Document Detail


Unmasking of retrograde conduction by isoproterenol in a concealed accessory pathway.
MedLine Citation:
PMID:  7770373     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A 52-year-old female with no structural heart disease presented with a right bundle branch block (RBBB)/right axis deviation tachycardia with a cycle length of 300 msec. P waves were not discernible on the surface ECG. Baseline electrophysiology study in the drug-free state revealed no evidence for anterograde or retrograde conducting accessory pathways (APs) or for dual AV node physiology. Retrograde VA block with AV dissociation was present at a ventricular paced cycle length of 600 msec (sinus cycle length of 635-700 msec). AV nodal Wenckebach occurred during decremental atrial pacing at a cycle length of 300 msec. During isoproterenol administration, a left lateral AP with retrograde only conduction became manifest with 1:1 VA conduction to 380 msec. No anterograde AP conduction was present. Orthodromic reciprocating tachycardia with a cycle length of 285-315 msec was easily induced. We conclude that total functional conduction block can exist in APs, and unmasking of total conduction block can be accomplished with isoproterenol. All patients with undiagnosed tachycardias should have full repeat stimulation studies during adrenergic stimulation if the initial baseline evaluation is nondiagnostic.
Authors:
D W Frazier; D L Packer; M S Stanton
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Publication Detail:
Type:  Case Reports; Journal Article    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  18     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1995 Mar 
Date Detail:
Created Date:  1995-07-05     Completed Date:  1995-07-05     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  492-7     Citation Subset:  IM    
Affiliation:
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.
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MeSH Terms
Descriptor/Qualifier:
Bundle-Branch Block / physiopathology*
Cardiac Pacing, Artificial
Electrocardiography
Female
Heart Conduction System / physiopathology*
Humans
Isoproterenol / diagnostic use*
Middle Aged
Chemical
Reg. No./Substance:
7683-59-2/Isoproterenol

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


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