心脏介入治疗与解剖(续)

2 心律失常介入与解剖。2．1 阵发性室上性心动过速的介入治疗。2．1．1 房室结折返性心动过速。正常情况下，房室结是心房、心室之间的唯一电学通道，位于房间隔近三尖瓣环处的前方，Koch三角的前上角。所谓Koch三角是指右房内由Todaro腱、冠状静脉窦口和三尖瓣隔瓣围成的三角形区域。房室结在其中穿过中心纤维体延续为希氏束。房室交界区由三部分组成，即位于房间隔前上区域的前上部分，冠状窦口处延伸而来的后下部分和真房室结。房一结连接区有三个独特的房结束，即上束、中束和侧束。后两融合成近端房结束，并与真房室结相连。上房结束是快径的一部分，中、侧束是慢径的一部分。     

房室结后延伸部形态学特征及与折返性心动过速的关系

目的：研究人房室结双径路，尤其是慢径的解剖学基础。方法：(1)取17例尸检心脏包括房室结在内的房室交界区的组织固定、脱水、包埋后切片，HE和Masson染色，光镜规察(2)由冠状窦151向房室结方向在心内膜下注射墨汁0．5ml，24h后光镜观察墨汁走向?结果：17例标本均可发现房室结，房室结前向形成房室束(His束)，发现47％(8例)有明确向后延伸一左后延伸和彳丁后延伸，35％(6例)仅有右后延伸，1例发现仅有左后延伸，2例未发现有向后延伸。向后延伸南房室结自然延伸而成，其有房室结自然延伸而成，左后延伸朝左行向房间隔，有后延伸行向有，与三尖瓣隔瓣近乎平行，纤维可达冠状窦口附近。结论：房室结后延伸部可能为慢径路，作为房室结折返性心动过速(AVNRT)的射频消融慢径的解剖学基础、     

心脏房室传导阻滞的分型与诊断

对心房与心室间激动传导的改变,传统认为只是房室结的问题,以后由于心内心电图(如希氏束电图等)和通过电生理学、微电极的应用以及电镜对微细的组织学观察等,首先对激动的产生,证实在房室结附近有起搏功能的细胞(即起搏细胞或称P细胞pacemaker cells)存在于心房与房室结的交界部(房-结区)、房室结与希氏束的交界部(结-希氏束区)、希氏束部以及冠状窦的附近区,而房室结本身并无起搏细胞,或只有很少的变异细胞.因此,将房-结区、结-希氏束区、希氏束及冠状赛区以及左心房后部(左房节律发生的部位)统称之为房室交界部或简称交界部,由此产生的心律,统称为交界部(或交界性)心律.     

成人房室交界区过渡细胞束形态学及连接蛋白43和40的表达

目的 观察临床上心律失常常见发生部位及射频消融治疗靶点部位--房室交界区和邻近区域的形态学特点及连接蛋白(Cx)43和40的表达,为心律失常发生机制及可能的有效治疗部位提供形态学依据.方法 10例正常成人心脏,选取房室交界区及其邻近部位,常规石蜡包埋,HE、Masson染色,选定目标部位行Cx43、Cx40免疫组织化学...     

家猪房室交界区的组织学观察

利用石蜡切片 ,HE和 Masson染色 ,光镜观测了 7例猪房室交界区的形态学和组织学特征。家猪房室结位于冠状窦口前方 ,大小为 7.0 2× 2 .6 5× 1.2 9mm3。传导细胞分两类 :1细胞短柱状 ,有时有分叉 ,细胞质内有横纹 ,核相对较大 ,此类细胞多位于结上部和前部 ;2典型的移行细胞 ,多位于结的后部和下部。有 2例存在副房室结。结上部和前部、房室束、右束支内的细胞在形态上介于 Purkinje细胞和心肌之间 ,未见典型的 P细胞。说明猪的传导细胞与其它哺乳动物有差异 ,但不同形式的传导细胞却在履行相同的传导功能     

射频消融治疗阵发性室上性心动过速35例分析

目的 总结射频消融（RFCA）治疗阵发性室上性心动过速（PSVT）35例的经验。方法 左房室旁路消融二尖瓣室侧，右侧房室旁路消融三尖瓣房侧；房室结双径路通过下位法能量递增消融法改良房室结。结果 19例房室折返型心动过速，左侧旁道13条，右侧旁道6条，16例房室结折返型心动过速（AVNRT）首次消融均成功。术后1周1例AVNRT复发，再次消融成功。1～20个月随访无复发及严重并发症。结论 RFCA治疗PSVT安全、有效。     

经食管心房调搏对房室交界区前向连续传导的观察

目的 初步探讨随起搏频率增加时房室交界区前向连续传导的心电图表现特点．方法 对100例经食管心房分级递增起搏中房室交界区前向连续传导的特征分析．结果 房室交界区前向连续传导呈1：1-文氏-2：1以上传导特点变化，极少由1：1直接转为2：1传导．结论 随着起搏频率的增加，房室交界区前向连续传导呈递减性，符合慢反应电位传导特征。     

