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备注1：内容来源为Sunny Po教授编写的经典著作《Warren Jackman's Art of War: A Sniper's Approach to Catheter Ablation》。

备注2：本章为书籍的第5章，翻译由电生理爱好者申晨和picassoma两位合力完成，欢迎指正补充。

《Chapter 5: Ablation of Accessory Pathways》

《第5章： 旁道的消融》

5.0 RFA篇章概述

Over half of the patients referred to Dr. Jackman’s practice for accessory pathway (AP) ablation had failed prior ablation. Many others without prior ablation had APs in areas that are known to be challenging to ablate or the ablation carries a high risk of AVN injury. Dr. Jackman summarized the causes of AP ablation failure as follows.

根据Jackman医生经验，有超过半数的患者有旁道消融失败的经历(备注：Jackman实验室的很多病人是其他电生理中心消融失败后转诊过去的)。其他许多未行消融术的患者，其旁道所在位置往往是充满挑战的或者消融容易损伤房室结。Jackman医生将旁道消融失败的原因总结如下。

(1)Localization error (60-70% cases). This is mainly caused by failure to appreciate that most APs traverse the AV annulus with an oblique angle. In other words, the angle between the course of an AP and the plane of the AVvalve is not 90degrees(Figure5.1A).

定位错误（60-70%的病例）。这主要是由于未能认识到大多数旁路是以斜行的方式穿过AV环所造成的。换句话说，旁道与AV瓣平面之间的夹角并不是90度（图5.1a)

(2)Wrong diagnosis(5-10%cases). For example, atrio-fascicular AVRT(Mahaim) maybe misdiagnosed as AVNRT with aberrant conduction.

诊断错误（5-10%的病例）。如房束旁道（Mahaim）可误诊为AVNRT伴差异性传导。

(3)Difficult to ablate or high risk of AVN injury(10-15%cases). Anteroseptal or mid-septal AP ablation carries a high risk of AV block; stable electrode-tissue contact can be difficult to maintain for a right freewall AP.

消融困难或房室结损伤风险高（10-15%病例）。前间隔或中间隔区旁道消融具有房室传导阻滞的高风险；对于右游离壁旁道来说，电极-组织难以维持稳定贴靠。

(4)Unusual location (5% cases). APs located in the coronary cusp or left anterior septum below the coronary cusp can be difficult to map and ablate.

位置异常（5%）。位于冠状动脉窦或冠状动脉窦以下的左前隔的旁道可能难以标测和消融。

Figure 5.1. Oblique course of accessory pathway (AP) traversing the AV annulus.

A. An AP takes a perpendicular (blue line) vs. an oblique (red line) course to traverse the AV annulus.

B. The mapping catheter (MAP) recorded a continuous electrogram(VA fusion, in red box), viewed as a good ablation target by many electrophysiologists.

Ventricular activation along the CS was from CSp to CSd(blue arrow). Note that during antegrade AP conduction (3beat), the mapping catheter recorded AV fusion as well (in green box).

C. When AVRT was induced a few seconds later, atrial activation at the same site was late.

Note that the wavefront of ventricular activation (blue arrows) changed during AVRT, leading to a longer VA interval recorded on the mapping catheter. The successful ablation site was 2 cm away from here. Vertical red line: earliest atrial activation.

D.In another patient,the mapping catheter recorded a sharp AP- (red arrow) which disappeared (empty red arrow)when antegrade AP conduction blocked. A sharp AP-P was recorded during retrograde AP conduction as well (3 beat). Note that at the site where an AP-P was recorded, the atrial timing was significantly later than the timing of earliest atrial activation (vertical blue line), indicating that this AP traversed the annulus in an oblique course.

图5.1. 旁路 (AP) 斜行穿过房室环。

A.AP采取垂直 （蓝线）与斜行（红线）的方式穿过AV环。

B.标测导管(MAP)记录连续电图（VA融合，红框），被许多电生理学家视为较好的消融靶点。心室激动沿着CS从CSP（近端）到CSD（远端）（蓝色箭头）。注意，在沿旁道前传期间（3跳），标测导管也记录了房室融合（绿色框内）。

C.几秒钟后AVRT诱发，同一部位的心房激动变晚。注意，心室激动顺序（蓝色箭头）在AVRT发作期间出现改变，导致标测导管上记录的VA间期变长。成功的消融部位距此2厘米。垂直红线：最早心房激动。

D.在另一例患者中，当旁道前传阻滞的时候标测导管记录到尖锐的AP-P（空心红色箭头）消失。在旁道逆行传导过程中也记录到一个尖锐的AP-P（3跳）。注意，在记录AP-P的部位，心房电位时间明显晚于最早心房激动的时间（垂直蓝线），表明该旁路以斜行的方式穿过房室环。

CausesofAccessory PathwayAblationFailure 旁路消融失败原因分析》

5.1 Localization Error 定位错误：

One of the most important discoveries that Dr.Jackman made in AP ablation is that most APs traverse the AV annulus with an oblique angle. Conventional wisdom states that APs traverse the AV annulus in a direction perpendicular to the plane of the AV valve. A number of inferences come from this “wisdom”. First,it would be exceedingly difficult to record an AP potential (AP-P) as it will be buried within the local atrial and ventricular electrograms (EGMs). Second, the best ablation target should be the site where the atrial and ventricular EGM fuse.

Third,the AV or VA interval adjacent to the AP should be fixed regardless of the pacing site. Unfortunately, none of the three inferences hold true. Dr. Jackman also found that approximately two thirds of the failed AP ablation resulted from failure to appreciate the oblique course of APs. As soon as the oblique course is revealed by differential pacing, ablation becomes much easier. Figure 5.1B shows a possible ablation target with a continuous EGM (VA fusion). This site would be a good target if the AP were to traverse the mitral annuls perpendicular to the plane of the AV valve. When AVRT was induced a few seconds later,it was evident that atrial activation there was not early as shown in Fig.5.1C and no AP-P was recorded at that site,either.Ablation was successful at a site 2cm away where a sharp AP-P was recorded.

