Insights into the mechanism of idiopathic left ventricular tachycardia: a case report and literature review

Left ventricular posterior fascicular tachycardia (LVPFT) is an idiopathic form of VT characterized by right bundle branch block morphology and left axis deviation. The mechanism of LPFVT is thought to be localized reentry close to the posterior fascicle. We present the case of a 24-year-old medical student who was admitted to the emergency department complaining of palpitations. The ECG showed an aspect suggestive of LVPFT. Vagal maneuvers, adenosine and i.v. Metoprolol were ineffective in terminating the arrhythmia. Conversion to sinus rhythm was obtained 10 h later, with i.v Amiodarone. The ECG in sinus rhythm showed left posterior fascicular block. Because antiarrhythmic drugs were not desired by the patient, VT ablation was proposed. The electrophysiological study identified the mechanism of arrhythmia to be reentry using the slowly conducting verapamil-sensitive fibers as the antegrade limb and the posterior fascicle as the retrograde limb. Radiofrequency applications near the posterior fascicle, in the lower half of the interventricular septum, at the junction of the two proximal thirds with the distal third interrupted the tachycardia and made it non-inducible at programmed stimulation. The case is unusual as the patient had a left posterior fascicular block during sinus rhythm before ablation. This demonstrates that the reentry circuit of VT does not need antegrade conduction through the posterior fascicle for perpetuation.     

特发性左后分支室性心动过速2种消融方法的对比分析

目的探讨对特发性左后分支室性心动过速(简称室速)患者进行射频消融时,同时标测到舒张期电位(diastolic potential,DP)和最早收缩期前P电位(Purkinje potential,PP)作为靶点的消融方法,是否优于以最早PP为消融靶点的方法。方法对18例左后分支室速患者进行电生理检查,根据消融靶点不同分为2组:DP组(同时标测到DP和PP)和PP组(仅标测到最早PP)。以室速不再被诱发作为消融成功终点。比较2种方法的成功率、手术时间、X线曝光时间、消融次数、并发症发生率和复发率。结果18例患者中1例不能诱发室速,未行射频消融。17例诱发出临床室速,表现为右束支阻滞形,电轴左偏,其中DP组7例,PP组10例。所有患者均达消融成功终点。DP和PP距体表QRS波的间期分别为(60.17±8.16)ms和(30.64±7.19)ms。2组患者的年龄、室速的周长、手术时间和复发率无统计学差异(P>0.05)。与PP组相比,DP组X线曝光时间较长[(18.33±1.51)minvs(15.37±2.77)min,P=0.03],消融次数较少[(4.55±2.07)次vs(7.50±1.64)次,P=0.0...     

左室特发性心动过速的电生理特点及射频消融治疗

目的:观察左室特发性室速(ILVT)的电生理特点及射频导管消融治疗。方法:通过体表心电图特点初步判断室速起源,激动标测法精确定位室速起源部位,射频消融终点为ILVT不能再诱发。结果:16例ILVT患者,于左后间隔成功消融14例,左前间隔、左室流出道消融成功各1例。结论:体表心电图初步定位ILVT的起源部位,激动标测法精确定位导管消融靶点,此方法简便、直观、准确率高。     

Identification and management of ventricular tachycardia

Recognising ventricular origin of a broad QRS tachycardia helps to appropriately identify and manage patients with ventricular tachycardia (VT) in the emergency. Relatively simple clinical and ECG clues help in reaching the correct diagnosis in the majority of patients. Management strategies vary with the clinical diagnosis and an implantable cardioverter defibrillator (ICD) is indicated for chronic prophylactic therapy in patients with coronary artery disease and serious ventricular arrhythmias, especially in those with ventricular dysfunction. The role of this device in patients with stable VT and ejection fractions > 0.35 deserves closer scrutiny. Radiofrequency ablation mostly plays an adjunctive role. Anti-arrhythmic drugs (amiodarone/sotalol and beta-blockers) are required to prevent frequent recurrences. A hybrid approach combining all these therapeutic modalities is often needed. Prognosis in patients with specific VT syndromes such as right ventricular outflow VT, left ventricular fascicular VT and left ventricular outflow VT is excellent with drugs. Radiofrequency ablation is curative in such syndromes.     

