心房颤动的发生机制

尽管诊断和研究技术不断发展,仍不能直接显示临床心律失常的机制。心房颤动（房颤）的发生有多种观点和假说,支持和否认每一种学说的证据是间接的［１～５］。对房颤的发生机制认识依旧是开放的,不应认为已有定论。　　１．心脏协调中心失常学说　　最初认为心脏各部协调一致的活动依赖于间隔协调中心（ｃｏｏｒｄｉｎａｔｏｒｃｅｎｔｅｒ）的控制。协调中心功能失常导致心肌活动不协调和心脏颤动。Ｋｒｏ－ｎｅｃｋｅｒ依据此学说用穿刺间隔的方法破坏协调中心,制造了房颤的模型。但Ｐｏｒｔｅｒ与ＭｃＷｉｌｌｉｏｎ观察到与心脏间隔…     

心脏自主神经作用于心房颤动的研究进展

心房颤动（房颤）是临床上最常见的心律失常之一。心脏自主神经在房颤的发生和维持中扮演了十分重要的角色。心脏内在和外在自主神经都对心脏节律和功能的调节具有重要意义,异常的自主神经激活可以导致房颤的发生。因此,在房颤研究中,自主神经调控已成为治疗房颤的研究热点。目前,较常用的心脏自主神经调控方法主要包括：去交感神经化,刺激迷走神经、消融心脏神经节从等。本文主要就心脏自主神经影响房颤的作用机制及心脏自主神经调控方法加以综述。     

心房颤动的再认识(四)

1心脏术后心房颤动(房颤) 房颤是心脏手术后最常见的并发症,房颤发生率因检出的方法和入选患者不同而异.在12项大的临床调查中报告,37 112例心脏术后患者,其中88.6%接受的是单纯冠状动脉搭桥(CABG)手术,术后房颤总的发生率为25.6%(15.4%～36.7%),CABG术后发生率为11%～40%.进行瓣膜手术或CABG和瓣膜联合手术者,术后房颤的发生率更高.心脏术后发生房颤时常伴有血流动力学不稳定,需要正性肌力药物、IABP等支持.血栓栓塞的发生率为1%～6%,发生后死亡率高(13%～41%).心脏术后发生房颤使患者的住院时间延长,术后并发症增加,中风发生率、院内死亡率和长期死亡率都增加,住院费用也会增加.因此,积极预防心脏术后房颤的发生,可以缩短住院时间,减少住院费用.     

自主神经系统与心房颤动研究新进展

心脏受交感神经和副交感神经的双重支配,其互相作用共同调节心脏。交感神经通过释放去甲肾上腺素、改变儿茶酚胺水平、影响离子电流等诱导心房颤动(简称房颤)发生,而副交感神经通过释放乙酰胆碱、改变肺静脉的电生理特征等诱导房颤发生,多数情况是两者交互作用或作用不平衡时诱导房颤发生。针对自主神经诱发房颤发生的干预措施有:①神经节消融;②脊髓刺激;③肾去交感神经;④耳屏刺激,这些措施均能起到降低房颤发生的作用。     

非传统抗心律失常药物在心房颤动治疗中的应用

心房颤动(房颤)是最常见的心律失常,在60岁以上的老年人中房颤的发病率达5%以上[1];中国人群中患房颤的人数有一千多万.房颤患者的死亡率比正常人高出两倍以上[2].房颤的发病机制目前尚不甚清楚,公认的是肺静脉起源学说及多子波学说;但神经内分泌,代谢及炎症等多因素都能导致心房重构,从而促使房颤的发生.     