大多数旁道是以斜行的方式穿过房室环，是Jackman博士在房室旁道消融过程中最重要的发现之一。传统的观点认为房室旁道以垂直于房室瓣环平面的方式穿过房室瓣环。许多结论都来自这一观点。首先，记录旁路电位（AP-P）非常困难，因为旁路电位将埋藏在局部心房和心室电图（EGMs）中。第二，最佳消融靶点应是房室电位融合的部位。

第三，无论起搏部位如何，邻近旁道的AV或VA间期均应固定。不幸的是，这三个结论都不成立。Jackman博士还发现，大约三分之二的旁道消融失败是由于未能认识到旁道斜行穿越房室瓣环。不同位置的起搏一旦揭示旁道是斜行的，消融就变得容易许多。图5.1B显示了具有连续电描记图（VA融合）的可疑消融靶点。如果旁道是垂直角度穿过二尖瓣环，那么这个部位将是一个很好的靶点。几秒钟后当AVRT在被诱发时，很明显心房激动并不像图所示的那样早 （图5.1C）,也未见旁路电位。消融成功的位置在2cm以外有尖锐的旁路电位的地方。

The conclusion that most APs traverse the annulus with an oblique angle is supported by the following observations. The local AV interval during atrial pacing or the local VA interval during ventricular pacing at a site adjacent to the AP indeed changes significantly when pacing is delivered to the septal vs. lateral side of the AP (Fig.5.2). This viewpoint is also supported by a very common observation that the VA interval during RV pacing is substantially different from that during AVRT (Fig. 5.1B-C).

Regardless of how the ventricle is activated, the ventricular activation wavefront has to engage the ventricular end of the AP first before propagating to the atrium.Changes in the VA interval adjacent to the AP can easily be demonstrated by differential ventricular pacing.

Figure 5.2A-B illustrates how a short VA interval is produced if the ventricular wavefront propagates orthodromically to the ventricular end of the AP. In this scenario, the ventricular wavefront propagation is aligned with the orientation of the AP. The ventricular wavefront and AP conduction propagate in the same direction, masking the AP-P as well as the site of earliest atrial activation. When the wavefront is reversed (Figure 5.2C-F), the ventricular wavefront has to bypass the entire length of the AP before it engages the ventricular end of the AP.

When the AP conduction propagates toward the atrium, it isnolongermaskedbythelocalventricularactivationtherebyunmaskingtheAP-Pandthesiteofearliest atrial activation.

大多数旁道以斜行的方式穿过房室环的结论得到了以下结果的支持。当在旁道内侧或者外侧不同部位起搏时，心房起搏时的局部AV间期或心室起搏时的局部VA间期在邻近旁道的部位确实发生了显著变化（图5.2）。这一观点也被一个非常常见的现象所支持，即同一位点在RV起搏的VA间期与AVRT发作期间的VA间期有明显差异（图5.1B-C)。

不管心室是如何激动的，心室激动波阵面在传播到心房之前，必须首先激动旁道心室端。心室不同部位起搏可以导致在邻近旁道的位置出现VA间期的变化。图5.2A-B说明了心室波沿顺斜行旁道方向传导时是如何产生短的VA间期的。在此时，心室波前传方向与旁道分布方向平行。心室波传导方向和旁道分布方向一致时，AP-P与心房最早激动点在同一个位置。当心室波延逆旁道方向激动心房时（图5.2C-F)，心室波传导必须绕过整个旁道，然后传导至旁道的心室插入端。当激动通过旁道传导向心房时，心房波不再被局部心室波所掩盖，从而暴露了AP-P和最早心房激活的部位。

Dr. Jackman defines an AP as taking an oblique course if the AV interval over antegrade AP conduction or the VA interval over retrograde AP conduction changes more than 15 ms by changing the wavefront entering the AP. Importantly, measuring the local AV or VA interval has to be performed at a site in close proximity to the AP. Obviously, the more oblique that an AP traverses the annulus (more deviation from the angle perpendicular to the AV annulus), the more change in the AV or VA interval one would observe.

Figure 5.3A provides a detailed explanation of this important observation. Dr. Jackman’s first choice of ablation target is always the site recording a sharp AP-P. In the best-case scenario, an isolated AP-P is spanned by brief iso-electrical intervals, which suggest that the target is the middle segment of the AP. In this way, mild catheter movement septally or laterally during ablation will not miss the ablation target. The site of earliest atrial or ventricular activation is Dr. Jackman’s 2nd choice when an AP-P is nowhere to be found.

Jackman博士认为在旁道内外侧不同起搏，导致激动旁道方向改变而出现顺向传导时AV间期或逆行传导时VA间期差异超过15毫秒，则该旁路为斜行旁路。更重要的是，此时测量局部AV或VA间期必须在靠近旁道的位置。显然，旁道穿越房室环越斜时（旁道与房室环连线角度越小），AV或VA间期的变化越大。

图5.3A提供了这一重要结果的详细说明。Jackman博士的首选消融靶点是能记录尖锐的AP-P的位置。在最佳情况下，孤立的旁道电位被短暂的等电位线（平台）所跨越，这表明靶点位于旁道的中间段。这样，消融时轻微的将导管向间隔或游离壁侧移动就不会错过消融靶点。当没有找到AP-P时，心房或心室最早激动的部位是Jackman博士消融旁道的第二选择。

图5.2. A-B. 心室波激动方向与旁道逆行方向一致，旁道电位被局部心室激动所掩盖。C-F. 如果波振方向反过来，心室激动需要经过整个旁道的长度才能激动旁路心室插入端。当旁路向心房传导，旁道电位不再被局部心室激动所掩盖。

D Figure 5.3B illustrates the problem of targeting the site of earliest atrial activation. To accurately identify the site of earliest atrial activation, the operator needs to choose the pacing site wisely(Figure5.1and5.2). Even though the ablation catheter is positioned in close proximity to the site of earliest activation, there is still a good likelihood that the catheter may deviate away from the true site of earliest activation,leading to transient AP conduction block due to edema and recurrence of AP conduction later (blue hatched area in Figure 5.3B).

For the vast majority of the left free wallAPs, the ventricular end is more septal(of inferior) than the atrial end (Figure5.3C). The right free wall APs follow a similar pattern but with more exceptions.Note that for the vast majority of the anteroseptalAP, the ventricular end is more lateral than the atrial end.Targeting the ventricular end is a safer approach (see Chapter6formoredetails).

Dr. Jackman usually does not target the sitewith AV or VA fusion because sites showing AV or VA fusion are often distant from the AP location.In the left panel of Figure 5.3A, sites beyond the atrial end of the AP will show VA fusion because the local ventricular activation is so late that it fuses with the local atrial activation; thus, creating a false impression that VA fusion is caused by very early atrial activation.If operators select the pacing site carefully to maximize the VA interval, a sitewith VA fusion is unlikely to be caused by alate local ventricular activation, but by an early local atrial activation.Ablation at this site is more likely to be successful.

