"Although the pathophysiological determinants for collateral recruitment are largely unknown, the occurrence is related to prolonged periods of ischemia, duration of occlusion, proximal lesion location, and long-term physical exercise".
Circulation. 2006;114:e501-e502.)
© 2006 American Heart Association, Inc
You are correct! Physical exercise has an important role for collateral recruitment as well as duration.
The heart cell hibernation explanation you offer should be framed in gold on this site, well said, kenkeith.
I'd offer this as well:
Coreg is one type of drug that, combined with exercise, awakens these cells and changes changes the health of the heart in a very positive way. My doctor preaches that just taking the drug without exercising daily won't work, it's the combination of drug and exercise that awakens hibernating cells. I've also had wonderful result of mixing in Ranexa, which maximizes the amount of oxygen the heart tissue can accept. That being said, none of this works unless aerobic exercise is mixed in.
When there is a vessel occlusion (100%) the area distal to the blockage does not get sufficient blood/oxygen (ischemia)... I have 100% blockage of the LAD and collateral vessels form a natural by-pass... Sometimes when the heart cells are not getting sufficient blood the heart cells go into what is medically referred to as heart cell hibernation. When a vessel is opened to the deprived area the cells may begin to function normally.
An MI (heart attack from a clot, etc.) is an acute condition that usually causes necrotic cell damage (probably a few hour window for no damage with intervention) and a permanent loss of cell functionality. This can happen with gradual ischemia as well. So a 100% blockage of a coronary artery may or may not result in the same tissue damage as an MI.