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Mechanism for ST depression associated with contiguous subendocardial ischemia
Bruce Hopenfeld1, Jeroen G Stinstra, Rob S Macleod
1Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah 84112-5000, USA. hopenfel@cvrti.utah.edu
Journal of Cardiovascular Electrophysiology
|October 16, 2004
Summary
ST depression on the heart
Area of Science:
- Cardiac electrophysiology
- Biophysics of myocardial infarction
Background:
- ST depression on the epicardium arises at the border of healthy and ischemic tissue.
- This phenomenon is driven by electrical currents flowing in transmural loops.
- Anisotropic conductivity differences between tissues dictate current flow magnitude and direction.
Purpose of the Study:
- To propose and verify a biophysical mechanism for ST depression.
- To investigate the role of anisotropic conductivity in ST depression.
- To quantify the relationship between ST depression and conductivity differences.
Main Methods:
- Computer simulations using an anatomically accurate, anisotropic model of canine ventricles.
- A bidomain model was employed to represent the effects of ischemia.
- Simulations quantified the link between ST depression and conductivity variations.
Main Results:
- The study verified the proposed mechanism for ST depression.
- Computer simulations quantified the relationship between ST depression and conductivity differences.
- Anisotropic conductivity significantly influences current flow and ST depression.
Conclusions:
- ST depression at the epicardium is observed over the lateral boundary between healthy and ischemic tissue.
- The findings support the proposed current-flow mechanism.
- Anisotropic conductivity plays a crucial role in the manifestation of ST depression.