图5.3B阐述了最早心房激动部位作为靶点的问题。为了准确识别最早心房激动的部位，术者需要明智地选择起搏部位（图5.1和5.2）。即使消融导管位于最早激动的位置附近，导管仍有很大可能偏离最早激动的真正位置，导致消融过程中组织水肿造成的短暂旁道阻滞，而水肿消退后旁道传导再次恢复（图5.3B中蓝色阴影区）。

对于绝大多数左侧游离壁旁道，心室插入端比心房插入端更偏间隔（下）（图5.3C)。右侧游离壁旁道也具有相似特点，但也有许多例外。对于绝大多数前间隔旁道来说，心室插入端比心房插入端更偏外。因而选择消融心室插入端更安全（更多细节见第6章）。

Jackman教授通常不选择AV或VA融合的部位作为消融靶点，因为AV或VA融合的部位通常远离旁道插入点。在图5.3A的左图中，远离旁道心房插入端以外的部位出现VA融合，因为局部心室激动太晚，以至于与局部心房激动融合；因此，造成了一种错误的印象，即VA融合是由非常早的心房激动引起的。如果术者仔细选择起搏部位以最大化显示VA间期，那么VA融合的部位不太可能是由局部心室激动太晚所导致，而是由局部心房激动提前所导致。在这个部位消融更有可能成功。

Beforedeliveringdifferential pacing to determinethe direction of the oblique course, Dr. Jackman prefers to quickly map the area of interest to figure out the vicinity of the site of earliestventricularactivatingduringatrialpacing orsiteofearliestatrial activationduringventricularpacing.This step is of great importance because meaningless results may be acquired if the most dramatic AV or VA interval change during differential pacing occurs at a site distant from the AP (Figure 5.3D).

This is a major problem for a right freewall AP if no catheter is positioned along the tricuspid annulus. If the operator uses the change of the AV or VA interval in the CS to determine the oblique course of a right free wall AP, the results are essentially useless. For this very reason, the oblique course of a right freewall AP is often overlooked for the absence of a catheter positioned along the tricuspid annulus, contributing to ablation failure of right free wall AP ablation.For a right freewall AP, Dr.Jackman either position a HALO catheter along the tricuspid annuls or position a mapping catheter in the vicinity of the AP before delivering differential pacing.

在进行不同部位起搏以确定斜行旁道方向之前，杰克曼博士更喜欢快速标测兴趣区域，以明确心房起搏时最早心室插入点或心室起搏时最早心房插入点。这一步骤非常重要，因为如果导管远离旁道部位，那么在多部位起搏期间将导致AV或VA间期巨大变化发生而获得毫无意义的结果（图5.3D)。三尖瓣环没有放置导管是消融右侧游离壁旁道的一个主要问题。如果操作者利用CS电极中AV或VA间期的变化来确定右侧游离壁AP的斜行程度，其结果基本上是毫无意义。由于这个原因，右侧游离壁旁道的斜行程度经常被忽略。导致右侧游离壁旁道消融失败。对于右游离壁旁道, Jackman教授要么沿着三尖瓣环放置Halo导管，要么在旁道插入点附近放置标测导管，然后进行差异起搏。

Figure5.3.A.IllustrationofhowchangesinventricularwavefrontpropagationcanchangetheVAintervalsandrevealtheAP potential (courtesy of Dr.Jackman).The ventricular and atrial insertion of this AP is located at CS4 and CS2, respectively.Left panel. Ventricular wavefront propagates from CSp to CSd, entering the AP at CS4. Because the AP and ventricular wavefront propagate in the same direction, the AP potential in the center portion of the AP(CS3)is obscured by ventricular activation.

Then, the ventricular and atrial wavefront continue to propagate in the same direction, leading to a short VA interval at CS2.CSd, which already passes the atrial insertion of the AP at CS2 and shows VA fusion as well.Ablation there would note liminate the AP. Right panel. When the pacing site is changed, ventricular wavefront propagates from CSd to CSp, bypassing CS3(the center portion of the AP) before entering the ventricular end of the AP at CS4. After the ventricular activation enters the AP at CS4, it propagates to CS3 at the time when the ventricular activation of CS3 is long gone, creating a long VA interval andexposing the AP potential.

B.Even though the ablation catheter is positioned in close proximity to the site of earliest atrial activation, there is still a high likelihood that the catheter may deviate away from the true site of earliest activation, leading to ablation failure(bluehatched area).Therefore,Dr.Jackman prefers to target the center portion of the AP where an AP potential is recorded. C. The direction of the oblique course of APs around the mitral and tricuspid annulus is illustrated here.

D. In a patient with an anteroseptal AP, the AV interval recorded by the HB catheter was significantly longer during RAA pacing than that during CS pacing, indicating that the atrial end of this anteroseptal AP was more septal than the ventricular end. The AVinterval recorded by the CS catheter also showed significant changes during differential pacing but these changes are meaningless because the AP is not a left free wall AP. Modified with permission from: Otomo K et al. Circulation. 2001 Jul31;104(5):550-6.

图5.3.A.说明心室波传导方向改变如何改变VA间期并揭示旁道电位（杰克曼博士提供）。此旁道的心室和心房插入点分别位于CS4和CS2。左图.心室波从CSp传导到CSd，在CS4进入旁道。由于斜行旁道方向与心室波前传方向一致，在心室起搏时可以在CS3中段观察到旁道电位。然后，心室和心房波继续向同一方向传播，导致CS2处VA间期较短。在CS2处虽然已经远离旁道的心房插入点，但是显示VA融合。在此处消融不会消除旁道。右图.当起搏部位改变时，心室波传导方向从CSd传播到CSp，在进入旁道的心室插入端前（CS4）绕过CS3（旁道的中心部分）。心室激动在CS4进入旁道后，沿旁道传导的电活动能够在CS3的心室电位较远的地方观察到心房电位，产生较长的VA间期从而暴露旁道。

B.即使消融导管位于最早心房激动部位附近，导管仍有很大可能偏离真正的最早激动部位，导致消融失败（蓝色阴影区）。因此，杰克曼博士更倾向于将能够记录到旁道电位的旁道的中心部位作为消融靶点。C.二尖瓣和三尖瓣环周围旁道的斜行方向如图所示。

D.在前间隔旁道患者中，HB导管记录的房室间期在RAA起搏时明显长于CS起搏时，表明该前间隔旁道的心房插入端比心室插入端更靠间隔。差异起搏时CS导管记录的房室间期也有明显变化，但这些变化没有意义，因为旁道不是位于左侧游离壁。

经许可修改：Otomo K et al. Circulation. 2001 Jul31;104(5):550-6.

Dr.JackmanpreferstomapbothantegradeandretrogradeAPconductiontoselectthebestablation site. Clearly, this approach gathers more information in deciding how to ablate an AP effectively and safely.To map a manifest AP, Dr. Jackman prefers to start with differential atrial pacing and ventricular pacing to determine if the AP takes an oblique course across the annulus as well as the ventricular and atrial end of the AP (Figure 5.4).

