29例房束型和短房室型Mahaim纤维的电生理特点与射频消融结果

目的报道29例房束型和短房室型Mahaim纤维的电生理特点与射频消融结果。方法对29例Mahaim纤维患者（房束型10例,短房室型19例）进行心内电生理检查和射频导管消融治疗。结果29例患者Mahaim纤维只存在递减性前向传导功能,其中2例合并隐匿性房室旁路（左侧游离壁和右侧中间隔各1例）,2例合并三尖瓣峡部依赖型心房扑动,3例合并房室结双径路（均为慢快型）。经Mahaim纤维前传的逆向性房室折返性心动过速时,房束型心室最早激动点在右心室心尖部,短房室型心室最早激动点在三尖瓣环消融靶点处。于三尖瓣环的心房侧成功消融所有Mahaim纤维,其中28例于三尖瓣环游离壁的心房侧消融成功,1例于右心房中间隔消融成功。13例标测到明显的Mahaim纤维电位,25例（房束型9例,短房室型16例）有效消融时出现加速性Mahaim纤维的自主心律。合并房室结双径路、隐匿性房室旁路和三尖瓣峡部依赖型心房扑动者,分别给予以慢径改良、旁路消融和右心房峡部线性消融。随访（17＋8）个月,无1例心动过速复发。结论Mahaim纤维多位于三尖瓣环游离壁。导管消融是Mahaim纤维介导的心动过速安全、有效的治疗方法。消融中出现加速性Mahaim纤维自主心律可以作为判定有效消融的预测指标。消融术前和术后应进行详尽的电生理检查以明确是否合并其他的心动过速。     

心房颤动时显性房室旁道的射频消融治疗

对 2 6例预激综合征患者于心房颤动 (简称房颤 )时射频消融显性房室旁道。其中左侧旁道 9例、右侧旁道17例 ,2 2例有阵发性房颤史。房颤发作伴旁道前传时的心室率为 171± 32 ( 132～ 2 37)bpm。采用经主动脉逆行法或穿间隔法消融左侧旁道、经股静脉途径消融右侧旁道 ,以最早心室前向激动点且有小A波处为消融靶点。房颤时成功消融靶点的V波较体表心电图预激波的起点提前 37.2± 8.1( 2 6～ 5 3)ms。放电 6± 3( 1～ 16 )次后 ,2 6例中有2 5例 ( 96 % )旁道前传被阻断 ,1例失败。阻断旁道前传后 30min ,3例自行恢复窦性心律 ,2 2例经直流电复律后恢复窦性心律 ,心室起搏示 2 5例中有 2 3例旁道逆传已被阻断 ,2例仍存在 ,经继续消融获得成功。随访 19.2± 11.7( 1～ 38)个月 ,除 1例复发正向前传型房室折返性心动过速 (O AVRT) ,经再次消融旁道逆传成功外 ,其他患者无O AVRT发作及旁道前传恢复的证据。结论 :心房颤动时射频消融显性房室旁道方法可行、成功率高     

前传递减性旁路的标测和消融

目的　总结Mahaim’s纤维参与折返的心动过速的电生理特点和射频消融结果。方法　对 7例患者 ,其中男 5例 ,女性 2例 ,平均年龄 2 6 7岁± 7岁 (18～ 35岁 )的左束支传导阻滞型心动过速患者进行了射频消融。在心动过速、窦性心律或心房起搏情况下 ,消融导管沿三尖瓣环心房面标测 ,标测到有明显Mahaim’s束电位处作为消融靶点。结果　 7例患者全部消融成功 ,旁路只有递减性前向传导功能 ,7例患者均属于Mahaim’s纤维分型中的房束纤维。靶点位置全部在三尖瓣环的心房侧 ,均能标测到明显的Mahaim’s束电位。术后平均随访 (2 1± 8)个月 ,1例复发后再次消融成功。结论　本文 7例患者均属于Mahaim’s纤维分型中的房束纤维 ,成功消融靶点均能记录到明显的Mahaim’s束电位。我们的体会是消融此类纤维最好能记录到Mahaim’s束电位 ,消融心房的插入点 ,此方法成功率高、并发症少且明显减少X光暴露时间     

Mahaim纤维及其参与心律失常治疗研究现状

Mahaim纤维是电生理特性有别于大多数普通房室旁道的一组旁道,现有的外科、心内电生理检查、导管消融资料已经证实,目前Mahaim纤维参与的心动过速主要是由起源于右房游离壁的具有缓慢、递减、单向前传功能的特殊纤维,即右房-分支纤维或右房-室纤维所致,表现为宽QRS波的逆向型房室折返性心动过速,为完全预激的室上性心动过速,可经导管射频消融根治,以在三尖瓣环上记录到Mahaim电位作为首选标测方法。     