房室结折返性心动过速与冠状窦及后延伸连接蛋白43表达的关系

目的:探讨房室结折返性心动过速(AVNRT)可能的发生机制。方法:通过电生理检查将新西兰大白兔分为双径路组与非双径路组,以冠状窦及后延伸(PNE)为研究标本,分别做H-E染色及连接蛋白43(Cx43)的免疫组织化学显色。结果:所有标本均可见右后延伸,3例标本可见左后延伸,后延伸Cx43阴性表达,双径路组冠状窦连接蛋白43表达强于左心房。结论:左后延伸构成了左房(二尖瓣环附近)至房室结的传导通路;左后延伸及右后延伸具有慢传导的一些特征;冠状窦可能参与了AVNRT的折返环。     

导管射频消融治疗房室结折返性心动过速

目的总结房室结折返性心动过速（AVNRT）射频消融治疗的经验。方法房室结双径路通过下位能量递增消融法改良房室结慢径。结果房室结折返性心动过速16例，房室结双径路改良全部成功。结论导管射频消融治疗房室结折返性心动过速安全、有效；准确的靶点标侧是成功的关键。     

射频消融猪冠状静脉窦口

摘要： 目的 探讨冠状静脉窦口(coronary sinus ostium, CSO)周围射频消融房室结慢径损伤的病理学特点以及消融能量与损伤范围的关系。方法20只约克猪随机分为实验组及对照组，对实验组采用30W功率以不同时间射频消融CSO周围，光镜观察局部组织病理学改变，统计学方法分析消融能量与损伤范围的关系。对照组麻醉后处死作空白对照。结果 射频消融病灶呈分界清楚的限局性损伤，采用30W功率消融，10S和20S时损伤的面积无明显差异（p>0.05），消融30S及以上时损伤面积明显增大（p<0.05），消融20S及以上时损伤的深度较10S时明显加深(p<0.05）。在300~2400焦耳范围内，消融损伤面积与消融能量两者呈直线正相关关系（r=0.9758，P＜0.05）；损伤深度与消融能量无明显相关关系。结论 CSO周围射频消融房室结慢径， 10~20S以上损伤范围明显增加；300~2400焦耳范围内损伤面积随消融能量的增加而增大。     

Structure-function relationship in the AV junction

In the normal heart, the atrioventricular node (AVN) is part of the sole pathway between the atria and ventricles. Under normal physiological conditions, the AVN controls appropriate frequency-dependent delay of contractions. The AVN also plays an important role in pathology: it protects ventricles during atrial tachyarrhythmia, and during sinoatrial node failure an AV junctional pacemaker can drive the heart. Finally, the AV junction provides an anatomical substrate for reentry. Using fluorescent imaging with voltage-sensitive dyes and immunohistochemistry, we have investigated the structure-function relationship of the AV junction during normal conduction, reentry, and junctional rhythm. We identified molecular and structural heterogeneity that provides a substrate for the dual-pathway AVN conduction. We observed heterogeneity of expression of three isoforms of connexins: Cx43, Cx45, and Cx40. We identified the site of origin of junctional rhythm at the posterior extension of the AV node in 79% (n = 14) of the studied hearts. This structure was similar to the compact AV node as determined by morphologic and molecular investigations. In particular, both the posterior extension and the compact node express the pacemaking channel HCN4 (responsible for the I(F) current) and neurofilament 160. In the rabbit heart, AV junction conduction, reentrant arrhythmia, and spontaneous rhythm are governed by heterogeneity of expression of several isoforms of gap junctions and ion channels. Uniform neurofilament expression suggests that AV nodal posterior extensions are an integral part of the cardiac pacemaking and conduction system. On the other hand, differential expression of Cx isoforms in this region provides an explanation of longitudinal dissociation, dual-pathway electrophysiology, and AV nodal reentrant arrhythmogenesis.     

Disruption of RHOA-ROCK Signaling Results in Atrioventricular Block and Disturbed Development of the Putative Atrioventricular Node

The RHOA-ROCK signaling pathway is involved in numerous developmental processes, including cell proliferation, differentiation and migration. RHOA is expressed in the atrioventricular node (AVN) and altered expression of RHOA results in atrioventricular (AV) conduction disorders in mice. The current study aims to detect functional AVN disorders after disturbing RHOA-ROCK signaling in chicken embryos. RHOA-ROCK signaling was inhibited chemically by using the Rho-kinase inhibitor compound Y-27632 in avian embryos (20 experimental and 29 control embryos). Morphological examination of control embryos show a myocardial sinus venosus to atrioventricular canal continuity, contributing to the transitional zone of the AVN. ROCK inhibited embryos revealed lateralization and diminished myocardial sinus venosus to atrioventricular canal continuity and at the severe end of the phenotype hypoplasia of the AVN region. Ex ovo micro-electrode recordings showed an AV conduction delay in all treated embryos as well as cases with first, second (Wenkebach and Mobitz type) and third-degree AV block which could be explained by the spectrum of severity of the morphological phenotype. Laser capture microdissection and subsequent qPCR of tissue collected from this region revealed disturbed expression of HCN1, ISL1, and SHOX2. We conclude that RHOA-ROCK signaling is essential for normal morphological development of the myocardial continuity between the sinus venosus and AVN, contributing to the transitional zone, and possibly the compact AVN region. Disturbing the RHOA-ROCK signaling pathway results in AV conduction disturbances including AV block. The RHOA-ROCK inhibition model can be used to further study the pathophysiology and therapeutic strategies for AV block. Anat Rec, 302:83–92, 2019. © 2018 Wiley Periodicals, Inc.     

