普通型心房扑动的新现象

New Electrophysiologic Phenomena in Patients With Common type Atrial Flutter

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± 7.9mm。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 6 0 0 ,30 0ms周长以及静脉注射氟卡胺 (1mg/kg)后以 6 0 0ms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 6 0

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 (SD 1),the stimulus to 2nd component of DP (SD 2),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,SD 2 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 SD 2 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.Rate de 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]