Preliminary study on the mechanism of 2:1 atrioventricular block during atrioventricular node reentrant tachycardia / 中国介入心脏病学杂志

ABSTRACT

Objective The purpose of this study was to clarify the mechanism of 21 atrioventricular block (AVB) during AV node reentrant tachycardia (AVNRT) induced during electrophysioloic study.Methods In consecutive patients with AVNRT referred for electrophysiologic study, the data of 2 1 AVB during induced AVNRT was retrospectively analysed. Results The data of 4 patients was excluded from analyzing because of the unsatisfactory recording of His bundle potential during AVNRT. A His bundle deflection was present in the blocked beats in three of the remaining 5 patients and absent in the other two. At the beginning of AVNRT induced in those patients whose His bundle deflection was present in the blocked beats, H-V Wenckebach sequence with a QRS pattern of RBBB or LBBB was seen preceding and following the 2 1 AVB. A pattern of H-V Wenckebach phenomenon occurred once during AVNRT with 21 AVB in one of the two patients whose His bundle deflection was absent in the blocked beats.Conclusion The induced 21 AVB during AVNRT is due to functional block in the His-Purkinje system regardless of the presence or absence of a His bundle deflection in blocked beats.