多部位心脏起搏

ｌ 概念 多部位心脏起搏是指在心房和（或）心室内存在多个部位或位点的起搏技术。是晚近面世的一种新的起搏技术。其目的是通过调整起搏部位来改变心脏除极的顺序和路径,恢复心房或心空的电机械同步性,以便能获取更好的抗心律失常效果和血流动力学效果。２ 病理生理学基础 心房肌纤维无论是解剖特性还是电生理特性均不同于心室肌。在心房内存在多个电传导的天然屏障,如上、下腔静脉,肺静脉,房室瓣,冠状静脉窦开口等。心房内压力低,很容易被动扩张和增大;心房肌的血液供应相对少,容易发生生理性或病理性退行性变。除上述解剖上的特…     

心房颤动的心电现象及其识别

心房颤动（房颤）多见于有心脏病者，但约20％的永久性房颤和45％的发作性房颤患者没有可被确认的危险因素，即孤立性房颤^[1]。心房解剖结构特点和电生理特性是房颤的易发基础，与心房易损性、兴奋波波长、心肌非均一性和各向异性等因素密切相判^[2]。房颤的病因和发病机制复杂，电生理和心电图表现多样，需要认真研究和识别。     

心房颤动的心房重构

心房颤动心房重构是指房颤后心房肌发生电生理、生化、解剖结构和收缩功能上改变(即电重构、生化重构、收缩功能重构、解剖重构),也称为心房心肌病。心房重构在房颤的发生、复发及维持方面起着明显作用,具有重要的临床意义。以下是国内外近几年来的一些研究结果。     

心腔内超声在房性心律失常介入治疗中的应用

随着心脏电生理疾病介入治疗方法学的迅速发展,房性心律失常的射频消融治疗已成为心脏电生理治疗的主要手段.近二十年来,射频导管消融术引导方式由X线透视和心内电标测发展到非接触心内膜激动标测系统(EnSite 3000,Carto/XP系统),该系统可以根据心肌电活动信息计算并重建心腔心内膜的三维立体图形,此类技术的主要局限在于不能获得实时同步的心脏解剖和功能图像,其所标测的电位变化和分布很难准确与具体的心脏解剖结构、空间位置相关联.     

冠状静脉与心脏介入

心脏的血液供应来自左、右冠状动脉,静脉血经冠状静脉的深、浅静脉系统回流入心房和心室.近年来随着心脏介入技术的广泛应用,冠状静脉成为心脏介入常用的导管操作、放置部位和手术靶点.随着临床应用的日益增多,冠状静脉的研究逐渐深入.笔者就冠状静脉解剖结构、生理特点、临床检测手段以及与心脏介入的关系作一综述.     

风湿性心脏病慢性房颤心房扩大与心房电生理的相关性研究

目的：探讨风湿性心脏病慢性房颤左房内径大小对心房电生理特性的影响。方法：选择风湿性心脏病慢性房颤患者16例，术前采用超声心动图测量左心房内径，采用心外膜标测技术测量心房有效不应期（AERP）和波长指数（WLI），并与左房内径行相关性分析。结果：慢性房颤患者左房内径和右房压力明显高于窦性心律患者（P〈0．05），左房内径与AERP和WLI呈负相关（r=-0．882和-0．745）。结论：风心病慢性房颤左心房扩张影响心房的电生理特性，提示左心房的扩张引起心房结构重构，并影响心房的电生理重构而导致房颤的发生和维持。     

心房功能的解剖M型超声研究

心房功能对心力衰竭的影响已被以往的研究所证实，然而过去的研究多局限于从心电生理角度，极少从功能运动方面进行研究，全方位解剖M型超声的问世使我们有可能对心房的功能作一些研究，以帮助了解心房在整个心脏泵血功能中发挥的作用，最近，我们用全方位解剖M型技术对正常人左、右心房和房间隔的运动进行了一些初步探讨，旨在分析正常左、右心房及房间隔功能特点，现报告如下：     

经食道心房起搏抢救心脏骤停成功1例

我们在常规心肺复苏（CPR）方法基础上，使用心脏电生理刺激仪经食道心房起搏抢救呼吸、心脏停止1例获得成功，现报道如下。     

经食道心房调搏在儿科的临床应用

一、概述心脏电生理检查是研究、诊断和治疗心律失常和心脏疾病重要手段之一,既往均采用侵入性心内检查法。国外于1975年首次在儿科开展心内电生理研究及应用,为有创性方法,这在儿科应用特别受限制。食道前面与左心房后内侧紧贴,因此可经食道记录心电图或电刺激心房。1957年 Shafiroff 和 Linder 首先报告采用食道电极进行心房调搏。1973年 Montoyo 氏首先应用食道心房调搏治疗心动过速。1980年 Gallagher     

