心房肌的复极与阵发性心房颤动发生机制的实验研究

目的　对在体犬左、右心房肌的复极时间进行研究 ,探讨阵发性心房颤动 (房颤 )发生与维持的潜在机制。方法　记录基础心律、非程序刺激及早搏刺激 (SR、S1 、S2 )时 1 4只犬左、右心房的单相动作电位 (MAP)和有效不应期 (ERP) ,测量每个动作电位的幅度和动作电位时程 [复极达90 %、80 %、5 0 %时的动作电位时程 (ms,APD90 、APD80 、APD50 ) ]。并在记录过程中同时观察房颤的诱发情况。结果　记录满意MAP信号 1 2例 ,共标测 2 6点 (右房 1 7点 ,左房 9点 ) ,MAP振幅平均(6 98± 1 76 )mV ,左心房APD90 和APD50 小于右心房 [(1 5 7 4± 4 3 5 0 )ms比 (1 70 9± 37 9)ms ,P <0 0 5 ;(88 4± 1 9 1 )ms比 (1 0 0 1± 2 1 2 )ms,P <0 0 5 )。其中左房刺激发作 38阵 ,明显多于右房 2 3阵 (P <0 0 5 )。由左房诱发房颤的早搏的偶联间期明显比在右房诱发的短 (P <0 0 5 )。起源于左房的房颤的早搏参数小于起源于右房的 (P <0 0 5 )。结论　左、右心房间具有MAP的异质性的复极特性 ,是诱发折返、发生和维持房颤的基质。     

房室结慢径消融对心房电生理性质的影响

Objective The ablation of the atrioventricular node slow pathway may reduce the inducibility of atrial fibrillation (AF) ,but the mechanisms remain unknown. We tried to investigate the impact of ablation on atria refractory period, and to elucidate the underlying mechanism. Methods Thirty-two patients with atrioventricular node reentrant tachycardia (AVNRT) were enrolled in the study. Atria effective refractory period (ERP) and vulnerable window (VW) at high right atrium (HRA),inferior right atrium (IRA),distal (CSd) and proximal CS (CSp) ,as well as sinus rate (SR) and effective refractory period of fast pathway (FERP) were measured before and after ablation. Results ( 1 ) After ablation, the ERP at HRA did not change:(214. 4 ± 35. 1 ) ms, (213.4 ± 37. 3) ms, P = 0. 6, on the other hand, the ERPs at following sites were significantly prolonged:CSp(218. 1 ±21.8)ms, (235.3 ± 23.6) ms,P ＜0. 0001 ;CSd(230. 9 ±21.0) ms, (244. 7 ±25. 1)ms,P＜0. 01;IRA(198.8 ±26.7)ms,(219.7 ±28. 7) ms,P ＜ 0.005,respectively. (2) The VW of HRA remained unchanged after ablation, while the VWs of CSp, CSd and IRA trended to decline despite no statistic significant. (3)SR showed a little increasing but without statistic significant after ablation (P = 0. 17 ).(4) ERP of fast pathway was significantly decreased after ablation: ( 391 ± 55 ) ms, ( 369 ± 78 ) ms, P ＜ 0. 01.Conclusions The decrease of ERPs at CS and IRA, as well as F-ERP after ablation may decline the inducibility of atrial fibrillation and indicates regional vagal denervation to the atrium.     

肺静脉电隔离对阵发性心房颤动患者P向量环的影响

目的探讨成功的肺静脉电隔离对心房除极的影响。方法记录接受环肺静脉电隔离术的18例阵发性心房颤动(PAF)患者术前及术后第1天窦性心律时的心向量图。测量P环的运行时间、P向量环在正交导联额面(F)、水平面(H)、左侧面(LS)的最大振幅及方向。同时记录P环从运行开始后每10ms的除极振幅。结果肺静脉隔离术后P环F最大振幅较术前降低(0.109±0.038mVvs0.128±0.040mV,P0.05)。P环运行时间,H及LS的最大振幅,F、H、LS的最大振幅方向,术前术后无差异(P0.05)。消融成功组(n=12)术后P环H最大振幅较术前降低(0.092±0.019mVvs0.122±0.030mV,P0.05),而术后复发组(n=6)则无明显变化。肺静脉隔离术后P环振幅降低发生在P环运行至40～80ms的部分,即P向量环的中部。结论PAF病人在肺静脉电隔离成功后P环最大振幅发生改变。     

