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What Causes Cardiac Pre-scope Following Increased Heart Rate?
Question: Hello! I had a episode of presyncope today. It happend during school. We did check each others heart rate (with a machine) and was checking how it changes with inspiration/expiration and when holding our breath for a little while. I had a high pulse (around 100) and did just hold my breath for like 10-20 sec. Shortly after that though I felt exactly like I got a massive fall in blood pressure and like I was about to faint. My heart rate was rising, I started sweating, felt weak and my visual field got brighter and brighter. I did lay my head down and focused on breathing and it subsided after a few minutes. What do you think happend? My heart rate also seemed to rise when I held my breath (the opposite from my friends response), what does that mean? And was it a fall in BP or something else that gave me this reaction?
Brief Answer:
Indeed a fainting spell.
Detailed Answer:
Hi,
Your description indeed sounds like fainting spell. There may be couple of changes that may have triggered it.
1. Cardiac prescope following increased heart rate and blood pressure changes
2. Increased carbondioxide level within blood circulation (hypercapnia) upon holding breathe
Both these are physiological changes which lead to reduced brain circulation making you faint. It doesn't sound to be pathological, therefore we need not be worried.
Hope this answered your question. Let me know if you need clarifications.
Regards
Indeed a fainting spell.
Detailed Answer:
Hi,
Your description indeed sounds like fainting spell. There may be couple of changes that may have triggered it.
1. Cardiac prescope following increased heart rate and blood pressure changes
2. Increased carbondioxide level within blood circulation (hypercapnia) upon holding breathe
Both these are physiological changes which lead to reduced brain circulation making you faint. It doesn't sound to be pathological, therefore we need not be worried.
Hope this answered your question. Let me know if you need clarifications.
Regards
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thanks for the answer!
A few follow-up questions/clarifications:
Could you explain the connection between hypercapnia - blood pressure - fainting?
Since my breath-holding was so short I was thinking more along the line that I might have been hyperventilating afterwords (not on purpose of course) But how does hyperventilation affect blood pressure? Got different sources saying it vasoconstrict or vasodilate - what is the correct answer and how does it affect the big picture? (i.e. me nearly fainting)
What got me worried was that it also may be heart-related, since I don't understands how a high pulse and no shift in position could have got the blood pressure to fall? Could you clarify how the brain-circulation can be affected anyway?
Also, could the reduced brain circulation during a fainting episode harm the brain in any way?
Thank you again!
A few follow-up questions/clarifications:
Could you explain the connection between hypercapnia - blood pressure - fainting?
Since my breath-holding was so short I was thinking more along the line that I might have been hyperventilating afterwords (not on purpose of course) But how does hyperventilation affect blood pressure? Got different sources saying it vasoconstrict or vasodilate - what is the correct answer and how does it affect the big picture? (i.e. me nearly fainting)
What got me worried was that it also may be heart-related, since I don't understands how a high pulse and no shift in position could have got the blood pressure to fall? Could you clarify how the brain-circulation can be affected anyway?
Also, could the reduced brain circulation during a fainting episode harm the brain in any way?
Thank you again!
Brief Answer:
No harm caused...
Detailed Answer:
Well, I shall try explaining...
Blood pressure, heart rate as well as blood gas levels change with breathing. These changes are quite natural and physiological. When an individual hold breath, there is marginal drop in heart rate as well as rise in blood carbondioxide level. Blood pressure may also drop as the individual continues to voluntarily hold breathe. Both lower heart rate as well as blood pressure reduced brain circulation. Increased carbondioxide also leads to reduced consciousness. All of these factors together combined may lead to near fainting - loss of consciousness.
Hyperventilation has a different set of mechanism. You breath hard and fast during hyperventilation. This hyperventilation drives away cardondioxide from blood. We require enough amount of blood carbondioxide to keep the ventilation (breathing) driving. And thus carbondioxide flush away creates sense of suffocation without the drive to breathe.
I am sorry, if the above description is confusing. However these physiological changes with respect to heart rate, blood pressure, carbondioxide level and so on are quite complex and not easily understandable.
Though the set of physiological changes are complex and difficult to digest, the fact remains. You had those features as well as near fainting spell as a result of body physiology. Nothing pathological about it. And as the body is able to reverse the process very soon, you can be rest assured, it has no harmful effect on the brain. So be rest assured and live in peace.
Let me know if you need more clarifications.
Regards
No harm caused...
Detailed Answer:
Well, I shall try explaining...
Blood pressure, heart rate as well as blood gas levels change with breathing. These changes are quite natural and physiological. When an individual hold breath, there is marginal drop in heart rate as well as rise in blood carbondioxide level. Blood pressure may also drop as the individual continues to voluntarily hold breathe. Both lower heart rate as well as blood pressure reduced brain circulation. Increased carbondioxide also leads to reduced consciousness. All of these factors together combined may lead to near fainting - loss of consciousness.
Hyperventilation has a different set of mechanism. You breath hard and fast during hyperventilation. This hyperventilation drives away cardondioxide from blood. We require enough amount of blood carbondioxide to keep the ventilation (breathing) driving. And thus carbondioxide flush away creates sense of suffocation without the drive to breathe.
I am sorry, if the above description is confusing. However these physiological changes with respect to heart rate, blood pressure, carbondioxide level and so on are quite complex and not easily understandable.
Though the set of physiological changes are complex and difficult to digest, the fact remains. You had those features as well as near fainting spell as a result of body physiology. Nothing pathological about it. And as the body is able to reverse the process very soon, you can be rest assured, it has no harmful effect on the brain. So be rest assured and live in peace.
Let me know if you need more clarifications.
Regards
Note: For further queries related to coronary artery disease and prevention, click here.
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Answered by
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