非接触心内膜激动标测系统指导疑难心律失常消融的临床研究

目的 研究非接触心内膜激动标测系统指导疑难心律失常的标测与消融的有效性与优越性。方法 12例患者，男性9例，女性3例，年龄28-76岁，电生理检查为右室特发性室性早搏1例，左室特发性室性心动过速2例，左房房性心动过速1例，右房房性心动过速2例，左房心房颤动6例．其中4例常规电生理标测消融末成功，1例成功后复发．经股静脉置入64极球囊电极和射频消融导管至同一心腔．计算机标测系统首先构建心腔几何构型，然后建立心动过速的腔内等电势图，分析心动过速的起源点及关键峡部，利用计算机导航系统指导消融导管至拟定靶点处进行消融，结果 1例起源于右室流出道偏间隔的室性早搏患者行片状消融获得成功；2例左室特发性室性心动过速标测其心动过速起源于左后中间隔及左后间隔区域行片状消融成功；1例左房房性心动过速标测其心动过速起源于右肺下静脉间隔部并指引消融导管行右肺下静脉至二尖瓣之间线性消融获得成功；2例右房房性心动过速巾1例标测其最早激动点位于下腔静脉口，此处行环状消融获得成功，另1例位于上腔静脉后方穿过界嵴中部线性消融获得成功；6例左房房颤患者1例在窦性心律卜标测其敛房颤房早起源于左右上肺静脉之间，行线性消融成功，另5例在房颤发作下标测其房颤起源折返部位，分别行右上下肺静脉、左上下肺静脉、左右上肺静脉之间、左下肺静脉与二尖瓣峡部之间线件消融成功，12例患者术中、术后均无并发症，随访2—26个月，无1例复发．结论 非接触心内膜激动标测系统指导心律失常的心内膜标测与消融是安全有效的，对复杂、难治性心律失常的电生理机制的阐明和指导消融具有较好的临床应用价值，     

窦性心律下射频导管消融起源于希蒲系统特发性室性心动过速的临床观察

目的:探讨窦性心律下射频导管消融(RFCA)起源于希蒲系统特发性室性心动过速(IVT)的临床结果.方法:23例起源于希蒲系统IVT,按消融方法分为两组:(1)心动过速消融组,为9例患者,以心动过速下最早提前P电位为靶点,在心动过速下进行消融;(2)窦性心律消融组,为14例患者,以心动过速下记录最早P电位且窦律下试放电过程中出现同形或近似室性早搏及短阵室性心动过速为靶点,在窦律下进行消融.术后反复程序刺激不能诱发心动过速为消融终点.观察两种不同消融方法的临床结果.结果:两组在手术成功率、手术时间、X线曝光时间、并发症发生率及复发率方面无明显差别.结论:窦性心律下射频消融起源于希蒲系统IVT安全、有效.     

单极起搏标测法在左后分支室性心动过速射频消融术中的应用

目的探讨单极标测法在特发性左后分支室性心动过速射频消融术中的应用。方法选择80例特发性左后分支室性心动过速的患者,随机分为两组,一组采用激动顺序标测法,另一组在激动顺序标测法的同时加用单极标测法进行标测,比较两组的手术成功率及消融功率、消融温度、放电有效时间、手术时间和平均阻抗。结果加用单极标测法治疗组与激动顺序标测法治疗组相比手术成功率分别是（36/37）97.3%,（41/43）95.3%,两组比较无显著性差异。但加用单极起搏标测法治疗组的实际消融功率、实际消融温度、放电有效时间及手术时间均低于激动顺序标测法治疗组,且两组比较有显著性差异P〈0.05。结论在导管消融治疗左后分支特发性室性心动过速中,加用单极标测法可用较低的消融功率、温度进行治疗,缩短了靶点标测及放电有效时间,从而提高手术效率。     

室上性心动过速的多条径路定位及射频消融

目的：探讨室上性心动过速的多条径路定位及射频消融。　方法：经电生理检查,９例患者均在窦性心律、心房、心室程序刺激及诱发心动过速下标测,观察在冠状窦（ＣＳ）、高右房（ＨＲＡ）、希氏束导联存在不同的心室或心房激动顺序。　结果：９ 例患者共检出１８ 条径路,其中左游离壁８ 条,左后间隔５ 条,右前间隔１ 条,房室结双径路（ＡＶＮＤＰ）４条。在４条双径路中,只有１ 条参与房室结折返性心动过速（ＡＶＮＲＴ）。　结论：成功射频消融多条径路的关键,在于对每一患者进行详细的电生理检查及标测,对患者全部临床资料及窦性心律、心律失常发作时１２导联心电图的综合分析。     

