Insufficient supply of oxygenated blood to the heart?

The main thing that happens is that the heart would not be able to pump blood efficiently to all parts of the body, as a result of which all parts of the body would receive lesser and lesser oxygen. This can cause:

* Nausea * Vomiting

* Prolonged lack of oxygen may cause fainting As the oxygen supply continues to keep dwindling, the blood & oxygen supply to vital organs only will be maintained and supply to all other parts would be shut down. This is to ensure that the vital organs like the brain, heart etc continue to receive what little oxygen that is available to ensure life.

After some point of time, people would faint and then continue lack of oxygen may even cause death within hours...