心房肌复极的电整复性与阵发性心房颤动发生机制的实验研究

Objective Electrical restitution was believed to be a determinant responsible for the stability of heart rhythm. Although numerous studies focused on the role of action potential duration restitution (APDR) in the initiation and maintenance of ventricular fibrillation (VF), the relationship between atrial APDR and atrial fibrillation (AF) has not been fully understood. This study aims to investigate the characteristics of APDR of left atrium (LA) and right atrium (RA) in canines and the relevance to induction of AF. Methods Monophasic action potential (MAP) was recorded from LA and RA in 14 canines using the MAP recording-pacing combination catheter. APDR, plotted as action potential duration (APD) on the preceding diastolic interval (DI), was assessed by use of programmed stimulation with a single extrastimulus (S_1S_2) at LA and RA. Episodes of AF were recorded and analyzed. Results APD_(90) was significantly shorter in the LA than that in the RA [( 157.4 ± 43.5 ) ms vs. ( 170. 9 ± 37. 9)ms, P < 0. 05]. The mean slope of the APDR curve by S_1S_2 in the LA was significantly greater than that in the RA ( 1.3 ±0. 4 vs. 0. 9 ± 0. 3, P < 0. 05 ). The incidence of induced AF was significantly higher in the LA than in the RA (11/18 vs. 7/18, P < 0. 05). Conclusions The APDR and MAP characteristics are not uniform between atriums, which may be one of the important mechanisms responsible for the initiation of AF. Heterogeneity of APDR between LA and RA might create critical gradients or a dispersion of repolarization and subatrate for re-entrant arrhythmias and vulnerability to AF.     

装上起搏器,圆当母亲梦

怀孕6个月的王娟,丝毫没有快为人母的兴奋,反而整天忧心不已.原来,在这之前,她已经流产过2次,都是因为心跳过慢,不适合分娩,而被迫进行人工流产.最近一次孕前检查,她又被发现心跳每分钟不到50次,而且还有Ⅲ度房室传导阻滞.     

装上起搏器，圆当母亲梦

怀孕6个月的王娟,丝毫没有快为人母的兴奋,反而整天忧心不已。原来,在这之前,她已经流产过2次,都是因为心跳过慢,不适合分娩,而被迫进行人工流产。最近一次孕前检查,她又被发现心跳每分钟不到50次,而且还有Ⅲ度房室传导阻滞。这一次又会悲剧重演吗？王娟想当母亲的愿望何时能实现呢？     

低钾血症患者血清钾浓度与心电图改变的相关性分析

目的 探讨低钾血症患者的血清钾浓度和心电图改变的相关性及二者对诊断低钾血症的临床价值.方法 对85例低钾血症患者的血清钾浓度与心电图改变进行对照分析研究.结果 心电图提示低血钾75例,诊断准确率为88.2%,血清钾测定显示低血钾54例,诊断准确率为63.5%,其中44例心电图检查与血清钾测定均提示低血钾,31例心电图提示低血钾但血清钾测定正常,10例心电图正常而血清钾低于正常值,两者不符41例.结论 低钾血症患者心电图改变和血清钾浓度有一定的相关性,但并不呈绝对平行关系.心电图较血清钾测定对诊断低钾血症具有一定的优势,但二者不能互相取代,而应相辅相成,互为补充,同时要结合临床资料综合分析,才能做出准确诊断.     

迷走神经与心房颤动的关系

关于心房颤动发生机制和治疗的研究已成为21世纪医学的研究热点问题之一。近十年来，随着心房颤动的射频导管消融（下称消融）治疗所取得的重大进展，人们逐渐认识到心房颤动的发生和维持存在着复杂的机制。心房颤动的触发受到诸多因素的影响，其中迷走神经与心房颤动密切相关。动物实验证实迷走神经刺激或静脉注射乙酰胆碱能够诱发并维持心房颤动，     

阵发性房颤患者大静脉肌袖与心房电连接特征的临床研究

目的：总结阵发性房颤病人肺静脉和／或上腔静脉肌的电生理标测和导管射频消融电隔离的结果，评价国人大静脉肌袖和心房的电连接类型和特点。资料与方法：顽固性阵发性房颤患者45例，在环状标测电极指导下行大静脉肌袖的电位记录、分析以及对能标测到袖电位的大静脉进行开口部的点或段的消融电隔离治疗。根据窦律和心房起搏下的肌袖内环形电极标测到的袖电位的激动顺序以及有效放电对袖电位的影响，总结和分析袖房之间的电连接特点。结果：共标测和／或电隔离肌袖115根，其中肺静脉100根，上腔静脉15根。其中呈单束状电连接43根（38％），双束状电连接54根（46％），多束状电连接12根（10％），环状电连接3根，无电连接3根。结论：根据环状电极标测到的袖电位的激动顺序和对放电的反应，提示袖房之间电连接的类型多为单束状和双束状（84％），说明对于大多数肌袖并不需要行环状消融，而只要在袖房连接处行点或节段性消融即可达到完全袖房电隔离的结果。