节点文献
心房颤动维持机制的电标测和频谱分析
【作者】 黄雯；
【导师】 姚焰；
【作者基本信息】 北京协和医学院 ， 内科学， 2012， 博士
【摘要】 [研究背景]：心房颤动(房颤)的诊断基于其能触发并且维持,在一些文章中房颤(Atrial Fibrillation, AF)的诱发常被用作检验房颤射频消融效果的指标。但对于正常人是否也能诱发房颤则知之甚少。本研究第一部分的目的是探讨无房颤病史者发作房颤的可能性。[研究方法]：本研究共前瞻性连续入选86名临床无房颤发作病史者,这些患者因阵发性室上性心动过速(Supraventricular Tachycardia, SVT)来我院行射频消融治疗。在电生理检查和成功消融SVT后采用两种心房快速刺激方法进行AF的诱发性评价。首先,于冠状静脉窦口(Coronary Sinus Ostium, CSO)采用三种不同频率心房起搏,每次起搏5S,重复3次。接着,采用同一电极通道对同一例病人进行连续递增刺激,由250ms开始以10ms的步长连续递增直至心房1：1失夺获或诱发AF,这种方法同样重复3次。[研究结果]：采用第一种心房刺激方案共诱发出3例AF(3.5%),而第二种方案共有22例患者诱发出AF(25.6%),其中16例为可维持AF(18.6%)。第二种方案的AF诱发率明显高于第一组。另外,在第二种方案中,1：1心房失夺获时的周长<180ms者更易诱发出AF(21/63vs1/23；P=0.006)。[结论]：在心房快速递增刺激下26%的无房颤发作病史者可发作房颤,18.6%的患者AF发作时间超过5分钟。该研究结果提示房颤病史的存在并非在于房颤能否触发,更重要的在于其维持机制。[研究背景]：持续性房颤(Persistent Atrial Fibrillation, PeAF)的导管消融治疗仍是目前电生理界的一大难题,其维持机制尚不明确。本研究的目的是采用同步频谱分析研究PeAF时左房的激动分布特点,以确定PeAF得以维持的关键基质。[研究方法]：连续入选于我院行非接触标测指导下初次射频消融的PeAF患者。提取患者消融前非接触标测系统记录的房颤时左房内2048个点的同步激动数据。将带有左房模型和电位信息的激动数据导入Matlab系统中进行左房频谱分析以确定PeAF发作时左房的高频激动区域。记录射频消融过程中房颤的电生理变化及消融有效靶点的位置,比较房颤消融有效的位点与高频激动部位的关系。[研究结果]：本研究共入选48例采用非接触式标测进行初次射频消融的PeAF患者(男40例,平均年龄53.35±10.24岁),房颤平均持续时间17.79±24.32个月。术前超声示左房前后径为42.33±5.78mm,31例患者左房增大,其中12例为双房增大。对消融前8034.65±996.85ms房颤时的左房激动数据进行频谱分析显示：左房最高激动频率分布在6.10-11.80Hz之间。48例患者中共发现203处高频激动区(4.23±1.15处/例)：91.67%(44例)的患者左房顶部表现为高频激动,75.00%的患者(36例)于左心耳与左上肺静脉之间的嵴部可见高频激动,左房间隔高频激动见于33例(68.75%)的患者。肺静脉及后壁高频激动较少。递进式线性消融过程中出现共计145处有效反应(140处在左房,5处在右房),其中77.14%消融有效靶点位于高频激动区(95%置信区间：34.22%-82.80%)：消融有效靶点与高频激动区域的吻合率在左房顶部为97.30%、嵴部为93.10%、左房间隔面为75.00%。术中19例(39.58%)患者经消融转复为窦性心律,另有22例患者给予药物静推后转复为窦性心律。随访18.90±6.43个月,37例(77.08%)患者维持窦性心律,其中9例(18.75%)患者因顽固性左房房扑二次消融成功。[结论]：PeAF的左房高频激动区主要位于顶部、嵴部和房间隔面。递进式线性消融77.14%的有效靶点位于高频激动区。同步激动数据的频谱分析有助于确定PeAF的关键基质,可用于指导临床消融策略的制定。根据本研究结果,左房线性消融尤其是顶部消融在PeAF的治疗中是必要的。
【Abstract】 Introduction:The diagnosis of Atrial fibrillation was based on the inducibility and maintenance. While inducibility of atrial fibrillation (AF) is often utilized as an endpoint for RF ablation of AF, little is known regarding inducibility among normals. We therefore evaluated the inducibility of AF with rapid atrial pacing (RAP) in patients without a clinical history of AF, following catheter ablation of supraventricular tachycardia (SVT).Methods:We prospectively evaluated86patients without a history of AF who were referred for catheter ablation of SVT. After routine electrophysiological study and successful ablation of the SVT, two different RAP protocols for induction of AF were tested. First, AF induction was attempted by5-second bursts of atrial pacing from the coronary sinus ostium (CSO) at three different cycle lengths (CL). Next, continuous incremental stimulus(CIS) was performed from the CSO starting at CL250ms to the loss of1:1atrial capture. This protocol was repeated three times for each subject.Results:Three of subjects (3.5%) enrolled had inducible AF with the first pacing protocol. However, with the second protocol, AF was inducible in22patients (25.6%), including sustained AF in16patients (18.6%). There were significant differences in the inducibility of AF between the two atrial pacing protocols. Additionally, with the second pacing protocol, patients with loss of1:1atrial capture at CL<180ms were more easily inducible for AF (21/63vs1/23, P=0.006).Conclusion:Using a specific, atrial decremental pacing protocol,26%of patients without a history of AF had inducible AF, while18.6%lasting>5minutes. These findings suggest that the essence of AF may not