Role of calcium cycling versus restitution in the mechanism of repolarization alternans
Details
Serval ID
serval:BIB_4A2C688D5C92
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Role of calcium cycling versus restitution in the mechanism of repolarization alternans
Journal
Circulation Research
ISSN
1524-4571 (Electronic)
Publication state
Published
Issued date
04/2004
Volume
94
Number
8
Pages
1083-90
Notes
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Apr 30
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Apr 30
Abstract
T-wave alternans, a powerful marker of arrhythmic events, results from alternation in action potential duration (APD). The underlying cellular mechanism of APD alternans is unknown but has been attributed to either intracellular calcium (Ca2+) cycling or membrane ionic currents, manifested by a steep slope of cellular APD restitution. To address these mechanisms, high-resolution optical mapping techniques were used to measure action potentials and Ca2+ transients simultaneously from hundreds of epicardial sites in the guinea pig model of pacing-induced T-wave alternans (n=7). The pacing rates (ie, alternans threshold) at which T-wave (369+/-11 bpm), APD (369+/-21 bpm), and Ca2+ (371+/-29 bpm) alternans first appeared were comparable. Importantly, the site of origin of APD alternans and Ca2+ alternans consistently occurred together near the base of the left ventricle, not where APD restitution was steepest. In addition, APD and Ca2+ alternans were remarkably similar both spatially and temporally during discordant alternans. In conclusion, the mechanism underlying T-wave alternans in the intact heart is more closely associated with intracellular Ca2+ cycling rather than APD restitution.
Keywords
Action Potentials
Analog-Digital Conversion
Animals
Arrhythmia/*physiopathology
Calcium Signaling/*physiology
Cardiac Pacing, Artificial
*Electrocardiography
Female
Fluorescent Dyes/analysis
Guinea Pigs
Heart Conduction System/*physiopathology
Heart Ventricles/physiopathology
Image Processing, Computer-Assisted
Kinetics
Pyridinium Compounds/analysis
Pubmed
Web of science
Open Access
Yes
Create date
28/01/2008 10:04
Last modification date
20/08/2019 13:57