To map antegrade AP conduction, differential pacing from the RA and CS is performed first. If it appears to be a left freewall AP,differentialCSpacingfromsitesseptalandlateraltothepresumed APlocationcanhelpdeterminehowtheAPisslanted (Figure5.5A).If the atrial end is more lateral than the ventricular end, pacing from proximal CS will produce longer AV separation to facilitate mapping and ablation.

杰克曼博士更喜欢绘制顺行和逆行旁道传导图，以选择最佳消融位点。显然，这种方法能够为如何有效和安全地消融旁道提供更多的信息。为了绘制一个明显的旁道图，杰克曼博士倾向于从不同部位的心房起搏和心室起搏开始，以确定旁道是否以斜行方式穿过房室环以及明确心室和心房的旁道插入端（图5.4）。

为了绘制顺行旁道传导图，首先从右房和CS进行差异起搏。如果是左侧游离壁旁道，从间隔侧和游离壁侧差异起搏CS电极，能够帮助明确旁道的斜行方向（图5.5a)。如果心房插入端比心室插入端靠游离壁侧，从起搏CS电极近端能够产生较长的房室间隔，以便于标测和消融。

图5.4. 左室游离壁斜行旁道示意图，由心室(A)和心房(B) 差异起搏所揭示。绿色箭头：激动传导方向。注意，起搏波方向反转可以暴露旁道电位以及最早的心室和心房激活部位。蓝色箭头：模糊的旁道电位；红箭头：孤立的电位由波阵面反转暴露出来。经许可修改：Otomo K et al. Circulation. 2001 Jul 31;104(5):550-6.

Figure 5.5. Differential pacing of a left free wall AP. A. In a patient with a left free wall AP, differential pacing was delivered to the proximal (CSp) and distal (CSd) CS. Pacing from CSd led to AV fusion (red box). Reversal of the atrial wave front by proximal CSpacing increased the AV interval (blue box), indicating that the atrial end of this AP is more lateral than the ventricular end. B. The ventricular pacing catheter was positioned at the RV outflow tract (left panel) and basal posteroseptal RV (right panel). Curved red arrows indicate the direction of the ventricular wave front. Green stars: pacing site.

C. Differential pacing from posteroseptal RV (leftpanel) and RVOT (right panel). Note that posteroseptal RV pacing led to ventricular activation from CSp to CSd. RVOT pacingreversed the direction of ventricular activation thereby lengthening the VA interval and unmasking the AP potential (arrows). D. In apatientwithaleftfreewallAP,reversaloftheventricularwavefrontbyanteroseptalRVpacinglengthenedtheVAinterval,indicating hat the ventricular end of the AP was more septal (or inferior) than the atrial end. Modified with permission from: Otomo K et al.Circulation.2001 Jul 31;104(5):550-6.

图5.5. 左游离壁AP的差异起搏。A.在一例左侧游离壁旁道患者中，从CS电极近端（CSP）和远端（CSD）进行差异起搏。从CSD起搏导致房室融合（红框）。从CS近端起搏使心房传导逆转增加房室间期（蓝框），表明此旁道的心房插入端比心室插入端更偏游离壁。B.将心室起搏导管放置于右室流出道（左）和右室后间隔基底部（右）。弯曲的红色箭头表示心室波传导方向。绿星：起搏位点。

C.右室后间隔（左图）和右室流出道（右图）差异起搏。注意后间隔右室起搏导致心室激动从CSP到CSD。右室流出道起搏逆转了心室激动的方向，并且延长了VA间期，暴露了旁道电位（箭头）。D.在左侧游离壁旁道患者中， 经右室前间隔起搏逆转心室激动方向使VA90-9-----间期延长，证实心室插入端比心房插入端更靠间隔（或低位间隔）。经许可修改：Otomo K et al. Circulation. 2001 Jul 31;104(5):550-6.

InmostoftheleftfreewallAPs,theventricularendoftheAPismoreseptal(orinferior)than the atrial end; pacing the ventricle lateral to the atrial end provides the best VA separation. For a left free wall APslocated between the 1 and 3 o’clock position along the mitral annulus, RVOT pacing usually provides the longest VA separation to unmask the AP-P or the site of earliest atrial activation (Figure 5.5B-C).

Operator scan position the pacing catheter in the left pulmonary artery and slowly pull back the catheter during pacing until it stably captures the RVOT. Basal anteroseptal (parahisian site) pacing is the 2nd choice (Figure 5.5D)for mapping left anterior and left anterolateral APs. Dr. Jackman’s practice is to start with differential pacingfirst.IfitisaconcealedleftfreewallAP,hewouldpacefromtheRVOT(orbasalanteroseptalRV)andbasalposteroseptalRVtoselectthepacingsitethatprovides thebestVAseparationformapping/ablation.If it is a manifest AP, he would pace the proximal and distal CS as well (Figure 5.5A).

For a right free wall AP,differential pacing from the basal anterolateral (or anteroseptal) RV and basal posteroseptal RV is generally sufficient for the operator to determine the direction of the oblique course (Figure 5.6). For a manifest rightfreewallAP,differentialpacingfromtheRAAandproximalCShelpstheoperatorgaininsightintothedirectionofthe oblique course.

在大多数左侧游离壁旁道中，旁道的心室插入端比心房插入端更靠间隔（或低位间隔）；在心房插入端靠游离壁侧起搏心室提供了最佳的VA间期。对于位于二尖瓣环1-3点钟位置的左侧游离壁旁道，右室流出道起搏通常提供最长的VA间期，便于暴露旁道电位和最早的心房激动位置（图5.5B-C)。

术者可将起搏导管放置在左肺动脉内，起搏时缓慢回撤导管，直至稳定夺获右室流出道。前间隔基底部(HIS旁)起搏是标测左前和左前外侧旁道的次选起搏方式（图5.5D)。杰克曼教授的经验是先从差异起搏开始。如果是隐匿的左侧游离壁旁道，他将从右室流出道（或右室前间隔基底部）和右室后间隔基底部起搏，为标测/消融提供最佳VA分离的起搏部位。如果是显性旁道，他会对近端和远端起搏CS电极（图5.5A)。

对于右侧游离壁旁道，从右室前侧壁基底部（或前间隔）和后间隔基底部进行差异起搏通常足以确定斜向旁道的方向（图5.6）。对于显性右侧游离壁旁道，从右心耳和CS近端进行差异起搏有助于术者了解斜向旁道的方向。

Figure 5.6. Differential pacing for a right free wall AP. A. Typical pacing sites for a right free wall AP. Atrial pacing: RA appendage vs.CS ostium. Ventricular pacing: basal antero-lateral RV vs.basal posteroseptal RV.B.SchematicrepresentationofVAinterval change by reversal of the ventricular wavefront in an AP whose ventricular end is more inferior and septal to the atrial end.