特发性室速的临床特点分析

目的探讨特发性室速的临床特点.方法收集23例特发性室速和21例病因明确的继发性室速病人的资料,分别从临床表现、心电图特点和治疗进行对比分析.结果两组比较,特发性室速病人年龄较轻,病程较长,出现晕厥及血压下降者较少;室速发作时,左室特发性室速心电图主要表现为右束支传导阻滞(RBBB) 电轴左偏,右室特发性室速主要表现为左束支传导阻滞(LBBB) 电轴右偏(或下偏):射频消融对特发性室速治愈率高,并发症少;特发性室速预后好.结论掌握特发性室速的临床特点,有利于此类病人的诊断、治疗和预后判断.     

Refinement of CARTO-guided substrate modification in patients with ventricular tachycardia after myocardial infarction

Background Substrate modification guided by CARTO system has been introduced to facilitate linear ablation of ventricular tachycardia （VT） after myocardial infarction （MI）. However, there is no commonly accepted standard approach available for drawing these ablation lines. Therefore, the aim of the present study was to practically refine this time consuming procedure.
Methods Substrate modification was performed in 23 consecutive patients with frequent VTs after MI using the CARTO system. The initial target site （ITS） for ablation was identified by pace mapping （PM） during sinus rhythm and/or entrainment pacing （EM） during VT. According to the initial target site, two approaches were used. The initial target site in approach one has a similar QRS morphology as VT and an interval from the stimulus to the onset of QRS cmplex （S-QRS） of ≥50 ms during PM in sinus rhythm or a difference of the post pacing interval and VT cycle length ≤30 ms during concealed entrainment pacing of VT; The initial target site in approach two has an similar QRS morphology as VT and an S-QRS of 〈50 ms during PM in sinus rhythm.
Results Overall, 50 lines were performed with a length of （35±11） mm. Procedure time averaged （232±56） minutes, fluoroscopy time （10±8） minutes. Sixteen patients were initially involved into approach one. After completion of 3±1 ablation lines, no further VT was inducible in 13 patients. The remaining 3 patients were switched to use the alternative approach. However, in none of them the alternative approaches were successful. Approach two was initially used in 7 patients. After completion of 3±1 ablation lines, no further VT was inducible in only 2 patients. The remaining 5 patients were switched to approach one, which resulted in noninducibility of VT in 4 of them. The initial successful rate was significantly higher in the group of approach one compared to that in the group of approach two （13/16 patients vs 2/7 patients, P=-0.026）.
Conclusions The approach for     

维拉帕米敏感性室性心动过速的射频消融术治疗

目的 探讨射频消融术治疗维拉帕米敏感性室性心动过速（室速）的有效性和安全性。方法 选择本院18例确诊为维拉帕米敏感性室速的患者为研究对象。入院后行相关检查排除器质性心脏病后接受射频消融术。术中寻找Purkinje电位（P电位）,标测到P电位较体表的QRS波提前≥20 ms为理想消融靶点。在25 ～35 W,60℃左右的设置下行消融。其周围位置在同样的设置下消融。达到消融终点后,行右心室刺激或者异丙肾上腺素静滴后再行右心室刺激检验消融效果。术后给予常规治疗及护理。出院后随访3～6个月。结果 18例患者中,17例起源左后分支,1例起源左前分支,室速,分别在左中后间隔及前间隔消融成功。术中全部达到消融终点,均未再能诱发室速。理想靶点的P电位较体表QRS波提前(24.0±3.5)ms。发现提前越多,消融所需时间越少。术后有2例患者出现穿刺口血肿,无其他并发症出现。随访3～6个月,有2例多次心动过速发作,发作性质及心电图同前。治愈率达88.9％。结论 射频消融手术治疗维拉帕米敏感性室速是安全有效的,可以达到根治的目的,但有一定的复发率。     

