Heart muscle

[Wolf359]

Originally Posted by javacontour
This just seems obvious. Pumping is not linear to heart rate. That's how I figured it, but I don't have any data to point to how much efficiency is lost as heart rate rises.

Originally Posted by spasm3
Originally Posted by Ws6


As rate increases, efficiency decreases. Especially once you lose the atrial kick.


That, and as heart rate goes up, the diastolic filling period is what gets shortened. Less filling time is less volume in the chamber= less output.



At a certain point it turns into a tachycardia and you don't get any efficiency.

 

[CR94]

Originally Posted by ZeeOSix
^^^ I must be coming down with CV19 ... an average continuous output of 1.13 watts is correct. That equates to 27.18 W-hr in a day. Was getting it bass ackwards, lol.
Thanks for the retraction.

You had the 27.18 watt-hours correct the first time, other than omitting the "in a day." Multiplying by 24 next instead of dividing by 24 resulted in being off by a factor of 24².

Whether we believe the assumption of 2.5 billion joules per 70 years is another matter.

 

[CR94]

Originally Posted by spasm3
Originally Posted by Ws6
As rate increases, efficiency decreases. Especially once you lose the atrial kick.
That, and as heart rate goes up, the diastolic filling period is what gets shortened. Less filling time is less volume in the chamber= less output.
So it's not a positive-displacement pump...

 

[Ws6]

Originally Posted by javacontour
This just seems obvious. Pumping is not linear to heart rate. That's how I figured it, but I don't have any data to point to how much efficiency is lost as heart rate rises.

Originally Posted by spasm3
Originally Posted by Ws6


As rate increases, efficiency decreases. Especially once you lose the atrial kick.


That, and as heart rate goes up, the diastolic filling period is what gets shortened. Less filling time is less volume in the chamber= less output.


Atrial kick is worth about 25%, stroke volume will decrease based on filling time as well, but I am not sure what equation this would be to model rate vs. fill volume, and also suspect it to be nonlinear.

*25% is the number we were taught in school. 10% is about what it is at rest, and 40% is about the loss when exercising, and I'm guessing 25% came from some arbitrary average of uncontrolled afib or something that some egghead decided was the figure to be taught.

 

[Ws6]

Originally Posted by Wolf359
Originally Posted by javacontour
This just seems obvious. Pumping is not linear to heart rate. That's how I figured it, but I don't have any data to point to how much efficiency is lost as heart rate rises.

Originally Posted by spasm3
Originally Posted by Ws6


As rate increases, efficiency decreases. Especially once you lose the atrial kick.


That, and as heart rate goes up, the diastolic filling period is what gets shortened. Less filling time is less volume in the chamber= less output.



At a certain point it turns into a tachycardia and you don't get any efficiency.

Sinus tachycardia is relatively efficient, its SVT that sees a big drop.

 

[ZeeOSix]

Originally Posted by CR94
Originally Posted by spasm3
Originally Posted by Ws6
As rate increases, efficiency decreases. Especially once you lose the atrial kick.
That, and as heart rate goes up, the diastolic filling period is what gets shortened. Less filling time is less volume in the chamber= less output.

So it's not a positive-displacement pump...


It is a PD pump, but the displacement volume and pumping efficiency can change depending on conditions. So therefore, a "variable displacement" PD pump. The amount the heart muscle contracts can effect the output volume.

https://www.me.psu.edu/cimbala/me320web_Spring_2015/pdf/Pumps_lecture.pdf

https://www.quora.com/What-mechanical-pump-can-the-human-heart-be-compared-to

Ejection Fraction is basically a pumping performance/efficiency spec to measure hearth health.

https://www.barnesjewish.org/Medica...c-Arrest/Understanding-Ejection-Fraction

 

[Ws6]

Originally Posted by ZeeOSix
Originally Posted by CR94
Originally Posted by spasm3
Originally Posted by Ws6
As rate increases, efficiency decreases. Especially once you lose the atrial kick.
That, and as heart rate goes up, the diastolic filling period is what gets shortened. Less filling time is less volume in the chamber= less output.

So it's not a positive-displacement pump...


It is a PD pump, but the displacement volume and pumping efficiency can change depending on conditions. So therefore, a "variable displacement" PD pump. The amount the heart muscle contracts can effect the output volume.

https://www.me.psu.edu/cimbala/me320web_Spring_2015/pdf/Pumps_lecture.pdf

https://www.quora.com/What-mechanical-pump-can-the-human-heart-be-compared-to

Ejection Fraction is basically a pumping performance/efficiency spec to measure hearth health.

https://www.barnesjewish.org/Medica...c-Arrest/Understanding-Ejection-Fraction


Also consider the rest of the human being, starting with the lungs. Cardiopulmonary is a word for a reason.