| Spatiotemporal dynamics of reentrant ventricular tachycardias in canine myocardial infarction: pharmacological modulation. | |
| | |
MedLine Citation:
|
PMID: 12774847 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
During the transition from a slow to rapid depolarization rhythm, rate-dependent sodium channel blockade develops progressively and increases from beat to beat under procainamide but more abruptly under lidocaine. We investigated the consequences of such differences on the dynamic course and stability of reentrant tachycardias at their onset. Procainamide and lidocaine were infused to equipotent plasma concentrations in canines with three-day-old myocardial infarction. We measured the activation times (ms) and maximum slopes of negative deflections in activation complexes (absolute value: /-dV/dt(max)/ in mV/ms) in 191 unipolar electrograms recorded from ischemically damaged subepicardial muscle during programmed stimulation inducing reentrant tachycardias. Procainamide caused a greater reduction in /-dV/dt(max)/ than did lidocaine in the responses to basic stimulation, and it favored the occurrence of cycle length prolongation at tachycardia onset as the /-dV/dt(max)/ decreased progressively in successive beats. This resulted in conduction block and tachycardia termination in three of eight preparations. In contrast, lidocaine caused a greater depression in /-dV/dt(max)/ in response to closely coupled extrastimuli, but /-dV/dt(max)/ remained constant or even improved thereafter, and none of the tachycardias terminated spontaneously under lidocaine (n = 9). However, the reentrant circuits remained spatially unstable, and lidocaine favored the occurrence of cycle length dynamics displaying constant or decreasing trends. This study supports the notion that cycle length dynamics at tachycardia onset are determined by the properties of the reentrant substrate and their pharmacological modulation. |
| | |
Authors:
|
François Hélie; Alain Vinet; René Cardinal |
Related Documents
:
|
2910147 - Polymorphic ventricular tachycardia. 2050917 - Reduction in defibrillator shocks with an implantable device combining antitachycardia ... 3720767 - Ventricular late potentials and inducible ventricular tachyarrhythmias as a marker for ... 6869567 - Effect of coronary occlusion on arrhythmias and conduction in the ovine heart. 1351547 - Intravenous magnesium sulphate in suspected acute myocardial infarction: results of the... 6143967 - Increased cerebral ventricular volume in monozygotic twins discordant for alcoholism. |
Publication Detail:
|
Type: In Vitro; Journal Article |
Journal Detail:
|
Title: Canadian journal of physiology and pharmacology Volume: 81 ISSN: 0008-4212 ISO Abbreviation: Can. J. Physiol. Pharmacol. Publication Date: 2003 May |
Date Detail:
|
Created Date: 2003-05-30 Completed Date: 2004-01-23 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 0372712 Medline TA: Can J Physiol Pharmacol Country: Canada |
Other Details:
|
Languages: eng Pagination: 413-22 Citation Subset: IM |
Affiliation:
|
The Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin Boulevard West, Montréal, QC H4J 1C5, Canada. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Anti-Arrhythmia Agents / pharmacology Dogs Electrocardiography Female Heart Rate / drug effects Lidocaine / pharmacology Male Myocardial Infarction / complications, physiopathology* Procainamide / pharmacology Tachycardia, Ventricular / drug therapy*, etiology, physiopathology* Time Factors |
| Chemical | |
Reg. No./Substance:
|
0/Anti-Arrhythmia Agents; 137-58-6/Lidocaine; 51-06-9/Procainamide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: The role of sex steroids in forming anxiety states in female mice.
Next Document: Bioavailability of anthocyanidin-3-glucosides following consumption of red wine and red grape juice.