Medical science believed for a long time that moments before death the heart stops beating and thus blood flow within the body stops. This causes the body to shut down. However, new research conducted in the area has a radically different proposition to make.
In a recently published study in Proceedings of the National Academy of Sciences, heart and brain activities of rats were recorded that were dying from lack of oxygen. It was observed that the brain sent rapid instructions to the heart, just before death, causing fatal damage to the organ. Interestingly, when researchers blocked this signal from the brain, the hearts of the lab rats survived much longer.
The method followed was to subject the rats to carbon dioxide or lethal injection, to induce cardiac arrest. Using EEG the brain activity was monitored, and hearts were monitored by EKG. As the heart rates dropped off, the brain activity tended to synchronize with the heart’s activity. As soon as this happened there was a rush of neurochemicals such as dopamine (produces feelings of pleasure) and nor-epinephrine (produces feelings of alertness). The flow of these chemicals was blocked via severing of the spinal cord to delay cardiac arrest and the animals survived three times longer than the control group. This opens up the possibility that this may be applicable to humans if their hearts are damaged by similar signals.
“Whether human bodies behave similarly is the million-dollar question” this is the main concern of the study’s co-author Jimo Borjigin, a neuroscientist at the University of Michigan Medical School in Ann Arbor. He also talked about a debate relating to the activities of brain and heart just before death, “People naturally focus on the heart, thinking that if you save the heart, you’ll save the brain…you have to sever [the chemical communication between] the brain and heart in order to save the heart,” which is “contrary to almost all emergency medical practice,” Borjigin told Live Science.
Nearly a half million Americans suffer from cardiac arrest each year, with only about 10% surviving these incidents. Studies show that even during cardiac arrest, the brain continues to function. Borjigin thinks that the flooding of the heart with signals from the brain is likely an attempt to save the heart, and may even be responsible for near-death experiences. If the study is carried forward and the brain-heart connection is severed, it would be possible to treat cardiac arrest in more efficient manner.