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Retrograde Migration of the Site of Functional Block:
Author(s) -
TCHOU PATRICK J.,
TROHMAN RICHARD,
KIDWELL GREGORY,
MEHDIRAD ALI A.
Publication year - 1996
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1996.tb00534.x
Subject(s) - medicine , block (permutation group theory) , cardiology , mathematics , geometry
Retrograde Migration of Functional Block. Introduction : Functional bundle branch blocks during supraventricular tachycardia have been described, and their sustainment has been attributed to concealed conduction. Such blocks frequently resolve spontaneously, but the electrophysiologic mechanism of resolution bas not been well described. This report describes the resolution of functional bundle branch block through proximal migration of the site of block. Methods and Results : During electrophysiologic study of a patient with reentrant antidromic tachycardia via an atriofascicular accessory pathway, functional retrograde right bundle branch block could be readily induced following tachycardia initiation with right ventricular apical pacing. Resolution of this block was associated with shortening of the tachycardia cycle length. Electrogram recordings along the right bundle branch during tachycardia determined that resolution of the functional retrograde right bundle branch block was associated with migration of the site of block from the distal to the proximal right bundle. When the site of block was directly at the recording site, both anterograde and retrograde activation of the right bundle was demonstrated. Conclusion : Migration of the site of block is a mechanism of resolution for functional conduction blocks maintained by concealed conduction.