逆向型房室折返性心动过速的临床特点

探讨逆向型房室折返性心动过速 (ADRT)的临床特点。 397例预激综合征患者进行常规电生理检查和导管射频消融术 ,2 2 (5 .5 % )例 (包括Mahaim纤维旁道 12例 )诱发出ADRT ,心动过速的周长为 30 2± 5 6 (2 30～ 4 10 )ms,2例心动过速时出现低血压伴有头晕 ,4例在心动过速时演化为心房颤动。通过与患者既往临床心电图比较 ,证实 17例有ADRT临床发作 ,常见于多旁道和年轻的患者 (15 / 2 2例 ) ,12例同时伴有顺向型房室折返性心动过速。 19例多旁道患者中 15例逆传经旁道 ,4例逆传经旁道和 /或房室结。 3例单旁道患者在静脉点滴异丙肾上腺素后诱发ADRT ,逆传经房室结。参与构成ADRT的 4 1条旁道 19条位于右侧游离壁 ,9条位于右后间隔 ,3条位于左后间隔 ,7条位于左侧游离壁。 12例前传经Mahaim纤维的ADRT ,其逆传旁道均位于后间隔。 7例普通旁道参与的心动过速其前传支和逆传分别位于右侧、左侧游离壁。 3例单旁道均位于右侧游离壁。结论 :ADRT最常见于多旁道患者并有多种形成机制。     

心房起搏法在房室结射频消融术中的应用

目的探讨对房室结折返性心动过速,射频消融术中应用心房起搏的效果。方法6l例房室结折返性心动过速被随机分为心房起搏组(n=30)、常规组(n=31)进行射频消融术,比较两组消融放电次数、时间、能量及并发症、复发率等。结果与常规组比较,心房起搏组缩短总放电时间(132.6±48.2svs178.4±58.4sP<0.05),增加单次持续放电的成功率(93.3%vs6.5%,P<0.001),同时可减少术中并发症和降低术后复发率,常规组有3例术中出现一过性房室阻滞,1例永久性房室阻滞,3例术后1年内复发,而起搏组无一例出现上述现象。结论房室结射频消融术中采用心房起搏法进行放电比常规法更为安全有效。     

Mahaim样纤维的电生理特点和射频消融治疗

目的　总结前传递减性右心房 -右心室旁路的电生理特点和射频消融结果。　方法　对 7例患者 ,其中男性 3例 ,女性 4例 ,平均年龄 (32± 16 )岁左束支阻滞图形的逆向型房室折返性心动过速患者进行电生理检查和射频消融治疗。　结果　 7例患者的旁路只有递减性前向传导功能 ,三磷酸腺苷能够阻断旁路的传导。心动过速时 ,行心房期前刺激和标测心室最早激动点 ,证实旁路起止于邻近三尖瓣环的右心房和右心室。于三尖瓣环上成功消融所有的旁路 ,消融部位的局部 V波明显提前 [平均 V-δ间期(2 5± 4) ms],但不伴有旁路电位。平均随访 (16± 5 )个月 ,无 1例心动过速复发。　结论　前传递减性右心房 -右心室旁路是“Mahaim样纤维”的一种类型 ,射频消融术为有效的治疗方法 ,成功消融部位可不伴有旁路电位。     

预激综合征合并完全性房室阻滞的诊断及治疗

目的 报道5例预激综合征合并完全性房室阻滞患者的诊断和治疗。方法 进行心内电生理检查和射频消融旁路。结果 电生理检查未诱发房室折返性心动过速，心房刺激时体表心电图的预激程度无变化。消融阻断旁路前传后，均示完全性房室阻滞。4例患者在消融术后植入永久性起搏器．随访中无心房颤动发作。1例患者放弃对旁路的消融治疗。结论 预激综合征合并完全性房室阻滞是射频消融的适应证。消融前对房室传导功能的评定十分重要。成功消融旁路后应植入永久性起搏器。     

房室结慢径消融后对快径前传不应期影响

<正> 房室结双径路(DAVNP)是形成房室结折返性心动过速的必须电生理基础,射频消融房室结慢径路是治疗房室结折返性心动过速(AVNRT)安全、有效的方法.射频消融慢径路后有学者发现快径路前传不应期发生改变,本文对慢径路消融后快径路前传不应期改变,探讨慢径路消融后对快径路前传不应期的影响.1 资料和方法1.1 病例选择经电生理检查证实为DAVNP伴AVNRT患者44例,其中男性21例,女性23例;年龄15～77岁,平均年龄46.77±14.89岁;病史0.6～30年,均有反复发作室上性心动过速史.无器质性心脏病证据.合并房室结快径经消融者未选入.     

