Treatment of atrial flutter and rapid atrial tachycardia with transesophageal atrial pacing

Eight patients with atrial flutter (AF) and rapid atrial tachycardia (AT) (5 common AF, 1 uncommon AF and 2 AT) were treated with transesophageal atrial pacing (TEAP). In 5 patients no antiarrhythmic agent was used during this study, and in 3 patients procainamide was administrated intravenously. Conversion to sinus rhythm was successfully achieved in 7 patients (5 common AF and 2 AT). Two patients were converted to sinus rhythm immediately after pacing, and transient atrial fibrillation was induced before conversion to sinus rhythm in 5 patients. TEAP failed to terminate the arrhythmia in 1 patient with uncommon AF. Administration of procainamide reduced the atrial rate in 2 common AF and 1 AT, which were successfully converted to sinus rhythm by TEAP, but induced a rapid ventricular response in 2 patients, one of whom also developed hypotension before conversion. No significant complication due to TEAP was observed in this study. In conclusion, TEAP is a noninvasive method with fewer complications and has nearly the same high efficacy for converting AF and rapid AT to sinus rhythm as DC cardioversion or transvenous atrial pacing.     

心房重构在房颤中的作用

房颤的发病机制非常复杂,与心房的重构(包括电学重构、解剖重构和自主神经系统重构)密切相关.房颤可诱导离子通道蛋白表达和(或)功能异常,进而反馈性地促进心房功能性折返基质的形成,发生电学重构;循环往复的电学重构造成心房基质的改变,失活的心房肌细胞被纤维组织替代,心房逐渐纤维化,出现解剖重构;与此同时,心房广泛的纤维化进一步阻碍电冲动的传导,反过来加重电学重构;自主神经系统重构可通过正向反馈环机制促进房颤的维持和复发.早期治疗心房重构可延迟甚至预防房颤的发生和发展.     

心房粘液瘤对心房除极的影响

为探讨心房粘液瘤对心房激动过程的影响,对19例左心房粘液瘤和2例右心房粘液瘤的VCG高倍P环(1mV=360mm)进行测量,结果显示不同部位粘液瘤对心房激动的影响不同,VCGP环亦不同.左心房粘液瘤P环时限延长,除左心房肥大外,较容易判断出双侧心有肥大、房内传导阻滞.右心房粘液瘤P环时限正常,仅表现右心房肥大.VCG上放大的P环能比ECG上P波更敏感地反映出心房异常活动的电变化.     

经导管线性消融术对左心房功能影响的研究

目的评价左心房线性消融术对心房颤动（房颤）患者左心房功能的影响。方法选择30例Carto系统标测指导下行左心房线性消融术的阵发性房颤患者，应用超声心动图测定其消融术前1～3d、术后3个月静息时窦性心律下左心房容积指标、二尖瓣口A波速度峰值（VA）及左心房射血力，分析消融术前后左心房功能的变化。结果消融术后反应左心房辅泵功能的指标左心房射血力、VA、左心房主动排空容积、左心房主动排空分数、左心房总排空分数显著下降，反应左心房管道功能的左心房管道容积增加，反应左心房储存功能的指标左心房总排空容积、左心房最大容积无明显变化。结论Carto系统标测下左心房线性消融术后左心房辅泵功能下降，管道功能增强，而储存功能无显著改变。     

心房肌细胞凋亡及凋亡相关基因在房颤心房重构中的意义

目的 分析风湿性心脏病患者房颤发生与发展的特点，探讨心房肌细胞凋亡以及凋亡相关基因表达变化在房颤心房重构中的意义。 方法 统计分析瓣膜置换手术25例患者临床资料。根据心电图资料分为窦性心律组（10例）和房颤心律组（15例）；术中取右心房组织，行Masson染色及天狼猩红染色，计算胶原容积分数（CVF）评价心房纤维化情况；运用TUNEL染色，荧光显微镜下观察两组细胞凋亡差异；用RT-qPCR检测两组样本凋亡相关基因的表达。 结果 与窦律组比较，房颤组患者LADd和RADd显著增大（均P < 0.01），LVEF显著降低（P < 0.01）、CVF显著增大（P<0.05）、细胞凋亡率显著增高（P < 0.05）、TP53，BAX，Slug-SNAI2基因表达率显著增高（P < 0.05），而BCL-2，BPM4的表达显著降低（P < 0.05）。Pearson相关分析显示LADd、RADd、心房细胞凋亡率和CVF之间存在相关性。 结论 心房细胞的凋亡在心房重构纤维化形成过程中发挥重要作用，其机制与心肌细胞死亡后纤维组织代替性修复有关，调控心房肌细胞凋亡有望改善心房纤维化的形成。     

房颤心房纤维化相关研究的文献计量学分析

目的 分析近20年房颤心房纤维化相关领域的研究现状、热点及趋势。 方法 以Web of Science核心合集数据库为数据来源,利用可视化分析软件CiteSpace对近20年房颤心房纤维化相关研究进行可视化分析,探讨相关研究的作者、国家/机构分布、期刊分布状况以及对关键词进行分析。 结果 纳入1 468篇SCI文章,发文量最高的作者是Nattel S,引文量最高的是Burstein B。美国和中国为该领域研究的主要国家,美国犹他大学、约翰霍普金斯大学是房颤心房纤维化研究的重要机构,载文量最多的期刊是《Journal of cardiovascular electrophysiology》,被引频次最高的期刊是《Circulation》,主要的研究热点是①心力衰竭/心肌梗死并发心房颤动与心房纤维化研究;②心房纤维化评估在心房颤动导管消融/基质消融中的应用③炎症及氧化应激在房颤心房纤维化中的作用机制研究。研究的前沿方向主要有①关于房颤患者的患病率、复发率和死亡率的研究;②房颤患者中风的预防;③基于心肌成纤维细胞探讨房颤相关机制的研究;④房颤患者的管理;⑤通过延迟增强MRI评估心房组织纤维化程度。 结论 本研究为了解房颤心房纤维化相关研究提供了一个视角,为研究者识别潜在的合作者和合作机构、热点话题和研究前沿提供了有价值的信息。     