建立反映心脏内部各腔室结构的数字化三维模型

背景：心脏内部各腔室精细结构的数字化三维模型,不仅能够加强对心脏生理的认识,还能为心脏电生理仿真与心内膜电生理标测导航的研究提供重要的基础医学数据。目的：建立符合心腔实际解剖结构的三维数据,建立反映心脏内部各腔室结构的数字化三维模型。方法：在 MATLAB软件环境下完成图像分割,首先对医学人体断层数据集中心脏切片图像进行自动配准,再运用聚类法根据图像的颜色特征对图像中各组织与成分进行分类,随后经区域生长法处理实现心腔及相关连通区域的图像分割与提取。所得图像导入专用医学图像处理软件,完成心腔三维模型重建。结果和结论：所提出的方法能够重建出较为精细的心腔结构三维模型。此模型中左右心房、心室结构明晰,能清楚地观察到主动脉、上腔静脉等血管,三尖瓣与二尖瓣等微细结构也有所体现。结果说明,重建的三维模型能够准确地反映出人体心腔解剖学结构特征,为心脏电生理方面的仿真和标测研究提供基础的医学数据支持。     

Cardiac CT for Pre-Procedural Electrophysiologic Study Planning

Therapeutic electrophysiology procedures have rapidly evolved to help improve the quality of life in patients with heart rhythm disturbances. Cardiac CT angiography is a robust, high-resolution imaging tool that is commonly utilized for electrophysiology procedural planning and to improve intraprocedural efficiency. While cardiac CT is most often used to support radiofrequency ablation for atrial fibrillation, it also helps in assessing cardiac veins for cardiac resynchronization therapy, the left atrial appendage for thrombus, and post-procedural complications such as pulmonary vein stenosis. In this article, we will discuss the utility of cardiac CT for electrophysiology procedural related indications.     

Accessory appendages of the left atrium as seen during 64-slice coronary CT angiography

PURPOSE: To document the frequency and variations in number and anatomical shape of accessory appendages of the left atrium as seen on 64-slice cardiac CT. METHODS AND MATERIALS: Retrospective review of the anatomy of the left atrium as depicted by cardiac CT using the acquisition protocol designed for coronary CT Angiography and performed in 166 patients over a 6-month period with a 64-slice ECG-gated CT scanner (Siemens Medical Solutions). The local IRB provided a waiver of informed consent for this retrospective study. Structures less than 5 mm in shape were excluded, as well as large accessory pulmonary veins. RESULTS: Seventeen (17) of 166 patients (10%) had 18 accessory left atrial appendages (only one patient had two). Fifteen (15) accessory appendages were located along the right upper atrial wall and measured 0.9 x 0.6 x 0.5 cm(3) +/- 0.2 x 0.2 x 0.1 (Type 1). Three (3) were located along the left lower atrial wall, and were larger (0.9-2.5 cm cross-section) (Type 2). The right upper accessory appendages were mostly shaped like small diverticuli and the left lower ones were shaped like flat cauliflower expansions. CONCLUSIONS: Accessory left atrial appendages were visualized in 10% of 166 patients during 64-slice coronary CT angiography.     

Electrophysiological properties of the left atrium evaluated by coronary sinus pacing in patients with atrial fibrillation