心大静脉不同部位室性心律失常的心电图特征及射频导管消融治疗

目的 探讨心大静脉（GCV）不同部位室性期前收缩（PVCs）和室性心动过速（VT）的心电图特征及射频导管消融治疗的疗效与安全性.方法 4例经GCV标测和消融患者,其中持续及短阵性VT各1例,PVCs2例.经左、右心室流出道（LVOT、RVOT）及二尖瓣环心内膜标测与试消融无效各2例,最后均经GCV标测与消融,并对GCV远端（前室间静脉分支前-二尖瓣环前壁心外膜）及最远端（前室间静脉分支后-LVOT）消融成功者的心电图特征进行分析.结果 首次均采用普通温控导管仅1例消融成功,因阻抗太高无法放电失败3例,其中2例再次经三维标测系统EnSite3000-NavX指导下,采用盐水灌注导管标测与消融均成功,1例放弃再次消融,成功率75.00%.经GCV远端及最远端消融成功各1及2例.激动顺序标测有效靶点心内电图较体表心电图QRS波群起始点提早（36.00±2.65）ms,可见A波及V波（V＞A） 起搏标测的QRS波群与自发PVCs/VT形态12及11导联相同各2例.GCV远端及最远端消融成功者体表12导联心电图特征不同：（1）前者假性＂δ＂波时间≥75ms而后者＜75ms （2）前者V1呈R型无S波群而V4～V6有S波（呈Rs型）,后者则相反.结论 部分体表心电图特征符合LVOT或二尖瓣环前壁起源的PVCs/VT,经上述部位标测与消融无效者,应考虑经GCV采用盐水灌注导管进行标测与消融,且安全有效.     

邻近希氏束的快速心律失常的射频消融

目的：探讨邻近希氏束的快速心律失常患者射频消融的策略。方法：对43例邻近希氏束的心动过速患者常规进行电生理检查,明确其机制后采取相应措施进行经导管射频消融术（RFCA）。希氏束旁路的消融在心动过速时进行,而室性心动过速则在窦性心律时消融。记录手术过程、所用器材及并发症发生情况。结果：43例中,10例为希氏束旁路,2例为房性心动过速,30例为房室结折返性心动过速,1例为特发性左心室室性心动过速。首次射频消融成功率为93％(40/43),复发2例,再次消融均成功。30例使用了Swartz R0鞘管。3例房室结双径路患者消融慢径路时出现一过性房室阻滞。结论：邻近希氏束的心动过速射频消融成功率较高,但有一定的特殊性,应采取不同的消融策略,术中尤需避免损伤希氏束。     

Mechanisms of organized atrial tachycardia during catheter ablation of chronic atrial fibrillation by stepwise approach

Background Extensive atrial fibrillation （AF） ablation is associated with an increased success rate of catheter ablation in chronic AF patients and an increased rate of atrial tachycardia （AT） during the procedure. The mechanism of these Ats varies in previous studies. Our study aimed to report the mechanism of organized AT occurring during the stepwise ablation procedure of chronic AF.Methods A prospective cohort of 86 consecutive patients who underwent an ablation procedure for chronic atrial fibrillation （CAF） was investigated. The stepwise procedure was performed in the following order： circumferential pulmonary vein ablation, complex fractionated atrial electrograms ablation, mapping and ablation of AT. The endpoint was noninducibility of AF/AT after sinus rhythm （SR） was restored or the procedure time was beyond 6 hours.Results Sixty-nine （80%） of patients converted to SR via AT. A total of 179 sustained ATs were observed in 69 patients during the procedure. There were 81% （n=145） macroreentrant ATs which included 65 perimitral circuits, 48 peritricuspid tachycardia and 32 roof dependent circuits, 12% （n=21） localized reentrant and 7% （n=13） focal ATs. Thirty （15%） patients experienced significant left atrium （LA） and LA appendage （LAA） conduction delay or dissociation in the procedure or during the follow-up period.Conclusions Most CAF patients converted to SR via ablation of organized AT occurring during the stepwise procedure. The mechanism of most of these ATs was macro-reentry.     