C. Schematic representation of VA interval change by reversal of paced wavefront in an AP whose ventricular end is more superior and lateral to the atrial end. D.Are presentative example of AV interval change caused by reversing the atrial wavefront by pacing anterolateral(left panel) vs. posteroseptalRA(right panel). Note that the AV interval at the site of earliest ventricular activation(HALO-5)was significantly increased by pacing from the antero-lateral tricuspid annulus.This observation indicates that the atrial end is more inferior and septal to the ventricular end.

图5.6. 右侧游离壁旁道的差异起搏。A.右侧游离壁旁道典型起搏部位。心房起搏：右心耳与CS窦口的比较。心室起搏：右室前外侧基地部与右室后间隔基底部的比较。B.示意图展示通过改变心室波传导方向造成VA间期变化，证实该旁道患者心室插入端较心房插入端更靠低位间隔。

C. 示意图展示通过改变心室波传导方向造成VA间期变化，证实该旁道患者心室插入端较心房插入端更靠高位游离壁。D.右房前外侧（左）与后间隔（右）起搏，除极方向改变引起房室间期改变的典型例子。注意，从三尖瓣环前外侧起搏，最早心室激活部位(HALO-5)的房室间期显著增加。这一观察结果表明，心房插入端较心室插入端更偏低位间隔。

Differentialpacingisparticularlyhelpfulinmapping septalAPs.Forthevastmajorityoftheanteroseptal (or parahisian) APs, the ventricular end is more lateral than the atrial end (Figure 5.7A). This characteristic has important clinical implications (see Chapter6 for details)astheAVnodeisontheatrial side of the tricuspid annulus.

Targeting the ventricular end of the AP is a preferred approach, which is a few millimeters lateral to the AV node an disalsoon the ventricular side of the annulus. Ablationoftheventricularend of the AP may cause RBBB but not AV block. Ablation failure of posteroseptal APs is often caused by diagnostic errors (see Chapter 4) or VA fusion along the course of the AP during RV apex pacing. In this scenario, VA fusion prevents the operator to identify the AP-P or the site of earliest atrial activation (see Chapter 6 for more details). Dr. Jackman’s favorite pacing site to map a concealed posteroseptal or left posterior AP is the lateral coronary vein, the same vein favored by operators implanting CRT leads (Figure5.7B).

Pacing from the lateral coronary vein lengthens the VA interval, unmasking the AP-P and the site of earliest atrial activation. If CS is too small to accommodate a pacing catheter and a mapping catheter, the pacing catheter can be positioned at the basal lateral LV using the retrograde trans-aortic approach.

差异起搏对标测间隔旁道特别有帮助。对于绝大多数前间隔（或希氏束旁）旁道，心室插入端比心房端更靠侧壁（图5.7a)。这一特点具有重要的临床意义（详见第6章），因为房室结位于三尖瓣环的心房侧。

旁道的心室插入端是首选消融靶点，它比房室结更偏外和在三尖瓣环心室侧。消融旁道的心室插入端可能导致完全性右束支传导阻滞，但不会导致房室传导阻滞。后间隔旁道的消融失败通常是由于诊断错误（见第4章）或RV心尖部起搏时沿旁道方向的VA融合造成的。在这种情况下，VA融合阻止操作者识别旁道电位或最早心房激活的部位（更多细节见第6章）。对于隐匿性后间隔或左后间隔旁道杰克曼教授最喜欢的起搏部位是冠状静脉外侧，也是植入CRT导线的手术者最喜欢的起搏部位（图5.7B)。从冠状静脉外侧起搏延长VA间期，揭示旁道电位和最早心房激活的部位。如果CS太小，不能容纳起搏导管和标测导管， 可经主动脉逆行将起搏导管放置在左室外侧基底部。

Figure 5.7. Effects of wavefront change on AV or VA intervals of septal APs. A. In a patient with an anteroseptalAP, RAA pacing produced a longer AV interval at the site of earliest ventricular activation, indicating that the atrial end is inferior and septal to the ventricular end. B. In a patient with a posteroseptal AP, pacing from posterolateral coronary vein produced the longest VA interval at the site with earliest atrial activation (in red box), indicating that the ventricular end is more posterior and septal to the atrial end.

图5.7. 波振面反向变化对间隔旁道AV和VA间期的影响。A.在前间隔型旁道患者中，右心耳起搏在最早的心室激动部位产生较长的房室间期，表明心房插入端较心室插入端更靠低位间隔。B.在后间隔型旁道患者中，从冠状静脉后外侧起搏在心房最早激动的部位产生最长的VA间期（红色方框中），表明心室插入端较心房插入端更靠后间隔

Figure 5.8. Far-field and near-field AP-P. A. A small far-field AP-P (red arrow) was recorded on the mapping catheter.AblationheretransientlyblockedtheretrogradeAPconduction.B.Left panel:Mapping catheter positioned at the mitral annuls.The proximal electrode pair (MAPp) recorded far-field, continuous potentials. Right panel: After adjusting the position of the mapping catheter, the proximal electrode pair (MAPP) recorded a far-field AP-P (blue arrow). The distal electrode pair (MAPD)recorded a sharp AP-P (red arrow). However, the AP-P was on the proximal ring electrode (UNI-2), not the distal electrode(UNI-1). This position is not ideal for ablation. AP conduction was eliminated immediately when the mapping catheter wasrepositionedandtheAP-P was recorded on the distal electrode(UNI-1).

图5.8. 远场和近场旁道电位。A.标测导管上记录小远场旁道电位（红色箭头）。消融此处暂时阻断了旁道的逆传。B.左图：标测导管置于二尖瓣环。近端电极对(MAPp)记录到远场连续电位。右图：调整标测导管位置后，近端电极对(MAPP)记录到远场旁道电位（蓝色箭头）。远端电极对(MAPD)记录了一个尖锐的A旁道电位（红色箭头）。但是旁道电位在近端电极(UNI-2)上，而不在远端电极(UNI-1)上。这个位置对于消融来说并不理想。当标测导管重新定位后，立即消除旁道传导，并在远端电极(UNI-1)上记录到旁道电位。

An important point that cannot be overemphasized is that differential pacing should be delivered near the annulus in order to facilitate the paced wavefront to engage the AP as all APs are located along the annulus.Dr.Jackmannever paces from the RA freewall or RV apex to map an AP. One may think differential pacing to select the ideal ablation target is too time-consuming; however,in Dr.Jackman’s experience,failure to effectively prolong the AV or VA interval accounts for 60-70% AP ablation failure!! This approach is definitely worthwhile if operators cannot find a good ablation target due to short AV or VA interval.

