mjl1717
Forum Hero
Topics: 956
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I think of isovolumetric contraction as consuming the greatest energy,vol is equivalent to EDV and mitral and aortic valves are closed,Ventricular pressue is increasing. opening of aortic valve terminates isovolumetric contraction and begins ejection phase. Hope this helps
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| mano
Forum Senior
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contactility increases>>>EDV deacreases>>>loop shifts left
contactility decreases>>>EDV increases>>>loop shifts right
hope it helps
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| Ouli Maty
Forum Elite
Topics: 33
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We can actually work with the curb.
The p-v loop represent how the heart develop pressure or force of contraction ( y axis) during the cardiac cycle when the volume of blood varies (x axis). It depends meanly on preload and contractility.Those two parameters work in opposite directions; when one decrease, the other one increase, vice versa . Except in heavy exercise...
We can deduct preload and afterload from the curb using some indices.
-preload (if you project the vertical line that represent the isovol contraction on the x axis, you have the EDV which can be used as an indice of preload.If you increase preload, EDV increases, shift to the right.
- afterload ( use Peak left ventric pressure as an indice after projecting the upper horizontal line on the y axis). If contractility increases, Peak pressure increases , shift to the left.
Hope it is not confusing. But practicing on the curb can really help.
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