射频消融慢径治疗未能诱发的房室结折返性心动过速

电刺激不能诱发出临床发作的阵发性室上性心动过速可能延误心律失常的正确诊断,并且不利于判断射频消融的终点。房室结折返性心动过速患者可能出现上述情况。国内马长生报道房室结折返性心动过速未能诱发率为6.6%。应用射频消融慢径治疗房室结双径路并自发而未诱发的阵发性室上性心动过速,目前意见尚不一致,且长期疗效并不明确。本研究的目的是评价导管射频消融慢径对自发而未诱发的房室结双径路并发房室结折返性心动过速的临床疗效。　　资料和方法　23例患者均有阵发性室上性心动过速发作病史,平均病程(5±2)年,平均年龄(48±12)岁,其中男…     

房束旁道的电生理特点与Mahaim电位在射频导管消融中的意义

探讨房束旁道的电生理特点与Mahaim电位在射频导管消融 (RFCA)中的意义。 1997年 7月至 2 0 0 3年 1月对 3例拟诊为房束旁道引起的逆向型房室折返性心动过速的患者进行了电生理检查和RFCA。男 2例 ,女 1例 ,年龄分别为 18,2 3,2 5岁。心动过速发作史 7～ 16年 ,频率 180～ 2 30次 /分 ,发作时均有明显心悸 ,其中 1例伴头晕、胸闷。窦性心律时心电图 1例正常 ,另 2例示轻微预激。食管心房调搏与心房程序刺激均易诱发心动过速 ,心动过速时体表心电图呈宽QRS波形。 3例均在三尖瓣环右后侧壁标测到的Mahaim电位处 ,于窦性心律及心房起搏下放电消融。 2例彻底阻断旁道前向传导 ,另 1例反复放电未阻断旁道 ,但重复术前程序刺激心动过速不再诱发。分别随访 5年、2年、6个月心动过速均未复发。结论 :RFCA治疗房束旁道介导的心动过速安全有效 ,Mahaim电位在RFCA中具有重要指导价值。     

下位法射频消融慢径路改良房室结治疗室上性心动过速23例

用下位法射频消融慢径路改良房室结治疗房室结折返性心动过速(AVNRT)18例,房室折返性心动过速(AVRT)5例.AVNRT中16例为慢—快型,1例快—慢型,1例慢—快型与快—慢型并存,18例慢径路全部阻断成功.AVRT中1例显性预激,4例隐性预激,有5例慢径路和3例房室旁路消融成功.射频放电时21例出现结性心律.无严重并发症出现.AVNRT病人中随仿1—15个月有1例复发,第二次射频成功.认为下位法射频消融阻断慢径路成功率高,并发症少.     

Multiple anterograde atrioventricular node pathways in patients with atrioventricular node reentrant tachycardia

Objectives. This study sought to investigate electrophysiologic characteristics and possible anatomic sites of multiple anterograde slow atrioventricular (AV) node pathways and to compare these findings with those in dual anterograde AV node pathways.Background. Although multiple anterograde AV node pathways have been demonstrated by the presence of multiple discontinuities in the AV node conduction curve, the role of these pathways in the initiation and maintenance of AV node reentrant tachycardia (AVNRT) is still unclear, and possible anatomic sites of these pathways have not been reported.Methods. This study included 500 consecutive patients with AVNRT who underwent electrophysiologic study and radiofrequency ablation. Twenty-six patients (5.2%) with triple or more anterograde AV node pathways were designated as Group I (16 female, 10 male, mean age 48 ± 14 years), and the other 474 patients (including 451 with and 23 without dual anterograde AV node pathways) were designated as Group II (257 female, 217 male; mean age 52 ± 16 years).Results. Of the 21 patients with triple anterograde AV node pathways, AVNRT was initiated through the first slow pathway only in 3, through the second slow pathway only in 8 and through the two slow pathways in 9. Of the five patients with quadruple anterograde AV node pathways, AVNRT was initiated through all three anterograde slow pathways in three and through the two slower pathways (the second and third slow pathways) in two. After radiofrequency catheter ablation, no patient had inducible AVNRT. Eleven patients (42.3%) in Group I had multiple anterograde slow pathways eliminated simulataneously at a single ablation site. Eight patients (30.7%) had these slow pathways eliminated at different ablation sites; the slow pathways with a longer conduction time were ablated more posteriorly in the Koch's triangle than those with a shorter conduction time. The remaining seven patients (27%) had a residual slow pathway after delivery of radiofrequency energy at a single or different ablation sites. The patients in Group I had a longer tachycardia cycle length, poorer retrograde conduction properties and a higher incidence of multiple types of AVNRT than those in Group II.Conclusions. Multiple anterograde AV node pathways are not rare in patients with AVNRT. However, not all of the anterograde slow pathways were involved in the initiation and maintenance of tachycardia. Radiofrequency catheter ablation was safe and effective in eliminating critical slow pathways to cure AVNRT.     

