Mechanism for ST depression associated with contiguous subendocardial ischemia.
BACKGROUND
A mechanism for ST depression arising on the epicardial surface over the border between normal and ischemic tissue is proposed. Depression is caused by current flowing in a transmural loop that begins and ends at the lateral boundary between healthy and ischemic tissue and passes through the transmural boundary between healthy and ischemic tissue. The result is ST depression at the epicardium over the lateral boundary. The size and direction of current flow are dictated by differences in the magnitude and orientation of anisotropic conductivity between those boundaries.


RESULTS
Computer simulations verified and quantified the relationship between ST depression and conductivity differences. We used computer simulations based on an anatomically accurate, anisotropic model of canine ventricles and a bidomain representation of the effects of ischemia to verify the biophysical basis of this mechanism.


CONCLUSIONS
ST depression at the epicardium appears over a lateral boundary between healthy and ischemic tissue.
Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah 84112-5000, USA. hopenfel@cvrti.utah.edu
Bruce
B
Hopenfeld
Jeroen G
JG
Stinstra
Rob S
RS
Macleod
D003198:Computer Simulation; D004562:Electrocardiography; D004699:Endocardium; D006329:Heart Conduction System / Q000502:physiology*; D017202:Myocardial Ischemia / Q000503:physiopathology*; D010496:Pericardium / Q000502:physiology