摘要：普通型心房扑动(AFL)的完整折返环路以及界嵴(CT)和AFL的关系仍不太清楚，笔者应用电解剖(CARTO)标测系统执行两项研究。Ⅰ：对12例持续AFL的病人实施右房CARTO标测及多部位拖带。于三尖瓣环(TA)周围测量传导速度。双电位(DP)位于右房后下壁，相当于解剖上的界嵴，从下腔静脉(IVC)与心房肌的连接处向上、稍前延伸，其长度为40.9±7.9 mm。所有病人的DP间期从上至下逐渐增加。在9例逆向AFL病人中，右心耳后基底部的后方一狭长心肌位于折返环内，结果来自右心耳基底前、后方的两个心房激动波融合于右房下游离壁。在另3例病人中(1例顺钟向、2例逆钟向)右心耳基底部后方未发现位于折返环内，迫使折返环仅绕三尖瓣与右心耳基底部前方之间的心肌兴奋右房下游离壁。在AFL的折返环中，没有固定的缓慢传导区，大部分病人的缓慢传导区位于间隔部和侧壁。Ⅱ：对7例普通型AFL及6例非AFL病人，在冠状窦起搏下，标测右房后壁。通过在右房重建中出现DP确认CT。以600，300 ms周长以及静脉注射氟卡胺(1 mg/kg)后以600 ms周长起搏冠状窦，分别测量CT上、中、下部位的刺激信号至双电位中第一及第二个心房激动波的传导时间(SD₁及SD₂)和此部位的电位间期(DPI)。在AFL病例中，与以600 ms周长起搏冠状窦时相比，以300 ms以及静脉注射氟卡胺后以600 ms周长起搏冠状窦时，CT的SD₂和DPI从上至下逐渐增加。结论：①右心耳基底前、后方的心房激动波传导存在差异，结果导致了AFL的2种不同的折返环。②在人类的AFL折返环中，没有固定的缓慢传导区，缓慢传导区位于沿TA的间隔部和侧壁。③在AFL折返环路中，CT是一功能性解剖障碍；在没有AFL的病人中，CT被证实为是一缓慢传导区。④频率依赖性和氟卡胺诱导的跨CT的功能性传导阻滞是一种常见现象，此可能是临床AFL的诱发和维持的触发因素。

分类号：R319R541.7⁺5R331.3⁺8文献标识码：A

文章编号：1007—2659(2000)01—0006—06

New Electrophysiologic Phenomena in Patients With Common-type Atrial Flutter.

OUYANG Fei-fanKarl-Heinz Kuck.

Abstract：The complete reentry circuit of common-type atrial flutter (AFL) and relationship of crista teminalis (CT) and AFL are not clear.The two studies were perfomed by using the electroanatomical (CARTO) mapping system.Ⅰ:The right atrial mapping and extensive entrainment was performed in 12 patients with ongoing AFL.Conduction velocities was measured around the tricuspid annulus (TA).Double potentials (DP) in the poteroinferior wall extended 40.9±7.9 mm from the junctio of inferior vena cava (IVC) and the right atrium (RA) and DP interval progressively increased from superior to inferior direction in all pts.In 9 pts with counterclockwise AFL a septal activation wavefront spread to the RA appendage (RAA) anteriorly and posteriorly and the two wavefront fused at the free wall before entering the isthmus between the TA and IVC.In other 3 pts the two wavefront fused at posteroinferior RAA with extinction of the posterior wavefront.No fixed zone of slow conduction was found in AFL reentry circuit,lateral and septal annus was a one of slow conduction in majority pts.Ⅱ:The posterior RA was mapped during pacing of the coronary sinus (CS) in 7 pts with AFL and 6 pts without AFL.The CT was identified by the presence of DP in reconstruction of the RA.The stimulus-to-1st component of DP (SD₁),the stimulus-to-2nd component of DP (SD₂),and the DP interval (DPI) were measured at the superior,middle and inferior aspects of CT during CS pacing with CL 600 ms;300 ms;and CL 600 ms after intravenous (i.v.) administration of 1 mg/kg flecainide.In pts with AFL,SD₂ and DPI was progresively increased from superior to inferior aspect of CT at CS pacing with CL 300 ms and after i.v.flecainide compared to those at CS pacing with CL 600 ms,but in pts without AFL SD₂ and DPI was not significantly increased at CS pacing with 300 ms and after i.v.flecainide.Conclusion:1.Conduction difference between the anterior and posterior wavefront of RAA resulted in two different reentry circuit in pts with AFL;2.No fixed zone of slow conduction was found in human AFL circuit,but a zone of slow conduction was located in lateral and septal aspect along the TA;3.CT is a functional anatomical barrier in AFL circuit,in pts without AFL,the CT proved to be an ares of slow conduction;4.Ratede-pendent and flecainide-induced functional conduction block across the CT is a common phenomenon and may provide a triggering factor for initiation and maintenance of clinical AFL.［Chinese Journal of Cardiac Pacing and Electrophysiology,2000,14(1):6～11］

