Document Detail

Role of specialized conducting fibers in the genesis of "AV nodal" re-entry tachycardia.
MedLine Citation:
PMID:  6189055     Owner:  NLM     Status:  MEDLINE    
Recent reports have suggested that an accessory bypass tract connecting the His bundle to the atrium (His-atrial fiber) may form the retrograde limb of "AV nodal" re-entry tachycardia (AVNRT). We studied 12 patients with AVNRT in whom the presence of an accessory atrioventricular fiber (Kent fiber) was excluded. We investigated the possibility of a His-atrial (H-A) fiber by examining the nature of retrograde conduction and by assessing the necessity of the atrium as a part of the re-entry pathway. Retrograde conduction through the AV node had characteristics similar to retrograde conduction over a Kent bundle; that is, retrograde conduction times were short and did not vary. With echo beats (Ae) evoked during antegrade refractory period determination early premature beats resulted in prolongation of the AH interval with no change in HAe interval. During AVNRT the A'H':H'A' ratios ranged from 2.0-8.0 (mean 4.0 +/- 1.8) and with changes in tachycardia cycle length the H'A' interval remained constant. During retrograde refractory period determination, delay occurred below the AV node without change in the H-A interval. Estimations of retrograde conduction times by all 3 methods were not significantly different (p greater than 0.2). The pattern of retrograde conduction suggests anatomical or functional specialized fibers as the retrograde limb of the tachycardia. The necessity of the atria as a part of the re-entry circuit was assessed by the introduction of atrial premature beats (APBs) in the region of the atrial septum during AVNRT in 10 patients. APBs pre-excited the atria by 40-140 ms without changing the cycle length of the tachycardia, providing strong evidence against the participation of an extranodal His-atrial fiber in AVNRT. In conclusion, retrograde conduction during AVNRT appears to take place over a functional or anatomical specialized fiber within the AV node and not over an extranodal H-A fiber.
C R Kerr; D W Benson; J J Gallagher
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  6     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1983 Mar 
Date Detail:
Created Date:  1983-06-10     Completed Date:  1983-06-10     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  171-84     Citation Subset:  IM    
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MeSH Terms
Atrioventricular Node / physiopathology*
Bundle of His / physiopathology
Cardiac Pacing, Artificial*
Heart Arrest / physiopathology
Heart Atria / physiopathology
Heart Conduction System / physiopathology*
Middle Aged
Sinoatrial Node / physiology
Tachycardia / diagnosis,  physiopathology*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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