导管射频消融术对房颤患者左心房结构的影响

目的评价导管射频消融术对心房颤动(AF,房颤)患者左心房结构的影响。方法 43例房颤患者接受治疗,其中阵发性房颤32例,持续性房颤11例。8例行肺静脉电隔离术,35例行Carto指导下环肺静脉前庭隔离术,消融终点均为双侧肺静脉完全电隔离。应用超声心动图测定其消融术前1~3 d和术后1、3个月静息时窦性心律下左心房内径,分析消融术前、后左心房结构的变化。结果 43例房颤患者均成功施行环肺静脉左房线性消融术,随访时间(6±2)月,最短3个月,最长14个月,治愈率93.02%。左房内径消融术后1个月较术前无明显改变[(35.74±5.77)mm vs(35.69±6.25)mm,P>0.05],随访3个月时左房内径较术前显著减小[(31.99±3.66)mm vs(35.69±6.25)mm,P<0.01]。结论房颤患者于术后3个月时左房结构可逆重构。     

射频消融治疗特发性室性心动过速9例临床报告

目的观察射频消融技术治疗特发性室性心动过速 (IVT)的临床效果。方法根据发作IVT时的体表 12导联心电图定位起源部位 ,行心内电生理检查 ,寻找稳定诱发IVT的条件 ,采用激动标测或 (和 )起搏标测相结合的方法标测靶点 ,对起源左心室间隔部的IVT寻找Purkinie电位 (p电位 ) ,标测靶点后放电消融。结果 11例呈RBBB图形伴电轴左偏或重度右偏 ,靶点在左心室间隔面中、下部 ,10例找到p电位。 7例为LBBB图形伴电轴不偏或右偏 ,靶点在右心室流出道 ;1例为LBBB图形伴电轴左偏 ,靶点在右心室流人道。l例IVT同时起源右室流出道的间隔部和游离壁 ,l例左心室特发性室性心动过速 (ILVT)合并房室结折返性心动过速的患者先消融房室结双径路 ,再行ILVT的消融。 1例右心室特发性室性心动过速 (IRVT)消融虽未立即成功 ,因延迟作用 3周后心动过速消失。消融成功患者的临床症状消失 ,未出现手术相关的并发症 ,随访期内所有病例存活。结论射频消融治疗IVT临床疗效肯定、成功率高、安全 ,应作为首选的根治方法。     

特发性室性心动过速的射频消融治疗

目的：报道５ 例特发性室性心动过速射频消融疗效。　方法：５例患者中,右室流出道特发性室速４ 例,左室特发性室速１ 例,均给予射频消融术治疗。　结果：３例右室特发性室速和１例左室特发性室速消融成功,１ 例右室特发性室速好转。４ 例成功患者随访４～２８ 个月无复发,１ 例好转患者消融后仍有室性早搏,但无室性心动过速发生。　结论：特发性室性心动过速消融成功率高,在体表心电图和影像解剖定位指导下,激动标测与起搏标测的结合是寻找消融靶点的有效方法。     

The automaticity of Mahaim fibre and its response to effective ablation

Background Typical accessory pathways (APs) of Wolf-Parkinson-White syndrome have been widely discussed in recent decades. However, the characteristics of the special AP, Mahaim fibre,are not so clear. It is known that these fibres have antegrade conduction only, long conduction time,decremental node-like conduction and automaticity properties. This study was to elucidate the automaticity of Mahaim fibre and its response to effective ablation.Methods Thirteen patients with Mahaim fibre (ten atrioventricular and three atriofascicular accessory pathways) were subjected to electrophysiological study and radiofrequency ablation via catheter. The incidence and characteristics of anautomatic rhythm originating from Mahaim fibre were observed during the whole procedure, especially during radiofrequency current delivery.Results Repetitive and short-run automatic rhythm (rate: 65 -72 beats per minute), with a QRS morphology similar to that of clinical pre-excited atrioventricular re-entrant tachycardia (AVRT),occurred in two patients during sinus rhythm. Conduction via Mahaim fibre was successfully eliminated by radiofrequency current. Fourteen applications of RF were associated with irregularly accelerated automatic tachycardia of Mahaim fibre ( with a sensitivity of 78% ), lasting for 1.2 - 14 seconds.However, such automatic tachycardia of Mahaim fibre did not occur during 54 failed applications of radiofrequency current.Conclusions Mahaim fibre has the function of automaticity. The accelerated automatic tachycardia of Mahaim fibre occur red during radiofrequency catheter ablation can be used as a predictor for successful procedure.