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.     

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。     

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.     

心房颤动与心房纤维化机制的研究

心房颤动(AF)是临床上常见的心律失常,65岁以上的老年人将近5%患有AF,心房纤维化为AF的发生和维持提供病理基础.研究显示,心房间质纤维化随着年龄增长而增加,在AF患者、衰老的动物模型以及充血性心力衰竭(CHF)患者中,同样观察到心肌间质纤维化的现象.在CHF的动物模型和选择性心房纤维化的转基因小鼠模型研究中发现,...     

植入型心房除颤器治疗心房颤动的临床应用

目的 评估入型心房除颤器（ｉｍｐｌａｎｔａｂｌｅ ａｔｒｉａｌ ｄｅｆｉｂｒｉｌｌａｔｏｒ，ＩＡＤ）治疗阵发性和持续性心房颤动（房颤）患者的有效性和安全性。方法 １１例患者（８例阵发性房颤，３例持续性房颤）安装了ＩＡＤ，型吨Ｍｅｔｒｉｘ＾ＴＭ３０００和Ｍｅｔｒｉｘ＾ＴＭ３０２０。所有的患者在室功能正常，４５％存在高血压等基础心脏病。ＩＡＤ在识别房颤和心室同步化后，通过右房－冠状静脉窦电流路线，发放     

Effect of left atrial circumferential ablation for atrial fibrillation on left atrial transport function

BACKGROUND: The effects of left atrial (LA) circumferential ablation on LA function in patients with atrial fibrillation (AF) have not been well described. OBJECTIVES: The purpose of this study was to determine the effect of LA circumferential ablation on LA function. METHODS: Gated, multiphase, dynamic contrast-enhanced computed tomographic (CT) scans of the chest with three-dimensional reconstructions of the heart were used to calculate the LA ejection fraction (EF) in 36 patients with paroxysmal (n = 27) or chronic (n = 9) AF (mean age 55 +/- 11 years) and in 10 control subjects with no history of AF. Because CT scans had to be acquired during sinus rhythm, a CT scan was available both before and after (mean 5 +/- 1 months) LA circumferential ablation (LACA) in only 10 patients. A single CT scan was acquired in 8 patients before and in 18 patients after LACA ablation. Radiofrequency catheter ablation was performed using an 8-mm-tip catheter to encircle the pulmonary veins, with additional lines along the mitral isthmus and the roof. RESULTS: In patients with paroxysmal AF, LA EF was lower after than before LACA (21% +/- 8% vs 32 +/- 13%, P = .003). LA EF after LA catheter ablation was similar among patients with paroxysmal AF and those with chronic AF (21% +/- 8% vs 23 +/- 13%, P = .7). However, LA EF after LA catheter ablation was lower in all patients with AF than in control subjects (21% +/- 10% vs 47% +/- 5%, P < .001). CONCLUSION: During medium-term follow-up, restoration of sinus rhythm by LACA results in partial return of LA function in patients with chronic AF. However, in patients with paroxysmal AF, LA catheter ablation results in decreased LA function. Whether the impairment in LA function is severe enough to predispose to LA thrombi despite elimination of AF remains to be determined.     

Effect of atrial radiofrequency ablation designed to cure atrial fibrillation on atrial mechanical function

INTRODUCTION: The effects of linear radiofrequency lesions in the atria for cure of atrial fibrillation on atrial contraction have not previously been quantified. METHODS AND RESULTS: Atrial function was measured before and 30 +/- 24 days after a biatrial ablation procedure designed to cure atrial fibrillation in eight dogs and after a sham procedure in three dogs. Atrial mechanical function was assessed using Doppler diastolic blood flow velocities, atrial systolic pressure wave amplitude, and assessment of atrial contribution to cardiac output estimated by comparison of AV sequential pacing to ventricular pacing at the same heart rate. The mitral Doppler A/E velocity ratio was 1.03 +/- 0.45 before and 0.72 +/- 0.43 after ablation (P = 0.048). The tricuspid A/E ratio was 0.88 +/- 0.17 before and 0.71 +/- 0.12 after ablation (P = 0.04). The estimated atrial contribution to cardiac output was 18% +/- 9% before and 5% +/- 4% after ablation (P < 0.01). The left atrial systolic pressure wave amplitude was 2.8 +/- 1.5 mmHg before and 1.7 +/- 1.0 mmHg after ablation (P = 0.1). These changes were not observed in control dogs. Lesions covered 25% +/- 6% of the atrial endocardial surface. CONCLUSION: Multiple linear radiofrequency lesions in the atria designed to cure atrial fibrillation may impair atrial contractility. Reduced atrial function is partly due to loss of atrial myocardial mass, but regional delays in atrial activation and splinting of the atria by scarring also may contribute.