干预心脏外在神经对心房颤动的影响

目前有多种方法可调节自主神经与心脏之间的复杂联系,然而不同的方法可能对心房颤动(简称房颤)有着不同的影响。研究证实,迷走神经刺激对房颤的影响呈强度依赖性,高强度刺激诱发房颤的发生,而低强度刺激可有效抑制心房重构,从而抑制房颤的发生。脊神经刺激和低强度颈动脉窦刺激均可抑制心脏内在神经,通过调节心脏内、外神经活性达到抑制房颤的作用。星状神经节消融与阻滞可逆转心房电重构并同时降低房颤发生率。肾去交感神经不仅抑制心房结构重构和电重构,而且降低局部甚至全身交感神经活性,减少房颤诱发并缩短房颤持续时间。正中神经刺激可抑制心房电重构与炎性因子水平,可能通过胆碱能抗炎通路发挥抗房颤效应。     

老年人心房颤动导管射频消融并发心脏压塞的临床分析

目的 探讨年龄与房颤导管消融并发心脏压塞之间的关系.方法 回顾性收集2013年1月至2016年12月在北京安贞医院行首次房颤导管射频消融术的患者,收集其围术期临床资料,分为老年组(≥60岁)和非老年组(＜60岁),利用回归模型分析老年与房颤消融心脏压塞发生的关系.结果 本研究共纳入患者5 313例,发生心脏压塞41例(...     

心房颤动的现代观点(6)心房颤动与心脏起搏

近年来心脏起搏技术的发展也表现在对心房颤动(房颤)的预防和治疗方面,包括采用单部位心房起搏,双心房(左、右)起搏,双部位(右心房的不同部位)起搏及不同工作程序等方法。传统的观点认为房颤是由心房内持续性折返激动引起。1920年Lewis提出了折返激动是房颤的发生机制。1959年Moe在计算机程控刺激实验的基础上提出了“多个小折返环”学说。1977年Allesie在兔的急性房颤模型中标测到多个直径小于1cm的小折返环,并提出核心折返环的概念,认为环中心组织可自动形成一个功能性传导屏障,不需特定的解剖结构就可以发生折返。1981年Hoffman提出了…     

心房颤动中心脏自主神经评价手段的研究进展

心脏受自主神经支配,自主神经系统包括心脏外在自主神经和固有自主神经系统,两者均包含交感成分和副交感成分,在心房颤动(房颤)的发生发展中均起重要作用。本文通过回顾文献,总结近年来用于评价心脏自主神经的手段,其中一些方法已经用来预测房颤的产生和发展,未来也可以通过这些方法进一步研究房颤的发病机制。     

自主神经系统在心房颤动中的作用和联系

心房颤动（房颤）在临床上极为常见,目前心房颤动的机制尚未阐明,其中自主神经系统在房颤的发生、维持、终止和决定室性心律上是一个潜在的强大的调节因素。存在于中枢、神经节、外周组织、细胞和亚细胞水平的交感和副交感系统的复杂相互作用都能够改变心脏的传导性和不应期,较为重要的是分布于心脏的自主神经的调节作用能引起心房节律的改变以及影响触发活动的产生和类型,所有这些变化都能引发和维持房颤。本文就心脏自主神经系统在房颤发生发展过程中的可能的作用机制及相互联系作一综述,为基础研究和临床实践中对房颤的机制研究和治疗提供参考依据和理论基础。     

Cryoballoon pulmonary vein isolation temporarily modulates the intrinsic cardiac autonomic nervous system

Purpose  

Modulation of the intrinsic cardiac autonomic nervous system (ICANS) has been described to occur during radiofrequency pulmonary vein (PV) isolation for paroxysmal atrial fibrillation (AF) and has been controversially proposed to increase clinical success. Energy source used for PV isolation might influence ICANS modulation. The effect of balloon-delivered cryoenergy on the ICANS is unknown. We conducted a study investigating acute periprocedural effect on ICAN as well as changes in heart rate variability (HRV) for standard deviation of normal-to-normal intervals (SDNN) and triangular index (TI) as surrogates for ICANS modulation after cryoballoon PV isolation.     

