| Identification of conduction block in cardiac muscle: in vitro observations in canine epicardium. | |
| | |
MedLine Citation:
|
PMID: 8143309 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
OBJECTIVE: The aim was to examine the ability of several previously proposed criteria and of "vector mapping" to distinguish slow conduction from conduction block in canine myocardium. METHODS: Two different in vitro preparations of canine epicardium were used. In 10 tissues, an anatomical barrier was simulated by a cut (five longitudinal and five transverse to fibre orientation). Eleven tissues removed two weeks after occlusion-reperfusion infarction were also studied. Isochronal activation maps were constructed from extracellular and intracellular recordings and vector loops formed by summing two orthogonally recorded bipolar electrograms were used to indicate the direction of cardiac activation. RESULTS: In the cut model, electrograms recorded from over the anatomical barrier were usually normal or showed double potentials but could occasionally be fractionated. Isochronal activation maps obtained from extracellular recordings were able to identify five of five anatomical barriers transverse to, but only one of five barriers longitudinal to, fibre orientation. The direction of cardiac activation indicated by vector loops identified conduction block in all 10 preparations. In 11 tissues removed from canine ventricles with experimental myocardial infarction, microelectrode recordings were used to characterise regions as either slow conduction or conduction block. Isochronal activation patterns obtained from extracellular recordings generally showed impulses proceeding through zones of conduction and around zones of conduction block but disagreed with the results of microelectrode impalements in two of 11 cases. Electrogram morphology was also not always able to distinguish slow conduction from block. The direction of cardiac activation determined by vector mapping accurately characterised all regions of tissue as showing either slow conduction or conduction block. CONCLUSIONS: Limited regions of conduction block or slow conduction are frequently present in epicardial tissues removed from experimental myocardial infarction. The morphology of extracellular electrograms and isochronal activation mapping performed from extracellular recordings is often but not always able to distinguish slow conduction from conduction block. Vector mapping is useful in distinguishing slow conduction from conduction block in these situations and may help evaluate myocardial conduction patterns. |
| | |
Authors:
|
A Kadish; J Spear |
Related Documents
:
|
6736449 - Amiodarone-induced intra-his block. 1262769 - Reassessment of q waves in left bundle branch block. 7681169 - Rapid resolution of new right bundle branch block in acute anterior myocardial infarcti... 9193039 - Abnormal ventricular repolarization mimicking myocardial infarction after heterocyclic ... 6373269 - Congenital complete heart block. 660019 - The surface electrocardiogram in complete intra-his heart block. 9744439 - Prevention of atrial arrhythmias during ddd pacing by atrial overdrive. 21103749 - Is it time to adopt beating-heart coronary artery bypass grafting? a review of literature. 21472029 - Effects of donepezil on behavioral manifestations of thalamic infarction: a single-case... |
Publication Detail:
|
Type: Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Cardiovascular research Volume: 28 ISSN: 0008-6363 ISO Abbreviation: Cardiovasc. Res. Publication Date: 1994 Feb |
Date Detail:
|
Created Date: 1994-05-02 Completed Date: 1994-05-02 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 0077427 Medline TA: Cardiovasc Res Country: ENGLAND |
Other Details:
|
Languages: eng Pagination: 259-69 Citation Subset: IM |
Affiliation:
|
Department of Internal Medicine, Northwestern University, Northwestern Memorial Hospital, Chicago, IL 60611. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Dogs Electrocardiography Heart Block / diagnosis* Heart Conduction System / physiopathology* Myocardial Infarction / physiopathology Pericardium / physiology, physiopathology |
| Grant Support | |
ID/Acronym/Agency:
|
HL-40667/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Conductance catheter measurements of left ventricular volume in the intact dog: parallel conductance...
Next Document: A1 receptor mediated myocardial infarct size reduction by endogenous adenosine is exerted primarily ...