be the inducibility but the maintenance. Background:There are great difficulties with the current therapies for persistent atrial fibrillation (PeAF), of which the maintaining mechanism is still unknown. The purpose of this study was to characterize the basic spatial and temporal distribution of atrial activities of PeAF by isochronal spectral analysis, and to identify the crucial substrate maintaining PeAF.Methods:The patients with PeAF referred for the first catheter ablation using a noncontact mapping in our hospital were enrolled. Left atrial activations of PeAF prior to the radiofrequency energy delivering were recorded in the noncontact mapping system. Digital data with geometry and electrograms information at2048locations were acquired and processed into a Custom-written Matlab system for spectral analysis. Regions with high-frequency activities were identified for each case. The dynamic electrophysiological variations and location of effective targets were routine recorded and evaluated. Comparisons were made between the locations of the effective targets and the high-frequency activation regions.Results:Forty-eight patients with PeAF referred for the first catheter ablation using a noncontact mapping were enrolled (male40cases, mean age53.35±10.24years old).The average sustained duration of PeAF was17.79±24.32months. Left atrium enlargement were documented in31patients, while12of which demonstrated bi-atrial enlargement. The average left atrial diameter measured by echocardiography was42.33±5.78mm. The8034.65±996.85ms atrial activation data prior to the ablation were analyzed. Local left atrial activation frequencies of PeAF varied from6.10Hz to11.80Hz. A total of203regions were detected as high-frequency activation regions in48patients (4.23±1.15regions/patient):91.67%(44patients) showed high-frequency activation in left atrial roof,75.00%(36patients) in the ridge between left atrial appendage and left superior pulmonary vein and68.75%(33patients) in the inter-atrial septum. Less high frequency activation located around the pulmonary veins and posterior wall. There were145effective episodes occurred during linear ablation in the48patients (140in left atrium,5in right atrium).77.14%of the effective targets were located within the high frequency activation regions (95%Cl:34.22%-82.80%):The accordance between the effective target and high-frequency activation region was97.30%in the roof,93.10%in the ridge and75.00%in the septum. Nineteen patients(39.58%) with PeAF were converted to sinus rhythm by stepwise linear ablation while another22patients were converted to sinus rhythm after concomitant ibutilide treatment. After an average of18.90±6.43months follow-up,37patients(77.08%) were sustained in sinus rhythm without antiarrhythmics, while9(18.75%) of which experienced a redo successful ablation for refractory left atrial flutter.Conclusions:The high-frequency activation of persistent atrial fibrillation were located in the roof, ridge and septum.77.14%of the effective targets of the stepwise linear ablation were accordance with the high-frequency activation regions. Isochronal spectral analysis would be helpful in identification of the critical substrate of persistent atrial fibrillation and in the option of appropriate ablation strategy. According to the results, left atrial linear ablation, especially the roof line, was essential in the control of persistent atrial fibrillation.