A Remodelação do Sistema Nervoso Autônomo Cardíaco pode Desempenhar um Papel na Fibrilação Atrial: Um Estudo do Sistema Nervoso Autônomo e Receptores Miocárdicos

BackgroundThe primary factors that originate and perpetuate atrial fibrillation (AF) are electrical and anatomical substrate alterations. However, the central mechanisms governing AF perpetuation have not been elucidated yet, which is reflected on the modest results of the treatment in patients with long persistent AF.ObjectiveTo evaluate if human intrinsic cardiac autonomic nervous system (ICANS) remodeling, including nervous system fibers and muscarinic and β-adrenergic receptors, play a role in permanent AF.MethodsHeart necropsy samples from thirteen patients with heart disease and permanent AF and thirteen controls without AF were used. By using immunoperoxidase and histomorphometry quantification, we identified the following: the density of all fibers of the ICANS, sympathetic and parasympathetic fibers; and the percentage of myocardium positive for β-adrenergic receptors 1, 2 and 3; G protein-coupled receptor kinase-5 (GRK-5); and muscarinic receptors M1 to M5. The results were compared using ANOVA and nested ANOVA and were adjusted according to the left atrium volume for all variables, and β-blocker use to evaluate the expression of β-receptors and GRK-5.ResultsThere was an overall increase in the density of fibers of the ICANS (p=0.006), especially in atrial sympathetic nerve fibers (p=0.017). Only M1 muscarinic receptors were increased (5.87 vs 2.35, p=0.032). For adrenergic receptors, the results were positive for increased expression of β-3 (37.41 vs 34.18, p=0.039) and GRK-5 (51.16 vs 47.66; p<0.001). β-blocker use had no impact on β-receptor expression.ConclusionIncreased ICANS innervation and remodeling receptor expression in regions prone to triggering AF may play a role in permanent AF.     

Severe persistent neurotoxicity associated with CAR T therapy in children

CD19-directed chimeric antigen receptor (CAR) T-cell therapy is an important therapy for relapsed or refractory acute lymphoblastic leukaemia, but its use carries the risk of immune effector cell-associated neurotoxicity syndrome (ICANS). In children, severe ICANS is almost universally reported in association with cytokine release syndrome and is reversible. We describe two cases of severe, intractable neurotoxicity following CAR T-cell therapy in children with pre-existing central nervous system (CNS) vulnerabilities. The cases were atypical in their delayed onset and independence from cytokine release syndrome and did not respond to standard therapies.     

心房颤动、结构重构与肾素-血管紧张素-醛固酮系统关系

心房颤动是临床上最常见的心律失常之一,有较高的发病率、致残率,严重影响患者的生活质量。但是关于心房颤动的发病机制至今并未完全明确,目前对其结构重构的发生机制研究较多,包括钙离子超载、心肌局部肾素-血管紧张素系统激活、基质金属蛋白酶改变、缝隙连接蛋白改变等。同时,针对导致心房颤动结构重构的可能机制,出现了一些新的预防和治疗心房颤动策略。现就心房颤动结构重构的发病机制研究及相应治疗进展做一综述。     

Low-level vagosympathetic nerve stimulation inhibits atrial fibrillation inducibility: direct evidence by neural recordings from intrinsic cardiac ganglia