In patients with prior ablation failure, local atrial or ventricular potential may have multiple components resulting from prior ablation.Poor choice of pacing sites may produce AV or VA fusion, misleading the operator to target the component of the local EGM that does not connect to the AP.

重要的一点是，差异起搏应该在房室环附近进行，以便于起搏波振面便于进入旁道，因为所有AP都位于房室环附近。杰克曼博士从不从右房游离壁或右室心尖起搏来标测旁道。有人认为差异起搏选择理想的消融靶点太耗时；然而，根据杰克曼博士的经验，未能有效延长AV或VA间期占旁道消融失败的60-70%！！如果术者由于AV或VA间期短而无法找到好的消融靶点，这种方法肯定是值得的。在先前消融失败的患者中，局部心房或心室电位可能由于先前消融导致产生多种成分。起搏部位选择不当可能产生AV或VA融合，误导术者以远离旁道的位置作为靶点。

ValidationofAP-P

AP-P验证

The site recording a sharp AP-P is always Dr. Jackman’s first choice of ablation target. An AP-P is almost always a sharp potential(similar to or just a bit wider than a HB potential)but the amplitude of the AP-P varies substantially. In Dr. Jackman’s experience, the largest AP-P is often recorded in patients with Ebstein’s a nomaly. If arounded AP-P is recorded,it probably is a far-field AP-P(Figure5.8A);a sharp AP-P maybe recorded a few millimeters away.

If anAP-P is no where to be found(e.g.an epicardialAP)or the AP does not traverse the annulus with an oblique angle, the site of earliest atrial or ventricular activation is his second choice of ablation target. Dr. Jackman does not prefer to target the site of AV or VA fusion for there a sons already discussed. The only exception is when the AV or VA interval has been maximized by differential pacing. A site showing VA fusion is not because the local ventricular activation is late but the AP-P or atrial activation is early. A VA fusion site like this represents the V-AP-A junction but one cannot diferentiate an AP-P from the local atrial and ventricular potential. Ablation there oftenworks as well.

记录尖锐旁道电位位置的常常是Jackman教授的首选消融靶点。旁道电位几乎总是一个尖锐的电位（类似于或仅仅比HB电位宽一点），但旁道电位的振幅变化很大。根据杰克曼教授的经验，最大的旁道电位经常在Ebstein畸形的患者中记录到。如果记录到一个圆钝的旁道电位，它可能是一个远场旁道电位（图5.8A)；一个尖锐的旁道电位可能就在此处不远。

如果没有发现旁道电位（如心外膜旁道)，或旁道没有以斜行穿过房室环，最早的心房或心室激动部位是他消融靶点的第二选择。杰克曼教授不喜欢将AV或VA融合的部位作为消融靶点，原因上述已经讨论过。唯一的例外是当AV或VA间期已经通过差异起搏达到最大值。显示VA融合的部位不是因为局部心室激动晚，而是因为旁道电位或心房激动早。像这样的VA融合部位代表V-AP-A连接，但不能将旁道电位与局部心房和心室电位区分开来。在这里消融也经常起作用。

Differentiating an AP-P from a local ventricular or atrial potential can be a daunting task. Figure 5.9illustratesthetechniquewhichDr.Jackman use stop rove the potential of interestisindeedanAP-P. In brief, this technique is to deliver single atrial extra-stimuli (AES) or single ventricular extra-stimuli (VES) to bdissociate the potential of interest from the local atrial and ventricular potential. If the potential of interest is neither the local atrial or ventricular potential, it has to be an AP-P. Certainly, operators need to ensure the potential of interest is not a HB potential before starting ablation.

In a manifest AP, particularly ananteroseptalAP, the HB potential may look like a sharp AP-P. The easiest way to differentiate a HB potential from an AP-P is to deliver decremental RA pacing. If the sharp potential of interest is progressively delayed along with more preexcitation,this potential is a HB potential.For a concealed AP,it is obvious that during sinus rhythm,this sharp should not be simultaneous with the HB potential.

从局部心室或心房电位鉴别旁道电位是一项艰巨的任务。图5.9阐述了杰克曼教授用来证明潜在兴趣电位确实是旁道电位的技术。简单地说，这种技术是通过发放单个额外心房刺激(AES)或心室刺激(VES)，将感兴趣的电位从局部心房和心室电位中分离出来。如果兴趣电位既不是局部心房电位，也不是局部心室电位，则肯定是旁道电位。当然，在开始消融之前，操作者需要确保兴趣电位不是HB电位。在显性旁道患者中，特别是前间隔区旁道，HB电位可能看起来像一个尖锐的旁道电位。区分HB电位和旁道电位最简单的方法是发放递减右房起搏。如果感兴趣的尖锐电位随着提前激动而逐渐延迟，这就是HB电位。对于隐匿性旁道患者， 很明显，在窦性心律期间，这一尖锐电位不应与Hb电位同时出现。

Figure 5.9. Pacing maneuvers to verify an AP-P. A. A sharp potential was noted (red arrow) during atrial pacing (S1). A ventricular extra-stimulus (VES, S2) advanced the local ventricular potential (empty red arrow) without affecting the sharp potential of interest, proving that this sharp potential was not part of the local ventricular potential. B. During atrial pacing, amuchearlierVES(S2)engagedtheventricularendoftheAP, allowing retrogradeAPconductionfromtheventricletoAP.The interval between the local atrial activation and sharp potential was shortened from 35 ms to 20 ms, proving that this sharp potential of interest was not part of the local atrial potential.

图5.9. 验证旁道电位的起搏方案。A.在心房起搏时出现的一个尖锐的电位（红色箭头）(S1)。一个心室额外刺激(VES，S2)使局部心室电位（空红箭头）提前，而不影响感兴趣的尖锐电位，证明这种尖锐电位不是局部心室电位的一部分。B.在心房起搏期间，更早的心室额外刺激(S2)进入旁道的心室插入端，允许旁道从心室插入端逆行传导到旁道。局部心房电位与尖锐电位之间的间隔从35 ms缩短到20 ms，证明此尖锐电位不是局部心房电位的一部分。

Another maneuver that is easy to implement but may not prove or disprove the potential of interest is to induce nonsustained AVRT or deliver decremental pacing until AP conduction blocks(Figure5.10).Then,the operator can compare the EGM of AP conduction and AP block to identify the critical element of APconduction. The author prefers to start decremental pacing at a CL 30-40 ms longer than the AP block CL to ensure good catheter stability and stable local atrial or ventricular EGMs at the time of AP block for accurate comparison between the AP conducted beat and AP blocked beat.

