Kalusche D, Arentz T, Haïssaguerre M
Herz-Zentrum Bad Krozingen Abteilung Interventionelle Kardiologie II Südring 15 D-79189 Bad Krozingen.
Z Kardiol. 2000 Dec;89(12):1141-5. doi: 10.1007/s003920070142.
Atrial fibrillation is the most common sustained arrhythmia causing substantial morbidity and probably increasing the risk of death. Most commonly, it is divided into a paroxysmal form, when--by definition--episodes end spontaneously, or a persistent one that lasts and requires a medical or electrical intervention for its termination. It might be called permanent, when no further attempts seem to be indicated for its elimination. Until recently, therapeutic strategies aimed at preventing cardiac embolism and at restoring and maintaining sinus rhythm by antiarrhythmic drugs. Long-term efficacy of the latter approach is poor, since less than 50% of patients can be maintained in stable sinus rhythm when periods of more than 1 year are considered. Can atrial fibrillation be cured? More than ten years ago Cox and coworkers demonstrated that the surgical compartimentation of both atria (MAZE procedure) is able to abolish atrial fibrillation in up to 90% of patients with chronic paroxysmal and also persistent atrial fibrillation. However, all studies trying to imitate the MAZE procedure by electrophysiological catheter-based techniques applying radiofrequency energy to produce transmural linear lesions were either not successful or showed a non-acceptable complication rate, especially a high rate of cerebrovascular accidents. The rationale behind the principle of compartimentation of the atria is the reduction of the critical atrial muscle mass necessary to facilitate fibrillation of the atria. A different approach aiming especially at the problem of paroxysmal atial fibrillation is based on the observation that there might be a "focal trigger" responsible for the initiation of the atrial tachyarrhythmia and that by eliminating this focal trigger atrial fibrillation can be avoided. This hypothesis was first verified in patients by Haïssaguerre et al., in fact experimental creation of "focal atrial fibrillation" was presented by Moe and Abildskov more than 30 years ago. During the last 3 years the concept of curing paroxysmal atrial fibrillation by applying focal radiofrequency lesions was supported by the results of several groups in more than 200 patients: 60 to 85% of patients can be cured, but in almost half of the cases more than one procedure is necessary. Most interestingly--and this is a finding of all investigators--more than 90% of the triggering ectopic foci are located in the pulmonary veins or in the pulmonary vein/left atrial junction. This concept is also supported by surgical experience from performing pulmonary vein isolations during open heart surgery. Most recently, the concept of eliminating the trigger was extended and applied to patients with established persistent atrial fibrillation. Until now, it has not been well established how many patients with paroxysmal atrial fibrillation are "good candidates" for a focal RF ablation procedure, nor is the risk of the procedure well defined. Besides the necessity of performing a transseptal catheterization there is the risk of cardiac embolism and pulmonary vein stenosis. The endpoint of the procedure is also not well defined: instead of trying to eliminate the "trigger" located in a pulmonary vein, it might be safer to isolate the "arrhythmogenic vein". This however, is a difficult task with current catheter technologies. It can be expected that new catheter designs for mapping and ablation and--maybe--the use of alternative energy sources--e.g., ultrasound, microwave--will make the procedure easier and applicable to more patients with drug refractory atrial fibrillation.
心房颤动是最常见的持续性心律失常，会导致严重的发病率，并可能增加死亡风险。最常见的是，它被分为阵发性形式，根据定义，发作会自发终止；或持续性形式，持续存在且需要药物或电干预才能终止。如果似乎不再需要进一步尝试消除，就可能被称为永久性房颤。直到最近，治疗策略旨在预防心脏栓塞，并通过抗心律失常药物恢复和维持窦性心律。后一种方法的长期疗效不佳，因为在考虑超过1年的时间段时，不到50%的患者能够维持稳定的窦性心律。心房颤动能被治愈吗？十多年前，考克斯及其同事证明，对两个心房进行手术分隔（迷宫手术）能够消除高达90%的慢性阵发性和持续性心房颤动患者的房颤。然而，所有试图通过基于电生理导管技术应用射频能量产生透壁线性损伤来模仿迷宫手术的研究，要么没有成功，要么显示出不可接受的并发症发生率，尤其是脑血管意外的高发生率。心房分隔原则背后的基本原理是减少促进心房颤动所需的关键心房肌质量。一种特别针对阵发性心房颤动问题的不同方法基于这样的观察，即可能存在一个“局灶性触发因素”导致房性快速心律失常的发作，并且通过消除这个局灶性触发因素可以避免心房颤动。这个假设首先由海萨吉尔等人在患者中得到验证，事实上，莫伊和阿比德斯科夫在30多年前就展示了“局灶性心房颤动”的实验性创建。在过去3年里，通过应用局灶性射频损伤治愈阵发性心房颤动的概念得到了几个研究小组在超过第200名患者中的结果支持：60%至85%的患者可以治愈，但在几乎一半的病例中需要不止一次手术。最有趣的是——这是所有研究者的发现——超过90%的触发异位灶位于肺静脉或肺静脉/左心房交界处。心脏直视手术中进行肺静脉隔离的手术经验也支持了这个概念。最近，消除触发因素的概念被扩展并应用于已确诊的持续性心房颤动患者。到目前为止，尚未明确有多少阵发性心房颤动患者是局灶性射频消融手术的“合适候选者”，该手术风险也未明确界定。除了进行经间隔导管插入术的必要性外，还有心脏栓塞和肺静脉狭窄的风险。该手术的终点也未明确界定：与其试图消除位于肺静脉中的“触发因素”，隔离“致心律失常静脉”可能更安全。然而，用目前的导管技术这是一项艰巨的任务。可以预期，用于标测和消融的新导管设计以及——也许——替代能源（例如超声、微波）的使用将使该手术更容易，并适用于更多药物难治性心房颤动患者。
