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Sci Tech
Brain wins supremacy battle
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Contractions of the heart (heartbeat) do not begin in the heart's upper chamber but in the veins leading to the heart. The rhythms that start in the veins are in turn triggered by the brain, says R. Prasad.
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The four pulmonary veins, which bring pure blood from the lungs to the heart have been found to contract a shade later than the three systemic veins.
WANT TO ask a child a very tough question? Very simple. Just ask him which organ is more important — the brain or the heart. It's akin to asking him whom he likes the most — father or mother? And well, the heart most likely wins hands down.
After all heart and life are not mutually exclusive. Why even doctors declare a person dead only based on the heart's condition. Remember, a person can be kept alive even when the brain is dead but not when the heart fails.
But this long held paradigm is now being challenged. Dr. Solomon Victor, Director of The Heart Institute, Vijaya Health Centre, Chennai, is convinced that the heart does not function independently but is in turn controlled by the brain like any other organ or action/reaction taking place in our body. "We have found the contractions of the heart (heartbeat) do not begin in the heart's upper chamber but in the veins leading to the heart.
The rhythms which start in the veins are in turn triggered by the brain," says Dr. Solomon.
He has found a similar pattern in various life forms including reptiles, birds and mammals.
Even in the simplest forms like the lobster the brain controls the heart. Here the nervous control of the heart is simple through ganglia situated outside the heart.
In the case of humans the sinoatrial node located in the left atrium produces the rhythmic activity, which causes the upper chamber followed by the lower chamber to beat rhythmically.
The sinoatrial node is considered as the pacemaker in the heart, which causes the heart to beat at about 0.8 seconds. In conventional knowledge the heart is thus considered to have a muscle based rhythm.
It's well known that the left atrium contracts a shade later than the right atrium. So is the case with the left and right ventricles. Now Dr. Solomon has found four pulmonary veins, which bring pure blood from the lungs to the heart contracting a shade later than the three systemic veins (carrying impure blood to the lungs). "The two groups of veins triggering in sequence create a duet," says Dr. Solomon.
Similarly, the three systemic veins contract first followed by the right upper atrium and then the lower part of the right atrium. Likewise, the four pulmonary veins contract first followed by the left upper atrium and then the lower part of the left atrium. This sequential contraction of the veins followed by the upper part and then the lower part of the atriums is called the Systemic and Pulmonary Waltz.
In the human embryo the ventricle forms first and starts beating. Only when it is connected to the upper chambers does the atrium take over.
"In an adult the complex pulsating mechanisms of the systemic veins happen even before the sinoatrial node comes into picture. The sinoatrial node cannot create this pulsation which calls for co-ordination of seven veins," says Dr. Solomon emphatically.
"On the other hand the vein pulsation should be initiated by the brain through a network of nerves." And again the co-ordination between the systemic veins and sinoatrial node pulsation is through some neurogenic mechanism. Videography in conjunction with ECG has confirmed that the veins pulsate earlier than the sinoatrial node.
Dr. Solomon had published his findings in the Annals of Royal College of Surgeons of England and presented it in several international conferences.
More compelling evidence comes in the form of the rich nervous connection of the sinoatrial node to the brain. It can thus be safely assumed that the nerve stimulus and chemical mediators start the ion exchange in the sinoatrial node followed by stimulus for the heart to beat (action potential).
But what really happens when the patient is said to be brain dead? In these persons the heart continues to beat though the brain is already dead. "Rhythmic oscillatory centres which brings about the pulsation, have been identified in the brain, spinal cord and in the nerve ganglia outside and inside the heart.
And a lowest in the hierarchy of command centres which initiates the pulsation and which lies inside the heart takes over in such brain dead patients," explains Dr. Solomon.
Proof of such take over is seen when the heart continues to beat even when disconnected from the brain during a heart transplant operation.
Possibly the same mechanism which keeps the heart beating during heart transplant should be operating even in the case of brain dead patients.
The offshoot of this finding is the need for emphasising the necessity of calming the brain through various means such as meditation, yoga and positive emotions. The positive correlation between taking charge of the mind that is running amok or under stress and controlling or avoiding blood pressure and stress induced heart diseases cannot be better proved.
Already the role of meditation in calming the mind and improving one's health is very well known. If you needed a scientific validation to confirm this before you believed it then Dr. Solomon's work does just that.
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