If a sharp potential at the end of the local ventricular potential disappeared when retrograde AP conduction blocks, that sharp potential cannot be part of the ventricular potential, suggestive of an AP-P or a very early atrial potential (Figure5.10A);

ablation there has a high likelihood to be successful. However, the limitation of this technique is that if the potential of interest persists at the time of retrograde AP conduction block,this potential can still bean AP potential(Figure5.10B)because the site of AP conduction block is between the AP and atrium. The author avoids using the S1S2 protocol because when S2 is delivered, the catheter tends to move. The local activation potential of the S2 may look different from that of S1,making comparison between the conducted beat and blocked beat a difficult(Figure5.10C).

另一个容易实施但可能不能证明是否是兴趣电位的方法是诱导非持续性AVRT或递减起搏直到旁道传导阻滞（图5.10）。然后，术者可以比较旁道传导和旁道阻滞的EGM来识别旁道传导的关键成分。为了准确比较旁道传导搏动和旁道阻断搏动，笔者建议以比旁道完全阻滞时周长长30-40 ms的周长开始递减起搏，以确保旁道阻滞时导管稳定性佳，在旁路传导或阻滞时局部心房或心室电位稳定。

如果局部心室电位末端的尖电位在逆行旁道传导阻滞时消失，该尖电位不可能是心室电位的一部分，提示其为旁道电位或极早期心房电位（图5.10A)；在那里消融有很大成功的可能性。然而， 这种技术的局限性在于，如果在逆行旁道传导阻滞时兴趣电位持续存在，这个电位仍然可以是旁道电位（图5.10B)，因为旁道传导阻滞的部位在旁道和心房之间。笔者建议避免使用S1S2刺激，因为当S2刺激时，导管易于移动。S2的局部激动电位可能看起来与S1不同，使得传导和阻滞时之间的比较变得困难（图5.10C)。

Based on Dr. Anton Becker’s description, APs appear to be an extension of the atrial myocardium.The atrial end may have multiple branches that Dr. Becker called it “mangrove tree roots”. This finding leads to a common observation that over retrograde AP conduction,are latively large area may record earliest atrial activation, particularly when widely-spaced electrode catheters are used. Antegrade conduction from atrium to AP is usually robust.

For a left free wall AP, antegrade AP conduction block typically occurs at the ventricular end (AàAPàblock); conduction block like this occurs in only half of the patients with a right freewall AP. Such differences may result from a larger source-sink mismatch of left free wall APs caused by a larger LV mass. If antegrade AP conduction block occurs at the ventricular end (the AP-V junction), an antegrade AP potential may still be recorded in a concealed AP.

根据Anton Becker教授的描述，旁道似乎是心房肌的延伸。心房插入端可能有多个分支，Anton Becker博士称之为“红树林树根”。这一发现导致了一个常见的现象，即在逆行旁道传导中，相对较大的区域可能记录最早的心房激动，尤其是当使用大间距电极导管时。心房到旁道的顺行传导通常是稳定的。对于左侧游离壁旁道，旁道前传阻滞通常发生在心室末端(A→AP→阻滞）；像这样的传导阻滞只发生在一半的右侧游离壁旁道的患者中。这种差异可能是由较大的LV质量引起的左侧游离壁旁道source-sink错配造成的。如果顺行旁道传导阻滞发生在心室插入端（旁道-V连接），在隐匿性旁道中仍可能记录到顺行性旁道电位。

Localization of AP by preexcitation pattern

预激定位

There is a wealth of literature about predicting the location of an AP based on the preexcitation pattern. Decades ago, one of Dr. Jackman’s favorite fellows, Dr. Xunzhang Wang, discovered that if lead V1 begins with a small, broad r wave, followed by two downward deflections, it is almost always a right free wall AP (Figure 5.11A-C). This observation holds true in the vast majority of cases. It is not uncommon for a patient who was referred to the OU-EP group for an anteroseptal AP ablation with an ECG showing that lead V1 began with a small but broad r wave, followed by two downward deflections. Ablation site was always not adjacent to the septum.

Dr. Jackman also uses the delta wave in aVF to help determine if the ventricular end is superior or inferior to the CS. If the delta wave in aVF is positive, the AP is usually above the level of the CS ostium; if it is negative, the AP is usually at or below the level of the CS ostium.

已有大量文献报道了关于根据预激波形预测AP的位置。几十年前，Jackman博士最喜欢的同事之一王勋章博士发现，如果V1导联以一个小而宽的r波开始，然后是两个向下的偏转，那么它很可能一个右游离壁AP（图5.11A-C）。这一观察结果在绝大多数情况下都成立。对于转诊至OU-EP组进行前间隔AP消融术的患者来说，心电图显示V1导联开始时出现一个小但宽的r波，随后出现两次向下偏转，这并不罕见。消融部位总是不靠近间隔。Jackman博士还使用aVF导联中的delta波来帮助确定心室插入端高于或低于CS。如果aVF中的delta为正向，AP通常高于CS口的水平；如果是负向，AP通常处于或低于CS口的水平。

Fig 5.11. ECG localization of right-sided APs. A. A right anterior AP. Lead V1 began with a small, broad r wave (blue arrow) followed by two downward deflections (red arrows). This is a typical pattern for a right free wall AP. The score of the delta wave polarity in lead II, III and aVFis 3, indicating that this AP is superiorly located. The red star indicates the location of the AP where it was successfully ablated. B. A right lateral AP. C. A right posterolateral AP. D. A right midseptal AP. Note that the delta wave in lead V1 begins with a q wave, different from a free wall AP shown in A-C. E. An anteroseptal AP.

The delta wave also begins with a q wave. F. A posteroseptal AP using the middle cardiac vein as part of the AP-LV connection. Note that the delta wave in lead V1 begins with an r wave and the QRS complex exhibits an rs morphology, suggestive of a left-sided AP. Inset: location of successful ablation and ECG of lead V1.

