ST elevation vs depression

Hi

I don't quite understand the reasons for ST elevation and depression, why is it that an ischemic area of the heart can cause either depression or elevation and not just ONE OF THEM solely. And why is ST elevation usually linked to infarction whilst depression is to ischemia.

I understand the concepts of net dipoles (from Rhodes and Tanner) so if any doctor can explain the above questions to me using these physics principles, it'll be really great, thanks so much

regards

[ajrenalli]

I am not a doctor, but remember the ekg is only an electrical reflection of the heart's current.........the elevation should be reflected with reciprical changes on the other side of the heart.  I hope this helps.