Dobreanu D, Micu S, Toma Oana, Rudzik Roxana
University of Medicine and Pharmacy & Cardiovascular Disease and Transplant Institute, Târgu Mureş, Romania.
Rom J Intern Med. 2007;45(1):35-46.
Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common causes of paroxysmal supraventricular tachycardia. For many years, the pharmacological approach was the only therapeutic modality available for managing this arrhythmia. More recently transcatheter radiofrequency (RF) ablation has become a safe and effective alternative to medical therapy. During the last 2 years, 20 patients with AVNRT were evaluated in our department. The diagnosis was made using the classical electrophysiological protocols with three multipolar catheters placed in AV node-His region, coronary sinus and a mapping/ablation catheter. In all cases, a discontinuous AV conduction curve during programmed atrial stimulation with progressively increasing prematurity was demonstrated associated with AV nodal echo beats and induction of the arrhythmia. Typical AVNRT was present in 19 patients. One patient with typical AVNRT also had inducible unusual (slow-slow) AVNRT. An additional patient had unusual slow-slow variant of AVNRT. The arrhythmia was treated in all cases by RFA of the slow AV node pathway, guided by anatomic and electrophysiologic criteria. RF ablation was successful in all patients. Two patients had clinical recurrence of arrhythmia; all have undergone successful reablation. No patient had significant complications of the procedure. As intraprocedural predictors for successful RF ablation were considered the slow pathway potentials with evidence of the junctional accelerated rhythm during RF current delivery and modification of AV node physiology with noninducibility of arrhythmia after RF ablation. The persistence of slow pathway with or without single AV node echo beat during a limited numbers of atrial extrastimuli was accepted as a successful procedure. In all cases, the AV node physiology was tested also after autonomic modulation of AV node. In both cases with clinical recurrence, the intraprocedural RF ablation results were misevaluated probably because of the autonomic modulation of fast pathway electrophysiology masking the persistence of slows pathway conduction. In conclusion invasive electrophysiological evaluation and RF ablation not only eliminate AVNRT, but also provide a unique opportunity to gain insights into the complexity of AV node physiology. This complexity makes more difficult the evaluation of the success of slow pathway ablation for AVNRT and a careful examination of multiple criteria is necessary for a good procedural result.
房室结折返性心动过速（AVNRT）是阵发性室上性心动过速最常见的病因之一。多年来，药物治疗一直是治疗这种心律失常的唯一可用方法。最近，经导管射频（RF）消融已成为一种安全有效的替代药物治疗的方法。在过去两年中，我们科室对20例AVNRT患者进行了评估。诊断采用经典的电生理方案，将三根多极导管分别置于房室结-希氏束区域、冠状窦和标测/消融导管。在所有病例中，程控心房刺激时，随着提前期逐渐增加，出现不连续的房室传导曲线，并伴有房室结回波搏动和心律失常的诱发。19例患者为典型AVNRT。1例典型AVNRT患者还可诱发不寻常的（慢-慢型）AVNRT。另有1例患者为不寻常的慢-慢型AVNRT变异型。所有病例均采用以解剖和电生理标准为指导的慢房室结径路射频消融术治疗心律失常。所有患者射频消融均成功。2例患者心律失常临床复发；均再次成功消融。无患者出现该手术的严重并发症。作为射频消融成功的术中预测指标，考虑在射频电流发放期间出现慢径路电位并有交界性加速心律的证据，以及射频消融后心律失常不能诱发，提示房室结生理功能改变。在有限次数的心房额外刺激期间，慢径路持续存在且有或无单个房室结回波搏动被视为手术成功。在所有病例中，还在对房室结进行自主神经调制后测试了房室结生理功能。在两例临床复发的病例中，术中射频消融结果可能被误判，可能是因为快径路电生理的自主神经调制掩盖了慢径路传导的持续存在。总之，有创电生理评估和射频消融不仅消除了AVNRT，还为深入了解房室结生理功能的复杂性提供了独特的机会。这种复杂性使得评估AVNRT慢径路消融的成功率更加困难，为获得良好的手术效果，需要仔细检查多个标准。