Radiofrequency catheter ablation of Mahaim tachycardia by targeting Mahaim potentials at the tricuspid annulus.

BACKGROUND--Reentrant tachycardias associated with Mahaim pathways are rare but potentially troublesome. Various electrophysiological substrates have been postulated and catheter ablation at several sites has been described. OBJECTIVE--To assess the efficacy and feasibility of targeting discrete Mahaim potentials recorded on the tricuspid annulus for the delivery of radiofrequency energy in the treatment of Mahaim tachycardia. PATIENTS--21 patients out of a consecutive series of 579 patients referred to one of three tertiary centres for catheter ablation of accessory pathways causing tachycardia. All had symptoms and presented with tachycardia of left bundle branch block configuration or had this induced at electrophysiological study. In all cases, the tachycardia was antidromic with anterograde conduction over a Mahaim pathway. RESULTS--6 patients had additional tachycardia substrates (4 had accessory atrioventricular connections and 2 had dual atrioventricular nodal pathways and atrioventricular nodal reentry). After ablation of the additional pathways, Mahaim potentials were identified in 16 (76%) associated with early activation of the distal right bundle branch and radiofrequency energy at this site on the tricuspid annulus abolished Mahaim conduction in all 16 cases. In 2 patients there was early ventricular activation at the annulus without a Mahaim potential but radiofrequency energy abolished pre-excitation. In the remaining patients no potential could be found (1 patient), no tachycardia could be induced after ablation of an additional pathway (1 patient), or no Mahaim conduction was evident during the study (1 patient). During follow up (1-29 months (median 9 months)) all but 1 patient remained symptom free without medication. CONCLUSIONS--Additional accessory pathways seem to be common in patients with Mahaim tachycardias. The identification of Mahaim potentials at the tricuspid annulus confirms that most of these pathways are in the right free wall and permits their successful ablation and the abolition of associated tachycardia.     

PR/RR Interval Ratio During Rapid Atrial Pacing:

Method for Confirming Slow Pathway Conduction. Introduction: Although the AV conduction curve in patients with AV nodal reentrant tachycardia (AVNRT) is usually discontinuous, many patients with this arrhythmia do not demonstrate criteria for dual AV nodal pathways. During rapid atrial pacing, the PR interval often exceeds the pacing cycle length when there is anterograde conduction over the slow pathway and AVNRT is induced. The purpose of this prospective study was to determine the diagnostic value of the ratio of the PR interval to the RR interval during rapid atrial pacing as an indicator of anterograde slow pathway conduction in patients undergoing electrophysioiogic testing. Methods and Results: The PR and RR intervals were measured during rapid atrial pacing at the maximum rate with consistent 1:1 AV conduction in four study groups: (1) patients with inducible AV nodal reentry and the classical criterion for dual AV nodal pathways during atrial extrastimulus testing (AVNRT Group 1); (2) patients with inducible AV nodal reentry without dual AV nodal pathways (AVNRT Group 2); (3) control subjects ≤ 60 years of age without inducible AV nodal reentry; and (4) control subjects > 60 years of age without inducible AV nodal reentry. For both groups of patients with inducible AV nodal reentry, AV conduction was assessed before and after radiofrequency ablation of the slow AV nodal pathway. Before slow pathway ablation, the PR/RR ratio exceeded 1.0 in 12 of 13 AVNRT Group 1 patients (mean 1.27 ± 0.21) and 16 of 17 AVNRT Group 2 patients (mean 1.18 ± 0.15, P = NS Group 1 vs Group 2). After slow pathway ablation, the maximum PR/RR ratio was < 1.0 in all AVNRT patients (Group 1 = 0.59 ± 0.08, P < 0. 00001 vs before ablation: Group 2 = 0.67 ± 0.11; P < 0.00001 vs before ablation). Among both groups of control subjects, the PR/RR ratio was > 1.0 in only 3 of 27 patients with no relation to patient age. Conclusion: The ratio of the PR interval to the RR interval during rapid atrial pacing at the maximum rate with consistent 1:1 AV conduction provides a simple and clinically useful method for determining the presence of slow AV nodal pathway conduction. This finding may be particularly useful in patients with inducible AV nodal reentry without dual AV nodal physiology on atrial extrastimulus testing.     

