Spontaneous Transition of 2:1 Atrioventricular Block to 1:1 Atrioventricular Conduction during Atrioventricular Nodal Reentrant Tachycardia: Evidence Supporting the Intra-Hisian or Infra-Hisian Area as the Site of Block

Shih Huang Lee, Ching Tai Tai, Chern En Chiang, Wen Chung Yu, Jun Jack Cheng, Yu An Ding, Mau Song Chang, Shih Ann Chen

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Introduction: The incidence of spontaneous transition of 2:1 AV block to 1:1 AV conduction during AV nodal reentrant tachycardia has not been well reported. Among previous studies, controversy also existed about the site of the 2:1 AV block during AV nodal reentrant tachycardia. Methods and Results: In patients with 2:1 AV block during AV nodal reentrant tachycardia, the incidence of spontaneous transition of 2:1 AV block to 1:1 AV conduction and change of electrophysiologic properties during spontaneous transition were analyzed. Among the 20 patients with 2:1 AV block during AV nodal reentrant tachycardia, a His-bundle potential was absent in blocked beats during 2:1 AV block in 8 patients, and the maximal amplitude of the His-bundle potential in the blocked beats was the same as that in the conducted beats in 4 patients and was significantly smaller than that in the conducted beats in 8 patients (0.49 ± 0.25 mV vs 0.16 ± 0.07 mV, P = 0.007). Spontaneous transition of 2:1 AV block to 1:1 AV conduction occurred in 15 (75%) of 20 patients with 2:1 AV block during AV nodal reentrant tachycardia. Spontaneous transition of 2:1 AV block to 1:1 AV conduction was associated with transient right and/or left bundle branch block. The 1:1 AV conduction with transient bundle branch block was associated with significant His-ventricular (HV) interval prolongation (66 ± 19 ms) compared with 2:1 AV block (44 ± 6 ms, P < 0.01) and 1:1 AV conduction without bundle branch block (43 ± 6 ms, P < 0.01). Conclusion: The 2:1 AV block during AV nodal reentrant tachycardia is functional; the level of block is demonstrated to be within or below the His bundle in a majority of patients with 2:1 AV block during AV nodal reentrant tachycardia, and a minority are possibly high in the junction between the AV node and His bundle.

Original languageEnglish
Pages (from-to)1337-1341
Number of pages5
JournalJournal of Cardiovascular Electrophysiology
Volume14
Issue number12
DOIs
Publication statusPublished - Dec 2003
Externally publishedYes

Keywords

  • Atrioventricular block
  • Atrioventricular node
  • Tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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