The blood supply to the brain immediately cut off as soon as the heart stops beating and this will be the official time of death of a person. However, researchers have discovered that, despite the fact that the heart isn't beating, the brain remains working and still hears what other people say.
What Happens To The Brain When The Heart Stops Beating?
Often, heart attack and cardiac arrest are believed to be the same, yet as per the American Heart Association (AHA), the conditions are totally different. Heart attack is when the blood couldn't reach a section of the heart due to a blocked artery - causing that portion to die, but the heart remains thumping.
On the other hand, the electrical signals that stimulate the pumping activity of the heart in cardiac arrest become obstructed — the heart stops thumping and death takes after. Majority of the terminal cases, doctors declare the death as soon as the patient no longer has a heartbeat.
"Technically speaking, that's how you get the time of death - it's all based on the moment when the heart stops," said Dr. Sam Parnia, director of critical care and resuscitation research at NYU Langone School of Medicine in New York City.
You're Aware Of Your Own Death
The cerebral cortex of the brain, known as the thinking part, additionally backs off, then flatlines — no visible brainwaves on the electric screen — within two to 20 seconds. This will provoke a chain response of cell forms prompting the demise of brain cells, though it takes hours after the heart stops beating.
According to Parnia, giving the patient a cardiopulmonary resuscitation (CPR) could deliver blood to the brain for around 15 percent of what's needed to work. This procedure is sufficient to delay the death trajectory of brain cells, however, it's not sufficient to kick the brain to function again, the reason why patients have no reflexes when performing the CPR.
Animals also have heightened brain activity after death, while people may, in any case, have some type of consciousness amid the first phase of their death. Substantial anecdotal evidence has shown that patients whose heart stopped thumping and beats again were able to recall what's happening around them.
Going Back To Life After Death
The team will observe the brain in details during the course of a cardiac arrest, revival, and death to know the amount of oxygen is needed to reach the brain, when the cortex comes "back online," and how to relate these experiences to the activity of the brain itself.
"We're trying to understand the exact features that people experience when they go through death, because we understand that this is going to reflect the universal experience we're all going to have when we die," Parnia said.
As of now, the team explores the pervasiveness of awareness after death. They were searching for a vast number of people in the United States and in Europe who have encountered cardiac arrest for the largest study.