Chances of brain death are likely if the heart stopped for:

The brain begins to die after approximately 4-6 minutes without oxygen. This is typically the amount of time it takes for the brain to start dying after the heart stops, as the heart is no longer able to pump oxygenated blood to the brain. However, this can vary depending on a number of factors, including the person's overall health, age, and the circumstances surrounding the heart stoppage.

Here are the steps:

1. The heart stops beating. This could be due to a heart attack, a severe injury, or another serious medical condition.

2. Without the heart pumping blood, oxygen can't reach the brain. The brain needs a constant supply of oxygen to function.

3. After about 4-6 minutes without oxygen, brain cells begin to die. This is because they can't function without oxygen.

4. If the heart isn't restarted within this time frame, the person will likely experience brain death. This is a state in which the brain has lost all function and the person is no longer alive.

5. Even if the heart is restarted after this time frame, the person may have suffered significant brain damage. This could result in a coma, vegetative state, or other serious conditions.

6. The exact time frame can vary depending on a number of factors. For example, if the person is young and healthy, they may be able to survive slightly longer without oxygen. However, in general, the brain begins to die after about 4-6 minutes without oxygen.