2±9．6）mm;平均宽度3．5～23．0（15．1±1．6）mm。食管的平均宽度15．7—24．9（20．2±4．7）mm。左心房的直径：上下径（45±3）mm;前后径（54±4）mm。结论在房颤患者中,食管与左心房及肺静脉间的解剖关系变化很大。大多数患者食管距左肺静脉最近;食管与左心房紧密接触部的位置以左下肺静脉处最多见（占75％）,在房颤射频消融术前行MSCT可以很好地显示食管与左心房间的形态解剖,对于防止食管损伤很重要。     

Comparison of 2 mapping strategies for pulmonary vein isolation.

BACKGROUND: Pulmonary vein (PV) isolation using a circular catheter (CC) creates an entrance block from the left atrium (LA) to PV to eliminate paroxysmal atrial fibrillation (PAF). We describe a new approach for PV isolation during distal PV pacing using a basket catheter (BC). The purpose of the present study was to compare 2 mapping strategies for PV isolation. METHODS AND RESULTS: Of 100 consecutive patients with PAF, 50 underwent CC-guided PV isolation and 50 underwent BC-guided PV isolation. During CC-guided ablation, the endpoint was the elimination of PV potentials based on the entrance block from the LA to PV. During BC-guided ablation during distal PV pacing, the endpoint was the elimination of bidirectional PV-LA conduction. At 12 months, 62% of patients who underwent CC ablation and 80% of patients who underwent BC ablation were free of symptomatic PAF without the use of antiarrhythmic drugs (p<0.05). The incidence of mild (<50%) PV stenosis in BC ablation was significantly lower than that in CC ablation (12 vs 24%, p<0.01). CONCLUSIONS: This new approach for PV isolation during distal PV pacing using BC is useful for confirming a bidirectional PV-LA conduction block and is more effective than CC ablation.