In the moments before death, the heart plays a central role, conventional wisdom says. That is, as the heart stops beating and blood stops flowing, the rest of the body slowly shuts down. But new research suggests this view may be wrong.
Scientists studied the heart and brain activity of rats in the moments before the animals died from lack of oxygen and found that the animals’ brains sent a flurry of signals to the heart that caused irrevocable damage to the organ, and in fact caused its demise. When the researchers blocked these signals, the heart survived for longer.
If a similar process occurs in humans, then it might be possible to help people survive after their hearts stop by cutting off this storm of signals from the brain, according to the study published in the journal Proceedings of the National Academy of Sciences.
“People naturally focus on the heart, thinking that if you save the heart, you’ll save the brain,” said study co-author Jimo Borjigin, a neuroscientist.
But her team found something surprising. “You have to sever the chemical communication between the brain and heart in order to save the heart,” Borjigin told media, adding that the finding is “contrary to almost all emergency medical practice.”
Every year, more than 400,000 people experience cardiac arrest, which is when the heart stops beating. Even with medical treatment, only about 10 percent survive and are discharged from the hospital.
The researchers addressed the question of why the heart of a previously healthy person suddenly stops functioning completely, after only a few minutes without oxygen.
It turns out that even when a person in cardiac arrest loses consciousness and shows no signs of life, the brain continues to be active. In a previous study published in 2013, Borjigin and her colleagues found that as the heart is dying, it gets flooded with signals from the brain, probably in a desperate attempt to save the heart.
This barrage of signals may be responsible for the near-death experiences some people report.