Repetitive atrial firing (RAF), marked fragmentation of atrial activity (FAA), and interatrial conduction delay (CD) have been shown to be electrophysiological features of the atrium in patients with atrial fibrillation (AF). Moreover, it has been observed that atrial extrastimuli are more likely to induce AF when delivered from the right atrial appendage (RAA) than from the distal coronary sinus (CSd). We examined the electrophysiological properties of the atrial muscle by CS and RAA stimulation in patients with paroxysmal AF. Patients were divided into two groups: group I, consisting of 18 patients with clinical paroxysmal AF; and group II, consisting of 22 patients with various cardiac arrhythmias in which the substrate does not exist in the atrium. In group I, the following values of electrophysiological parameters of the atrium indicated that AF was more likely to be induced during RAA pacing than CSd pacing: atrial effective refractory period (RAA vs CSd: 201 +/- 28 ms vs 240 +/- 35 ms, P < 0.001), RAF zone (16 +/- 25 ms vs 0 +/- 0 ms, P < 0.03), FAA zone (38 +/- 37 ms vs 5 +/- 19 ms, P < 0.01), maximum interatrial conduction time (144 +/- 19 ms vs 93 +/- 19 ms, P < 0.0001) and CD zone (53 +/- 21 ms vs 9 +/- 18 ms, P < 0.0001). The values of the electrophysiological parameters of the atrium evaluated by CSd pacing in group I patients were not significantly different from those in group II patients. In conclusion, when coronary sinus stimulation is performed, electrophysiological properties of the atrium in patients with AF show a significant decrease in atrial vulnerability compared to stimulation from RAA and also show similar values to those in patients without AF. It might be suggested that the left posterior or posterolateral atrium is electrophysiologically stable even in patients with paroxysmal AF.     

Structural and electrophysiological characteristics of the heart function during paroxysmal atrial fibrillation

AIM: To examine structural and electrophysiological predictors of the onset and establishment as chronic of cardiac fibrillation (CF). MATERIAL AND METHODS: Echocardiography, transesophageal electrophysiological examination of the heart were performed in 420 cases of paroxysmal cardiac fibrillation (PCF). They were diagnosed as having new-onset (n = 68), rare (n = 92) and frequent (n = 260) PCF. RESULTS: Compared to healthy subjects, PCE patients had larger size of the left atrium (LA), higher atrium/ventricle value, lower frequency threshold of arrhythmia induction, decreased left atrial effective refractory period, longer induced paroxysm and maximal atrial response. CF chronicity can be predicted with the frequency threshold of arrhythmia induction under 300 imp/min, left atrial effective refractory period under 220 ms, left atrial size over 42 mm, induction of persistent PCF. CONCLUSION: A significant correlation was found between left atrial size and electrophysiological parameters of the heart characterizing arrhythmogenic "readiness" of the atria. This suggests a provoking role of left atrial dilatation in PCF.     

超声心动图技术评价左房形态及功能的研究进展

随着超声心动图技术的不断发展,越来越多新技术应用于左房研究中。左房主要有3个功能,即储存、管道和辅泵功能,左房功能在维持左室充盈方面发挥作用,左房形态及功能评价在预测心血管事件危险性、病死率及预后方面有重要价值。目前可通过多种超声心动图技术对左房进行评估,为临床心血管疾病的诊断、治疗及预后提供可靠依据。     

Ultrafast CT and the cardiovascular system

Ultrafast computed tomography (CT) is a new imaging technique that relies on electron beam technology. Its rapid image acquisition speeds make it ideal for evaluating the cardiovascular system. The high-resolution, flow, and cine-modes are unique and provide complimentary information about cardiovascular anatomy, function, and flow dynamics. Ultrafast CT can provide quantitative measurements of cardiac output, ejection fraction, ventricular volumes, and ventricular mass as well as evaluation of segmental cardiac function. This technique can be used to assess coronary artery bypass graft patency as well as to screen for coronary artery calcium. Intracardiac thrombus or tumor, valvular disease, and disorders of the pericardium can be evaluated and characterized using ultrafast CT. The diagnosis of congenital lesions of the heart and great vessels is facilitated by this imaging modality, which can help determine complex anatomic abnormalities and quantitate shunt lesions. Acquired lesions of the great vessels, such as aortic dissection and aneurysm, can be diagnosed by ultrafast CT, which can also be used for serial examination and conservative management.     

Atresia of the coronary sinus in patients with supraventricular tachycardia

Background: Atresia of the coronary sinus (CS) ostium with retrograde drainage of the cardiac veins via the persistent left superior vena cava (PLSVC) is a rare abnormality and only a few case reports in association with electrophysiological studies have been reported.
Methods: During standard electrophysiological study in three patients with a focal left atrial tachycardia, atrial fibrillation and common type right atrial flutter, the CS could not be cannulated despite several attempts. Assuming an occluded CS ostium we advanced a multipurpose catheter via the right atrium and the right superior vena cava in a PLSVC and performed CS angiography.
Results: CS angiography showed that the CS was occluded in all 3 patients and the PLSVC was used as a drainage route to the superior vena cava. After retrograde placement of a 2.5 Fr nonsteerable diagnostic catheter via the PLSVC in the CS, the intracardiac CS electrogram was recorded. Successful ablation could be performed in all three cases.
Conclusions: The cases highlight the possibility that failure to access the CS during electrophysiological studies may be related to this anomaly and that retrograde cannulation via PLSVC enables the CS access and acquisition of its electrograms.     

