Heald S C, Davies D W, Ward D E, Garratt C J, Rowland E
Cardiology Department, St George's Hospital, London.
Br Heart J. 1995 Mar;73(3):250-7. doi: 10.1136/hrt.73.3.250.
Reentrant tachycardias associated with Mahaim pathways are rare but potentially troublesome. Various electrophysiological substrates have been postulated and catheter ablation at several sites has been described.
To assess the efficacy and feasibility of targeting discrete Mahaim potentials recorded on the tricuspid annulus for the delivery of radiofrequency energy in the treatment of Mahaim tachycardia.
21 patients out of a consecutive series of 579 patients referred to one of three tertiary centres for catheter ablation of accessory pathways causing tachycardia. All had symptoms and presented with tachycardia of left bundle branch block configuration or had this induced at electrophysiological study. In all cases, the tachycardia was antidromic with anterograde conduction over a Mahaim pathway.
6 patients had additional tachycardia substrates (4 had accessory atrioventricular connections and 2 had dual atrioventricular nodal pathways and atrioventricular nodal reentry). After ablation of the additional pathways, Mahaim potentials were identified in 16 (76%) associated with early activation of the distal right bundle branch and radiofrequency energy at this site on the tricuspid annulus abolished Mahaim conduction in all 16 cases. In 2 patients there was early ventricular activation at the annulus without a Mahaim potential but radiofrequency energy abolished pre-excitation. In the remaining patients no potential could be found (1 patient), no tachycardia could be induced after ablation of an additional pathway (1 patient), or no Mahaim conduction was evident during the study (1 patient). During follow up (1-29 months (median 9 months)) all but 1 patient remained symptom free without medication.
Additional accessory pathways seem to be common in patients with Mahaim tachycardias. The identification of Mahaim potentials at the tricuspid annulus confirms that most of these pathways are in the right free wall and permits their successful ablation and the abolition of associated tachycardia.
与Mahaim纤维束相关的折返性心动过速虽罕见，但可能造成麻烦。已提出多种电生理基质，并描述了在多个部位进行导管消融的情况。
评估针对记录于三尖瓣环上离散的Mahaim电位施加射频能量治疗Mahaim心动过速的有效性和可行性。
在连续转诊至三个三级中心之一进行导管消融治疗导致心动过速的旁路的579例患者中，有21例。所有患者均有症状，表现为左束支传导阻滞形态的心动过速，或在电生理检查中诱发该心动过速。所有病例中，心动过速均为逆向型，经Mahaim纤维束前传。
6例患者有额外的心动过速基质（4例有房室旁路连接，2例有双房室结径路和房室结折返）。消融额外的径路后，16例（76%）发现了与右束支远端早期激动相关的Mahaim电位，在三尖瓣环该部位施加射频能量使所有16例患者的Mahaim传导消失。2例患者在瓣环处有早期心室激动但无Mahaim电位，但射频能量消除了预激。其余患者中，未发现电位（1例），消融额外径路后不能诱发心动过速（1例），或在研究期间未发现明显的Mahaim传导（1例）。随访期间（1至29个月（中位时间9个月）），除1例患者外，所有患者未用药均无症状。
额外的旁路在Mahaim心动过速患者中似乎很常见。在三尖瓣环处识别出Mahaim电位证实这些径路大多位于右游离壁，并允许成功消融及消除相关的心动过速。