Simultaneous occurrence of atrial fibrillation and atrial flutter

INTRODUCTION: Early reports suggested that some patients with "atrial fibrillation/flutter" might have atrial fibrillation in one atrium and atrial flutter in the other. However, more recent conceptions of atrial fibrillation/flutter postulate that the pattern is due to a relatively organized (type I) form of atrial fibrillation. We report the occurrence and ECG manifestations of simultaneous atrial fibrillation and flutter in patients undergoing attempted catheter ablation of atrial flutter. METHODS AND RESULTS: In patients undergoing radiofrequency ablation for atrial flutter, an attempt was made to entrain atrial flutter by pacing in the right atrium. The arrhythmias observed occurred following attempts at entrainment, or spontaneously in one case. Twelve transient episodes of simultaneous atrial fibrillation and flutter were observed in five patients. The atrial fibrillation was localized to all or a portion of one atrium, during which the other atrium maintained atrial flutter. In each case, the surface 12-lead ECG reflected the right atrial activation pattern. No patients had interatrial or intra-atrial conduction block during sinus rhythm, suggesting functional intra-atrial block as a mechanism for simultaneous atrial fibrillation/flutter. CONCLUSION: In certain patients, the occurrence of transient, simultaneous atrial fibrillation and flutter is possible. In contrast to prior studies in which it was suggested that left atrial or septal activation determines P wave morphology, the results of the present study show that P wave morphology is determined by right atrial activation. Functional interatrial block appears to be a likely mechanism for this phenomenon.     

Pharmacological therapy of atrial fibrillation and atrial flutter

BACKGROUND: Despite the increasing availability of nonpharmacological treatment options for atrial fibrillation, drug therapy targeted at restoration and maintenance of sinus rhythm, or aimed at symptomatic ventricular rate control remains the mainstay of therapy for the majority of patients. METHOD: Available data suggest that these two treatment approaches yield similar responder rates with regard to symptomatic improvement. RESULTS: Detailed results from major prospective studies investigating the prognostic effects of different atrial fibrillation treatment modalities are expected to become available soon. At present, however, the choice of the primary treatment strategy, i.e. rate control or rhythm control, still remains upon the clinical decision and expertise of the treating physician. Cardioversion by means of external biphasic shock delivery has shown to effectively convert atrial fibrillation to sinus rhythm in more than 90% of patients. Pharmacological cardioversion, in contrast, has a far lower success rate and may be followed by severe complications mandating in-hospital administration with the majority of drug regimens. For the maintenance of sinus rhythm, the proarrhythmic side effects of Class I antiarrhythmic drugs currently limit their use to those patients without any structural heart disease. Clinical investigation of newer "pure" Class III drugs have shown to excite considerable prolongation of ventricular repolarization duration resulting in a significant risk for torsade-de-pointes tachycardia. Betablockers are beneficial in many clinical situations associated with the occurrence of atrial fibrillation, such as heart failure, arterial hypertension and coronary artery disease. These substances, however, do not seem to improve cardioversion rates and their effect in maintaining sinus rhythm is only moderate. Patients with structural heart disease in whom maintenance of sinus rhythm is strongly desired, therefore, are left to amiodarone therapy. The cardiac safety profile as well as the proven effectiveness are unsurpassed by any other available drug at present. This paper reviews major studies published during the last decade implementing recent guidelines regarding pharmacological rate control, cardioversion and maintenance of sinus rhythm and the approach towards patients suffering from paroxysmal atrial fibrillation.     

Suppression of atrial fibrillation by atrial pacing.

BACKGROUND: Atrial fibrillation (AF) is a common arrhythmia in patients with an implanted pacemaker, but the role of atrial pacing in preventing AF is still unclear. METHODS AND RESULTS: Sixty-six patients (67.8+/-12.1 years) were enrolled: 54 with sick sinus syndrome (SSS), 11 with atrioventricular blocks (AVB), and 1 with SSS and AVB. The prevalence of AF was investigated. In 22 patients with AF, the AF burden was estimated under "back-up pacing" (40-50 beats/min), then under "atrial pacing" (60-85 beats/min). The prevalence of AF in the SSS group tended to be higher than that in the AVB group (48.1% vs 18.2%, p=0.06). The AF burden in patients with a percentage of atrial pacing (% atrial pacing) <50% was significantly greater than that in patients with % atrial pacing >or=50% (12.5+/-21.1% vs 4.2+/-10.3%, p<0.05). AF disappeared immediately after "atrial pacing" in 4 patients (18.2%). In 9 patients (40.9%), the AF burden decreased gradually, and AF disappeared in 6 patients (27.3%) after 207.9+/-130.2 days. CONCLUSION: The prevalence of AF may be higher in patients with SSS than in those with AVB. Atrial pacing has a preventive effect on AF, and the effect of atrial pacing is not always immediate but is progressive in some patients.     

心房颤动与心房重构的最新进展

心房颤动（房颤,AF）是引起心血管发病和死亡的重要原因.房颤是常见的由一系列心脏疾病引起心房重构的终点事件,其本身也能引起心房重构从而促进心律失常的发展[1].随着人们对心房重构的机制及其在房颤进展中作用的逐渐认识,对离子通道调控机制和作用靶点的研究也有了较深入的发展.本文将重点综述这方面的进展.