Chuck Bednar for redOrbit.com – @BednarChuck
Commonly held theories about the moments just before death suggest that a person’s systems begin to slow down as the heart stops beating, ending blood flow to the body, but a new study from researchers at the University of Michigan Medical School suggests otherwise.
Instead, senior author Dr. Jimo Borjigin, an associate professor of neurology and molecular and integrative physiology, and her colleagues write that there is a sudden storm of brain activity that takes place as the heart deteriorates that may play a key role in the demise of heart function – in fact, they believe that brain signaling at near-death could even speed up the process.
Discovering the brain-heart connection in rat studies
Dr. Borjigin’s team, who published their findings in this week’s edition of PNAS Early Edition, included experts with background in cardiology, neuroscience, physiology, pharmacology and chemistry, all of whom analyzed the mechanisms through which the heart of a healthy individual suddenly ceases to function mere minutes after it no longer received oxygen.
Using rats as the subject of their research, they simultaneously examined both the heart and brain during experimental asphyxiation, witnessing the release of over a dozen neurochemicals as well as the activation of brain-heart connectivity processes. As the heart rate sharply fell, brain signals strongly synchronized with heart rhythm, according to new electrocardiomatrix technology.
Blocking signals from the brain during a heart attack
Blocking the brain’s activity led to a significant delay in ventricular fibrillation, the most serious type of cardiac rhythm disturbance and a condition in which the heart’s lower chambers begin to quiver, preventing blood from pumping. The results suggest that blocking the brain’s electrical connections to the heart during cardiac arrest could improve a patient’s chances of survival.
“Despite the loss of consciousness and absence of signs of life, internally the brain exhibits sustained, organized activity and increased communication with the heart, which one may guess is an effort to save the heart,” Dr. Jimo Borjigin said, adding that a “pharmacological blockade” of brain-to-heart communication could potentially keep a heart attack from becoming fatal.
In previous research, he and his colleagues reportedly demonstrated significant and organized activation of brain functions in animals during cardiac arrest. They note that their new research provides “a neurochemical foundation” for the increase in brain activity, as well as a brain-to-heart link that could effectively be targeted in order to prolong detectable brain activity.
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