Intrinsic Cardiac Ganglia Activity Inhibited by Low‐Level Vagal Stimulation . Introduction: We hypothesized that low‐level vagosympathetic stimulation (LL‐VNS) can suppress atrial fibrillation (AF) by inhibiting the activity of the intrinsic cardiac autonomic nervous system (ICANS). Methods and Results: Wire electrodes inserted into both vagosympathetic trunks allowed LL‐VNS at 10% or 50% below the voltage required to slow the sinus rate or atrioventricular conduction. Multielectrode catheters were attached to atria, atrial appendages and all pulmonary veins. Electrical stimulation at the anterior right and superior left ganglionated plexi (ARGP, SLGP) was used to simulate a hyperactive state of the ICANS. Effective refractory period (ERP) and window of vulnerability (WOV) for AF were determined at baseline and during ARGP+SLGP stimulation in the presence or absence of LL‐VNS. Neural activity was recorded from the ARGP or SLGP. ARGP+SLGP stimulation induced shortening of ERP, increase of ERP dispersion and increase of AF inducibility (WOV), all of which were suppressed by LL‐VNS (10% or 50% below threshold) at all tested sites. Sham LL‐VNS failed to induce these changes. The effects of LL‐VNS were mediated by inhibition of the ICANS, as evidenced by (1) LL‐VNS suppression of the ability of the ARGP stimulation to slow the sinus rate, (2) the frequency and amplitude of the neural activity recorded from the ARGP or SLGP was markedly suppressed by LL‐VNS, and (3) the spatial gradient of the ERP and WOV from the PV‐atrial junction toward the atrial appendage was eliminated by LL‐VNS. Conclusions: LL‐VNS suppressed AF inducibility by inhibiting the neural activity of major GP within the ICANS. (J Cardiovasc Electrophysiol, Vol. 22, pp. 455‐463)     

C-反应蛋白与心房颤动的关系

导管射频消融已成为治疗心房颤动的有效手段,具有较高的手术成功率,但对于部分患者仍存在复发现象。越来越多的证据表明炎症与心房颤动的发生发展有关,C-反应蛋白作为组织炎症的标志,具有较高的敏感性、精确性,可以作为炎症反应的监测指标。目前的研究表明,C-反应蛋白水平升高是心房颤动发生的独立预测因素,但C-反应蛋白与心房颤动复发是否有关尚无定论。为此,现对C-反应蛋白与心房颤动的关系的研究进展作一综述,为以后的研究提供参考。     

缝隙连接蛋白40和心房颤动

随着对心房颤动机制越来越深入的了解,缝隙连接蛋白在其中扮演的作用日益受到重视。缝隙连接蛋白中的连接蛋白40在心房颤动过程中数量、分布、及分子结构都发生了变化。连接蛋白40基因突变及多态性增加了心房颤动的易患性,尽管连接蛋白40在心房颤动发生和维持中的具体机制尚未完全阐明,但一些针对连接蛋白的药物应用于心律失常有较好的效果。现就连接蛋白40与心房颤动的关系进行综述。     

Molecular characterization of aspergillus fumigatus allergens

Aspergillus fumigatus (Af) is ubiquitous saprophytic fungus associated with a broad spectrum of diseases in humans. These diseases range from benign colonization of the lung to life threatening diseases such as allergic bronchopulmonary aspergillosis (ABPA) and invasive aspergillosis. Af is the etiologic agent identified in most of the Aspergillus related human diseases and is therefore of particular clinical importance. Af induced obstructive airway diseases may be due to transient exposure to fungal spores resulting in a T helper 2 response. The IgE mediated inflammatory reaction could be due to colonization of bronchial airway epithelium by Af. Early and precise diagnosis of Aspergillus induced respiratory allergy is essential for preventing irreversible lung damages. The major problems in the diagnosis of A. fumigatus induced diseases are due to the lack of standardized and well characterized fungal extracts. The advent of molecular cloning technology and the development of phage surface display technology for cloning genes have facilitated the isolation of more relevant recombinant allergens. Using these techniques, a panel of different Af allergens having distinct IgE binding with various groups of Af sensitized patients have been cloned and characterized. These allergens can be categorized functionally as secreted and cytoplasmic proteins. The distinct IgE binding property of these purified and well characterized recombinant Af allergens may be useful for the differential diagnosis of Af related pulmonary complications.     

控制心律或控制心率--心房颤动治疗的两种策略

心房颤动是成年人最常见的心律失常,恢复窦性心律并长期维持(控制心律)和允许心房颤动存在,仅控制心率在目标水平(控制心率)是治疗心房颤动的两种策略,就目前认识的药物治疗心房颤动的这两种策略以及前瞻性对照试验尚未解决的领域等问题作一简要综述。