Key Words：Atrial flutter,common-typeCARTO systemElectroanatomical mappingEntrainment mappingZone of slow conductionDouble potentialCrista teminalisElectrophysiologyCatheterablation,radiofrequency current▲

普通型心房扑动(简称房扑)是一种大折返房性心动过速，其折返环位于右房，包括逆钟向和顺钟向型房扑。三尖瓣和下腔静脉形成的峡部是折返环的关键部位，射频消融此峡部可治愈房扑，其成功率达95%^［1～9］。若射频消融以峡部双向阻滞为终点，其复发率约5%左右^［10］。最近研究显示三尖瓣环和界嵴(crista terminalis)是房扑两个固定和/或功能性解剖屏障^［1～3］，但界嵴的电生理特性与房扑的关系尚不清楚，且对峡部是否为缓慢传导区仍有争论。我们电生理室通过使用新的标测系统——电解剖标测系统(Electroanatomical mapping systm，即CARTO_TM mapping system)研究房扑的折返环、折返环内传导速度及房扑患者与未有房扑患者界嵴的电生理现象的差异，以期解释为什么仅有一部分人发生房扑这一电生理现象。本系列研究由两大部分组成：普通型房扑的折返环、界嵴的电生理特性。

Ⅰ普通型房扑的折返环

1资料与方法

12例持续性房扑患者，其中男8例、女4例，年龄60±8岁。所有患者无心脏外科手术及射频消融史。无明确结构性心脏病证据者9例、冠心病2例、扩张型心肌病1例。停用抗心律失常药物至少5个半衰期以上。

电生理检查及CARTO标测：穿刺左、右股静脉及左锁骨下静脉，置7F Jackman电极于冠状窦内、6F 10极Webster His束旁电极于His束部位，另外置7F 20极Webster A—20电极于右房游离壁，且近可能靠近三尖瓣环。CARTO标测中，空间定位电极置于病人背部，时间定位心房电信号来源于冠状窦内稳定的心房电信号。为了确保右房电解剖标测的精确性，常规穿刺右颈内静脉，以期使Biosense Navi—Star标测电极可经右股静脉或右颈内静脉到达右房内任何部位。标测采用双极和单极同时记录，滤波范围分别为10～400 Hz和0～400 Hz。

双电位定义为有两个恒定的电位，且两者间的等电位线长于20 ms。所有病人完成右房电解剖重构后，必须进行右房多部位拖带标测以检测此处是否在房扑的折返环内。这些部位包括三尖瓣环(峡部、侧壁、间隔及前壁)、房间隔、冠状窦口的前方及后方、右心耳内及基底部的前方和后方。我们定义某标测点位于房扑折返环内的标准是：起搏后停顿间期(post-pacing interval,PPI)-房扑周长＜30 ms，且(刺激信号-P波间期)-(局部传导时间-P波间期)＜30 ms。传导速度的测量必须确保两标测点位于折返环内，且两点间距离少于3 cm。另外测量峡部间隔部和侧壁的宽度以及计算机自动分析的右房容积。

统计学处理：所有参数均采用±s表示。

2结果

12例持续性房扑，其中11例为逆钟向房扑、1例为顺钟向房扑。标测点为258±35(196～304)个，房扑周长为271±37(233～350) ms，被标测的房扑周长为96.1%±2.1%(93%～100%)。电解剖重构的右房容积为118±24(92～160)ml。峡部宽度：间隔部为20.9±5.2(12～29) mm、侧壁为27.5±5.8(19～34) mm。所有病人三尖瓣环都构成其房扑的解剖屏障。PPI长于房扑周长30 ms部位分布在冠状窦口后方、高位右房后壁及右心耳内。3例病人(其中1例顺钟向和2例逆钟向房扑)右心耳基底部后方未发现位于折返环内，迫使折返环仅绕三尖瓣与右心耳基底部前方之间的心肌兴奋右房下游离壁(附图A)；另9例病人，右心耳后基底部的后方一狭长心肌位于折返环内，结果来自右心耳基底前方和后方的两个心房激动波融合于右房下游离壁(附图B)。

附图