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35 Cards in this Set
- Front
- Back
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what is the definition of contractility?
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this is the ability of the heart to do work at any given fiber length
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what is the definition of preload?
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this is the change in end-diastolic fiber length
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what is the definition of afterload?
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this is arterial pressure, or downstream pressure on the heart
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what 3 things does the SNS stiumlation do, regarding cardiac performance?
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this increases SV at given EDV
increases ejection fraction (EF= SV/EDV ) positive ionotropic effect (NE stiumulates B1 receptors) Increases the RATE of contraction and RATE of relaxation (maintains filling time) |
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what does increasing contractility (via SNS) do?
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this increases ejection fraction, and lowers ESV
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What has an effect on ESV?
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the afterload, and the contractility (both affect the ease of blood to leave the heart)
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what is the normal ration of SV to EDV?
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50-75%
less than 40 is bad...mmk? |
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How does heart rate affect cardiac performance?
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Treppe- A faster heart rate leads to Ca2+ accumulation, which increases contractility (SV, and EF increase)
CO=HR*SV....affected only below 50 or above 150BPM |
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what is the definition of contractility?
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this is the ability of the heart to do work at any given fiber length
|
|
|
what is the definition of preload?
|
this is the change in end-diastolic fiber length
|
|
|
what is the definition of afterload?
|
this is arterial pressure, or downstream pressure on the heart
|
|
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what 3 things does the SNS stiumlation do, regarding cardiac performance?
|
this increases SV at given EDV
increases ejection fraction (EF= SV/EDV ) positive ionotropic effect (NE stiumulates B1 receptors) Increases the RATE of contraction and RATE of relaxation (maintains filling time) |
|
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what does increasing contractility (via SNS) do?
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this increases ejection fraction, and lowers ESV
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What has an effect on ESV?
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the afterload, and the contractility (both affect the ease of blood to leave the heart)
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what is the normal ration of SV to EDV?
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50-75%
less than 40 is bad...mmk? |
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How does heart rate affect cardiac performance?
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Treppe- A faster heart rate leads to Ca2+ accumulation, which increases contractility (SV, and EF increase)
CO=HR*SV....affected only below 50 or above 150BPM |
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What does treppe do to maintain cardiac output?
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this increases the Ca2+ available for release on subsequent beats, which means stronger contractions and greater cardiac output (or rather, maintained)
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what does increased preload do to the PV loop?
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this increases EDV
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what does increased afterload do to the PV loop?
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this increases systolic pressure, and increasse end systolic volume
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what are the two equations for LVSW?
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LVSW= SV * LVPP
LVSW= SV * MAP MAP= DP + pp/3 |
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what is the equation to find LVMW? (ventricular minute work)
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LVMW= SV*MAP*HR
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what is the equation for Stroke volume?
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SV=EDV-ESV
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What is the equation for ejection fraction
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EF=SV/EDV * 100%
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what is the equation for mean aortic presssure?
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MAP= DP+ 1/3(PP)
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what is the equation for cardiac output?
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CO= SV * HR
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what is the equation for Cardiac index?
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CI= CO/SA in m^2
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What is the equation for LVSW
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LVSQ= MAP*SV
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What is the equation for Left ventricular work index?
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LVWI= LVSW/SA
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What is the fick method? and what is its equation?
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This is a measure of Cardiac output
measure by CO= O2 consumption/(arterial O2-Venous O2) |
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where is the venous O2 level checked using the Fick method?
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this is checked in the Pulmonary artery via catheter, (or maybe the RV)
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How much more work does the LV do, as compared to the RV?
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6-7X more
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what is the resting metabolic rate?
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4.8-6ml/gm/h
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whats the efficiency of the myocardium?
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5-15%
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how does efficiency change with exercise?
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it improves
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Which requires more energy, to increase volume work? or pressure work?
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pressure work requires more energy
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