Document Detail


The elusive extracellular AV nodal potential: studies from the canine heart, ex vivo.
MedLine Citation:
PMID:  12391419     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Various forms of extracellular recordings from the AV node (AVN) have been reported. However, lack of consistent validation have precluded the use of such recordings in experimental and clinical studies. In 14 Langendorff perfused dog hearts, the triangle of Koch (TOK) was exposed and an octapolar electrode catheter (2 mm rings, 2 mm spacing) was inserted under the endocardium so that the bipolar pairs recorded electrograms from the apex to the base of the TOK. All recording were filtered between 0.05 and 250 Hz, except for a His bundle (Hb) recording (30-250 Hz) made from another bipolar electrode catheter placed in the aortic root. Transmembrane action potentials (AP) were recorded close to the sites of extracellular electrograms. Pin electrodes at the periphery of the bath were arranged to register two ECG leads from the volume conductor. During recovery of electrical activity 11 of 14 preparations developed a junctional rhythm that initially manifested only an AV nodal extracellular and corresponding intracellular AV nodal potentials followed gradually by conduction to the Hb and ventricles but no retrograde atrial activation; 3 preparations initially produced Hb rhythms based on extracellular and transmembrane AP recordings from the AVN and Hb. The amplitude and duration of the AVN extracellular potentials (average: 97 +/- 26 microV and 92 +/- 25 msec, respectively) during AVN rhythms, significantly differed from those during atrial pacing (262 +/- 185 microV and 78 +/- 26 msec, p < 0.05). Histologic sections of the sites underlying the electrodes recording AVN potentials showed AVN tissue throughout. We conclude that extracellular AV nodal potentials are independent waveforms with specific qualitative and quantitative characteristics that distinguish them from adjacent atrial, transitional, Hb or ventricular potentials.
Authors:
Benjamin J Scherlag; Eugene Patterson; Warren M Jackman; Ralph Lazzara
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Validation Studies    
Journal Detail:
Title:  Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing     Volume:  7     ISSN:  1383-875X     ISO Abbreviation:  J Interv Card Electrophysiol     Publication Date:  2002 Aug 
Date Detail:
Created Date:  2002-10-22     Completed Date:  2003-02-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9708966     Medline TA:  J Interv Card Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  39-52     Citation Subset:  IM    
Affiliation:
University of Oklahoma Health Sciences Center, Cardiac Arrhythmia Research Institute and Department of Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA. benjamin-scherlag@ouhsc.edu
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology*
Animals
Atrioventricular Node / physiology*,  ultrastructure
Bundle of His / physiology,  ultrastructure
Cardiac Pacing, Artificial
Dogs
Electrodes, Implanted
Electrophysiologic Techniques, Cardiac / instrumentation,  methods*,  standards
Extracellular Space / physiology*
Isotonic Solutions
Models, Animal*
Time Factors
Chemical
Reg. No./Substance:
0/Isotonic Solutions; 0/Tyrode's solution

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


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