双房室旁道合并Mahaim纤维(附一例分析)

报道１例束室纤维合并双房室旁道的电生理表现。患者有心动过速史１５年，心电图示右侧游离壁显性旁道，分别于三尖瓣环８点半和５点半处消融阻断旁道，原心电图发生了改变，但存在Ｄｅｌｔａ波。上述两条旁道消融前，ＰＲ间期均为０．０６ｓ，心房递增刺激Ｄｅｌｔａ波增大，房室传导无文氏现象。两条房室旁道消融后，ＰＲ间期为０．１０ｓ、ＡＨ间期１００ｍｓ、ＨＶ间期２０ｍｓ。心房递增刺激时ＡＨ间期逐渐延长且出现文氏型房室阻滞，ＨＶ间期不变、预激程度不变，提示为Ｍａｈａｉｍ纤维（束室支）。心室刺激时逆传Ａ波在Ｈｉｓ束电图最早，提示Ｈｉｓ束逆传。三尖瓣环上未能标测到Ａ、Ｖ波融合。心房、心室刺激未能诱发心动过速。

Electrophysiologic Presentation of a Mahaim Fiber in Patient With Dual Accessory Pathways(Analysis of One Case)

It is reported that one case of patient with bundle ventricular fiber coexisting with dual accessory pathways and its electrophysiologic characteristics.The patient was a 40 year old female with history of supraventricular tachycardia for 15 years.The Electrocardiogram showed right free wall accessory pathway.Ablation at half past 8 oclock and at half past 5 oclock along the tricuspid ring resulted in further changes in QRS morphology but still with the present of Delta wave.Before the ablation of the two accessory pathways,the PR interval was 0.06 s and an increased Delta wave was noted during decremental atrial pacing and no Wenchbach conduction was found.At the successful ablation site,the fusion of AV wave was found to be earlier than the onset of Delta wave.After the ablation of two accessory pathways,the PR interval was 0.10 s,AH interval was 100 ms,HV interval was 20 ms.During the atrial incremental stimulation,the AH interval prolonged gradually with the Wenchbach conduction block and no changes in HV interval and Delta wave.This finding suggests the present of Mahaim fiber.The earliest retrograde atrial activity was recorded at the His bundle area.No AV fusion was found along the tricuspid ring.No tachycardia was induced with the atrial and ventricular stimulation.