| Mechanisms for the maintenance of ventricular fibrillation: the nonuniform dispersion of refractoriness, restitution properties, or anatomic heterogeneities? | |
| | |
MedLine Citation:
|
PMID: 16101633 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
INTRODUCTION: The relative importance of nonuniform dispersion of refractoriness, steep restitution slopes, and anatomic heterogeneities in causing conduction block during ventricular fibrillation (VF) remains unknown. METHODS AND RESULTS: In six open-chest pigs, ventricular refractoriness and restitution curves were estimated from activation recovery intervals (ARIs) calculated from 504 (21 x 24) unipolar electrode recordings 2 mm apart in a plaque sutured to the left ventricular (LV) free wall. A steady-state restitution protocol was performed twice at each of two pacing sites: the LV base and near the left anterior descending artery. VF was electrically induced four times and the incidence of conduction block at each electrode during the first 20 seconds was determined by an automated algorithm. The gradient of the ARI was calculated at each electrode to estimate the spatial dispersion of refractoriness. An exponential curve was fit to the restitution plots of ARIs versus the corresponding diastolic intervals (DIs) for all pacing cycle lengths at each electrode. The locations of epicardial blood vessels were noted after the study. Spatial patterns of conduction block were significantly correlated between the four VF episodes in the same animal (r = 0.66 +/- 0.07, P < 0.05). At the shortest pacing cycle length, the spatial distribution of ARIs, ARI gradients, and restitution slopes was not random but formed clusters of similar values. However, none of these variables was significantly correlated with the incidence of conduction block, even though ARI gradients >2 msec/mm were present between many clusters and approximately 90% of restitution slopes were >1. Instead, conduction block frequently appeared to cluster along epicardial vessels. CONCLUSION: Neither the dispersion of refractoriness nor action potential duration restitution determined during rapid pacing by itself is the major determinant of the location of conduction block during early VF in normal pigs. It may be that these factors interact synergistically with each other as well as with other factors, including anatomic heterogeneities such as those caused by blood vessels, which may be particularly important for the formation of conduction block and maintenance of VF. |
| | |
Authors:
|
Hao Qin; Jian Huang; Jack M Rogers; Gregory P Walcott; Dennis L Rollins; William M Smith; Raymond E Ideker |
Related Documents
:
|
7770373 - Unmasking of retrograde conduction by isoproterenol in a concealed accessory pathway. 2929433 - Factors associated with persistent and transient fascicular blocks in anterior wall acu... 18940533 - Localization of atrial fibrillation triggers in patients undergoing pulmonary vein isol... |
Publication Detail:
|
Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Journal of cardiovascular electrophysiology Volume: 16 ISSN: 1045-3873 ISO Abbreviation: J. Cardiovasc. Electrophysiol. Publication Date: 2005 Aug |
Date Detail:
|
Created Date: 2005-08-16 Completed Date: 2005-12-30 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 9010756 Medline TA: J Cardiovasc Electrophysiol Country: United States |
Other Details:
|
Languages: eng Pagination: 888-97 Citation Subset: IM |
Affiliation:
|
Department of Medicine, University of Alabama, Birmingham, Alabama 35294, USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Cardiac Pacing, Artificial* Female Heart Conduction System / physiopathology Male Refractory Period, Electrophysiological Swine Ventricular Fibrillation / etiology*, pathology, physiopathology |
| Grant Support | |
ID/Acronym/Agency:
|
HL-28429/HL/NHLBI NIH HHS; HL-42760/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Effects of pulmonary vein ablation on regional atrial vagal innervation and vulnerability to atrial ...
Next Document: Assessment of the proarrhythmic potential of the novel antiarrhythmic agent AZD7009 and dofetilide i...