Treatment of supraventricular tachycardia due to atrioventricular nodal reentry, by radiofrequency catheter ablation of slow-pathway conduction.

BACKGROUND. Atrioventricular nodal reentrant tachycardia (AVNRT), the most common form of supraventricular tachycardia, results from conduction through a reentrant circuit comprising fast and slow atrioventricular nodal pathways. Antiarrhythmic-drug therapy is not consistently successful in controlling this rhythm disturbance. Catheter ablation of the fast pathway with radiofrequency current eliminates AVNRT, but it can produce heart block. We hypothesized that catheter ablation of the site of insertion of the slow pathway into the atrium would eliminate AVNRT while leaving normal (fast-pathway) atrioventricular nodal conduction intact. METHODS AND RESULTS. Eighty patients with symptomatic AVNRT were studied. Retrograde slow-pathway conduction (in which the earliest retrograde atrial potential was recorded at the posterior septum, close to the coronary sinus) was present in 33 patients. The retrograde atrial potential was preceded by a potential consistent with activation of the atrial end of the slow pathway (ASP). In 46 of the 47 patients without retrograde slow-pathway conduction, a potential with the same characteristics as the ASP potential was recorded during sinus rhythm. Radiofrequency current delivered through a catheter to the ASP site (in the posteroseptal right atrium or coronary sinus) abolished or modified slow-pathway conduction in 78 patients, eliminating AVNRT without affecting normal atrioventricular nodal conduction. In the single patient without ASP, the application of radiofrequency current to the proximal coronary sinus ablated the fast pathway and AVNRT. Atrioventricular block occurred in one patient (1.3 percent) with left bundle-branch block, after inadvertent ablation of the right bundle branch. AVNRT has not recurred in any patient during a mean (+/- SD) follow-up of 15.5 +/- 11.3 months. Electrophysiologic study 4.3 +/- 3.3 months after ablation in 32 patients demonstrated normal atrioventricular nodal conduction without AVNRT. CONCLUSIONS. Catheter ablation of the atrial end of the slow pathway using radiofrequency current, guided by ASP potentials, can eliminate AVNRT with very little risk of atrioventricular block.     

成人心二尖瓣的形态学研究

结合尸体断面解剖方法研究了36例成人心的二尖瓣，结果如下：1．在房室隔既有二尖瓣前叶的附着，也有二尖瓣后叶的附着，2．二尖瓣前叶组成左室流出道的后壁，前叶光滑部呈冠状位，向上续于主动脉下幕，从左室流出道观察，相续处没有区分标志，章讨论了这些结果在心导管插管和房室结定位研究中的意义。     

Factors of the successful radiofrequency catheter ablation to the slow pathway in patients with uncommon atrioventricular nodal reentrant tachycardia

We studied the clinical features and factors of successful catheter ablation for common and uncommon atrioventricular nodal reentrant tachycardia(AVNRT). The study population consisted of 41 consecutive patients, 33 with common type AVNRT (16 males mean age of 57.8 years), and 8 patients with uncommon type AVNRT (4 males, mean age of 57.1 years). In all patients with common type AVNRT, the earliest atrial activation during tachycardia was recorded at the His bundle region. The effective ablation sites were located in the medial septal area and all cases were successfully ablated without complication. In patients with uncommon type AVNRT, dual pathway was observed in 5 patients(63%) and triple pathway in 3 patients(38%). The earliest atrial activation during tachycardias was recorded at the ostium of the coronary sinus. Radiofrequency ablation therapy was performed during sinus rhythm in 5 patients, and during tachycardia in 3 others. The effective ablation sites were located at the posterior septal area around the coronary sinus ostium. All cases were successfully ablated without any major complication, but one case had second-grade atrioventricular block after ablation. There were no significant differences between the common and uncommon type AVNRT cases with regard to the therapeutic success rate, the mean application number or the total energy applied. However, the successful ablation sites were different between the two groups. We concluded that radiofrequency catheter ablation would be effective in patients with both common and uncommon types AVNRT. Selective ablation at the site of the retrograde slow pathway exit was the most important factor for successful catheter ablation for uncommon type AVNRT. However, it should be performed only after careful analysis, taking into account the complex mechanism of uncommon type AVNRT.     

房室交界区三角的观察和测量

在110例人心(成人70,儿童40)上,观察了由冠状窦口、Todaro腱及三尖瓣隔瓣附着缘围成的房室交界区三角,对上述各边界及室间隔膜部进行了测量。三角的三个角各有不同结构占据,前上角为房室结,顶角有冠状窦和心最小静脉开口,后下角深面为右冠状动脉“U”形袢。就上述特点结合临床进行了讨论。