Shortening of conduction time over arborized atrioventricular accessory pathway with Mahaim fibers physiology just before interruption during radiofrequency ablation

A 21-year-old woman had paroxysmal wide QRS tachycardia with a left bundle branch block configuration and a retrograde conducted P wave just behind the QRS complex. An electrophysiological study revealed antidromic atrioventricular tachycardia involving an atrioventricular connection with decremental conduction as the anterograde limb and normal atrioventricular node as the retrograde limb. During constant pacing from the high right atrium (HRA) at the cycle length (CL) of 600 ms, the QRS configurations were not identical to those during the wide QRS tachycardia or constant pacing at the CL of less than 500 ms. The process by which this arborized atrioventricular accessory pathway with the Mahaim fibers physiology was interrupted by radiofrequency catheter ablation is described. Radiofrequency energy was delivered to the site recording a Mahaim potential at the tricuspid annulus during constant pacing from the HRA at the CL of 429 ms. The stimulus-QRS interval gradually shortened as it reached the power plateau without changing the preexcited QRS configuration. Shortening of the conduction time over the Mahiam pathway might have resulted in changing of the propagation from a slow to fast conduction zone or acceleration in response to thermal effect in a node-like structure on the atrial insertion site.     

Electrophysiologic characteristics,electropharmacologic responses and radiofrequency ablation in patients with decremental accessory pathway

Objectives. This study sought to characterize the functional properties of decremental accessory atrioventricular (AV) pathways and to investigate their pharmacologic responses.Background. Although decremental AV pathways associated with incessant reciprocating tachycardia have been studied extensively, information about the electrophysiologic characteristics and pharmacologic responses of anterograde and retrograde decremental AV pathways is limited.Methods. Of 759 consecutive patients with accessory pathway-mediated tachyarrhythmia, 74 with decremental AV pathways were investigated (mean age 43 ± 18 years). After baseline electrophysiologic study, the serial drugs adenosine, verapamil and procainamide were tested during atrial and ventricular pacing. Finally, radiofrequency catheter ablation was performed.Results. Five patients had anterograde decremental conduction over the accessory pathway but had no retrograde conduction. Of the 64 patients with retrograde decremental conduction over the accessory pathway, anterograde conduction over the pathway was absent in 41 (64%), intermittent in 5 (8%) and nondecremental in 18 (28%). In the remaining five patients, anterograde and retrograde decremental conduction over the same pathway was found. The anterograde and retrograde conduction properties and extent of decrement did not differ between anterograde and retrograde decremental pathways. Posteroseptal pathways had the highest incidences of anterograde and retrograde decremental conduction. Intravenous adenosine, procainamide and verapamil caused conduction delay or block, or both, in 10 of 10, 10 of 10 and 4 of 10 of the anterograde and 20 of 20, 20 of 20 and 8 of 20 of the retrograde decremental pathways, respectively. All patients had successful ablation of the decremental pathways without complications. During the follow-up period of 31 ± 19 months, only one patient experienced recurrence.Conclusions. Decremental accessory pathways usually had functionally distinct conduction characteristics in the anterograde and retrograde directions. Their pharmacologic responses suggested the heterogeneous mechanisms of decremental conduction.     

显性旁道在心房颤动时的标测与消融

目的　探讨心房颤动 (Af)时对显性旁道 (AP)的标测与消融方法。方法　 7例 AP患者 ,年龄 2 4～ 6 0岁。均有阵发性 Af史。Af发作伴旁道前传时的心室率为 12 0～ 2 0 0 bpm。采用经主动脉逆行法消融左侧旁道 ,经股静脉途径消融右侧旁道 ,以心室前向激动点最早、且有小 A波为靶点。结果　 7例患者标测到了较体表心电图预激波起点提前 2 5～ 5 0 ms的 V波 ,首次消融以 15 W能量放电 ,均在 1s～ 8s内旁道前传阻断。3例在旁道前传阻断的同时转为窦性心律 ;1例 30 min内自行转为窦性心律 ;3例经药物转为窦性心律。行心室起搏 ,6例旁道逆传已阻断 ,1例经消融后逆传阻断。随访 5～ 45个月 ,无旁道前传恢复的证据 ,亦无室上性心动过速发作。结论　在掌握适应证的前提下 ,Af时行射频消融阻断显性旁道是可行的。