图5.11. 右侧旁路的心电图定位。A.右前旁路。V1导联开始时出现一个小但宽的r波（蓝色箭头），随后出现两次向下偏转（红色箭头）。这是典型的右侧游离壁旁路。根据II, III and aVF导联Delta波极性积分3分，提示旁路位于高位。成功消融靶点位于红色星形部位。B.右侧游离壁旁路。C.后游离壁旁路。D.中间隔旁路。注意V1导联Delta波起始是q波，不同于A-C图中的游离壁旁路。E.前间隔旁路。Delta波起始为q波。F.后间隔旁路，旁道的左心室插入端位于心中静脉。注意V1导联Delta波起始是r波，QRS波的形态是rs型，提示旁道位于左侧。

By combining Dr. Jackman’s algorithm with several published algorithms, the author uses the following criteria to predict the ventricular end of an AP.

1. Analyze only the first 30-40 ms of the delta wave, not the polarity of the entire QRS complex because the rest of the QRS complex may be formed by AVN conduction. Sometimes, it can be difficult to determine where delta wave begins. Dr. Jackman uses the onset of the delta wave in lead I to examine the beginning of the delta wave in other leads.

2. Look at lead V1 first. If V1 starts with a QS pattern and V2 shows a positive delta wave (early precordial transition), it is almost always a septal AP (Figure 5.11D-E). If V1 shows an rS pattern, the larger or wider the r wave, the more likely it is an AP at a safe distance from the AV node.

3. Score the delta wave in lead II, III an aVF to determine how superior or inferior this AP is located. If the delta wave is positive, give it a score of 1. If it is negative, give it a score of -1. Iso-electrical delta wave gets a score of 0. Adding the scores up, an anteroseptal AP or anterior AP usually gets a score of 3; a posteroseptal AP or posterior AP usually gets a score of -3. Mid-septal or lateral free-wall AP usually gets a score between +1 to -1 (Figure 5.11).

4. If the delta wave is positive in both lead I and aVL, it is usually a right-sided AP (Figure 5.11). However, a left posteroseptal or left posterior AP can produce a positive delta wave in both lead I and aVL because the preexcitation wavefront propagates toward these two leads. Only detailed mapping can differentiate a left posteroseptal AP from a right posteroseptal AP.

5. For a left free wall AP, the delta wave in lead V1 usually is isoelectric or positive. The entire QRS complex of V1 usually exhibits an atypical RBBB pattern or an rs/RS pattern (Figure 5.12). The QRS complex of the V1 lead is more likely to be rS or QS in the presence of a right-sided AP.

6. For a left free wall P, if the delta wave is negative in both lead I and aVL, it is most likely an AP located along the 1:00 to 2:00 position along the mitral annulus (Figure 5.12A). If the delta wave is positive in both lead I and aVL, it is most likely an AP located along the posteroseptal or posterior mitral annulus because the preexcitation wavefront propagates toward these two leads (Figure 5.12B).

7. The baseline preexcitation pattern can be very different from that in preexcited AF or antidromic AVRT because of lack of the contribution from antegrade AVN conduction. In the presence of full preexcitation, the entire QRS complex is formed by antegrade AP conduction; the polarity of the QRS complex may look completely different from that in sinus rhythm when only the first 30-40 ms of the QRS complex is formed by antegrade AP conduction. However, the polarity of the 40 ms of the QRS should be identical. Most, if not all, of the published ECG algorithms were based on sinus rhythm, not full preexcitation.

通过将Jackman博士的算法与几种已发表的算法相结合，作者使用以下标准来预测AP的心室插入端。

1.只分析Delta波的前30-40ms，而不是整个QRS复合波的极性，因为QRS复合波的其余部分可能由AVN传导形成。有时，很难确定Delta波的起点。Jackman博士利用I导联中Delta波的起始来验证其他导联中Delta波的起始。

2.先看V1导联。如果V1以QS开始，而V2显示正向Delta波（心前区移行较早），则几乎总是间隔AP（图5.11D-E）。如果V1显示rS模式，r波越大或越宽，旁道有可能位于距离房室结的较为安全的距离。

3.对导联II、III和aVF中的Delta波进行评分，以确定该AP的上下位置。如果Delta波是正向的，打1分。如果是负向的，打-1分。等电位线Delta波得0分。将分数相加，前间隔AP或前AP通常得到3分；后间隔AP或后位AP的得分通常为-3。中间隔或外侧游离壁AP的得分通常在+1到-1之间（图5.11）。

4.如果δ波在导联I和aVL中均为正向，则通常为右侧AP（图5.11）。然而，左后间隔或左后AP也可在导联I与aVL产生正向δ波，因为预激波振方向与这两个导联相同。只有详细的标测才能区分左后间隔AP和右后间隔AP。

5.对于左游离壁AP，导联V1中的δ波通常是等电位线的或正的。V1的QRS波群通常表现为非典型RBBB型或rs/RS型（图5.12）。在右侧AP存在的情况下，V1导联的QRS波更可能是rS或QS。

6.对于左侧游离壁P，如果I导联和aVL导联的δ波均为负向，则很可能是位于二尖瓣环1:00至2:00位置的AP（图5.12A）。如果I导联和aVL导联的δ波均为正向，旁道的位置很可能是位于二尖瓣环后间隔或二尖瓣后壁，因为预激波振方向与这两个导联相同（图5.12B）。

7.由于缺乏AVN前向传导的贡献，基线预激波形可能与预激伴房颤或逆向AVRT发作时非常不同。在完全预激的情况下，整个QRS复合波由AP前传形成。QRS复合波的极性可能与窦性心律中只有前30-40ms由AP前传形成的QRS复合波的极性完全不同。然而，40ms的QRS波的极性应该是相同的。大多数（不是全部）已发表的心电图算法都是基于窦性心律，而不是完全预激。

Figure 5.12. ECG localization of left-sided APs. A. A left anterior AP located at the 1:30 o’clock position along the mitral annulus. Note that the delta waves in both lead I and aVL was negative. B. A left posterior AP located at the 4:30 o’clock position along the mitral annulus. Note that the delta wave was positive in both lead I and aVL. The morphology of V1 (positive delta wave, an R complex) helps predict that this is a left free wall AP. C and D. In a patient with a left posterolateral AP located at the 4:00 o’clock position along the mitral annulus. Note that in the baseline state, there was only minimal preexcitation. During preexcited tachycardia, the preexcitation looked different from that in the baseline state but the polarity of the first 40 ms was identical.

图5.12 左侧旁路的ECG。A.位于二尖瓣环1:30位置的左前旁路。注意I导联和aVL导联的δ波均为负向。B.位于二尖瓣环4:30的左后旁路。注意I导联和aVL导联的δ波均为正向。V1导联形态（δ波正向，R波复合）提示旁道位于左侧游离壁。C和D.旁道位于左后游离壁，二尖瓣环4:00方向。注意在基线上只有很小的预激波。在预激伴心动过速发作时，预激波看起来与基线水平不同，但前40毫秒时完全相同的。