老年左房前壁自发性瘢痕相关心房扑动的电生理特征及分析

目的:探讨老年患者左房前壁自发性瘢痕相关心房扑动(房扑)的电生理特征及消融预后。方法:选择2018年1月至2020年1月复旦大学附属闵行医院收治的左房前壁自发性瘢痕相关的老年房扑患者5例,行电生理检查及三维电解剖指导下的射频消融术,平均年龄(76.6±10.5)岁,均为持续性房扑。术中通过激动标测、拖带标测以及电压标测等技术,确定房扑的诊断、机制、关键峡部及其与左房前壁自发瘢痕和低电压区的关系。结果:5例患者左房扩大,其中3例升主动脉内径增宽。5例患者均在左房前壁标测到低电压区和瘢痕区,多位于左房前壁靠近升主动脉压迹的部位。房扑均为折返性,关键峡部位于局部低电压区,消融后均成功终止房扑。其中1例因左房内径较大,同时行环肺静脉电隔离;1例复发,行二次消融。平均随访(15.6±4.2)个月后无复发。结论:左房前壁自发性瘢痕是部分老年患者左房房扑的发病基质,房扑的机制为折返性;左房内径扩大、升主动脉内径增宽可能与左房前壁瘢痕区和低电压区的形成相关。     

CT evaluation of left atrial pulmonary venous anatomy

Multidetector CT (MDCT) visualization of the left atrial pulmonary venous anatomy is becoming increasingly requested prior to radiofrequencey catheter ablation (RFCA) procedures for refractory cardiac arrhythmias. MDCT imaging can define left atrial anatomy including atrial size and venous attachments as well identify complications such as stenoses, dissections or perforations. Proper understanding enables the cardiac imager to be knowledgeable so as to obtain the specific information needed for the interventional cardiologist. This paper reviews the left atrial venous anatomy, the clinical aspects of refractory atrial fibrillation, MDCT imaging protocols, procedural aspects of the ablation, and complications should they arise.     

Intracardiac echocardiography (9 MHz) in humans: methods, imaging views and clinical utility

A new low-frequency (9 MHz, 9 Fr) catheter-based ultrasound (US) transducer has been designed that allows greater depth of cardiac imaging. To demonstrate the imaging capability and clinical utility, intracardiac echocardiography (ICE) using this lower frequency catheter was performed in 56 patients undergoing invasive electrophysiological procedures. Cardiac imaging and monitoring were performed with the catheter transducer placed in the superior vena cava (SVC), right atrium (RA) and/or right ventricle (RV). In all patients, ICE identified distinct endocardial structures with excellent resolution and detail, including the crista terminalis, RA appendage, caval and coronary sinus orifices, fossa ovalis, pulmonary vein orifices, ascending aorta and its root, pulmonary artery, RV and all cardiac valves. The left atrium and ventricle were imaged with the transducer at the limbus fossa ovalis of the interatrial septum and in the RV, respectively. ICE was important in identifying known or unanticipated aberrant anatomy in 11 patients (variant Eustachian valve, atrial septal aneurysm and defect, lipomatous hypertrophy, Ebstein's anomaly, ventricular septal defect, tetralogy of Fallot, transposition of the great arteries, disrupted chordae tendinae and pericardial effusion) or in detecting procedure-related abnormalities (narrowing of SVC-RA junction orifice or pulmonary venous lumen, atrial thrombus, interatrial communication). In patients with inappropriate sinus tachycardia, ICE was the primary ablation catheter-guidance technique for sinus node modification. With ICE monitoring, the evolution of lesion morphology with the three imaging features including swelling, dimpling and crater formation was observed. In all patients, ICE was contributory to the mapping and ablation process by guiding catheters to anatomically distinct sites and/or assessing stability of the electrode-endocardial contact. ICE was also used to successfully guide atrial septal puncture (n = 9) or RA basket catheter placement (n = 4). Thus, ICE with a new 9-MHz catheter-based transducer has better imaging capability with a greater depth. Normal and abnormal cardiac anatomy can be readily identified. ICE proved useful during electrophysiological mapping and ablation procedures for guiding interatrial septal puncture, assessing placement and contact of mapping and ablation catheters, monitoring ablation lesion morphological changes, and instantly diagnosing cardiac complications.