Lecture 1-28 (Loops) Flashcards by Shirica Shaw

What are mixed vasodilators? How do they work? Examples

They dilate the arteries, decreasing RVR, and veins, decreasing systemic filling pressure.

Sodium Nitroprusside
Nipride

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Sodium Nitroprusside & Nipride are both ________ and they will fall apart in ______

Nitric oxide donors

sunlight

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In mixed vasodilators, the more prominent effect is seen in the ________

systemic filling pressure

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Nitroglycerin is a __________ and has more effects on the _______ than the __________

Venous dilator

veins

arteries

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What effects does nitroglycerin have on the heart? What pathology is this useful in?

Reduces preload
-reduces metabolic demand

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T/F: We can give nitroglycerin for a big MI

big MI probably wiped out preload. Nitroglycerin will reduce reload even further.

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ACE inhibitors work more specifically on the _______ which ______ afterload

arteries

decrease

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Which vasodilator works ONLY on the arteries? What is its MOA?

hydralazine

unknown

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What type of vasoconstrictor is phenylephrine? What does it mainly work on? How does this effect the heart?

Mixed vasoconstrictor

Bigger effect on the veins = increased preload

increases afterload

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After an MI, the ______ kicks in by doing what?

Nervous system

Increasing sympathetic activity & venous tone (systemic filling pressure)

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Describe cardiac output and R atrial pressure in an MI

CO drops without any compensatory mechanisms.
Max increase sympathetic activity (heart) & increased venous tone/catecholamines (Psf) to increase CO back to 5
Fluid retention increases (Psf) –> catecholamines decreases –> decrease in sympathetic activity (heart) –> R Atrial pressure increases –> CO stays at 5
Fluid retention increases even more (Psf) –> catecholamines decrease –> sympathetic activity returns to normal (heart) –> R atrial pressure increases even more –> CO stays at 5

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After an MI, why do we need sympathetic stimulation to return back to normal or catehcolamines to decrease?

Predisposes to arrhythmias

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What will R atrial pressure be after an MI, when compensatory effects have returned sympathetic activity to normal?

8 mmHg

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What happens when we stand up?

CNS tightens blood vessels to prevent passing out

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During heart failure, SVR _______, Psf _______, volume expansion ________, venous compliance _____

increases
Increases
increases
decreases

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Increasing SVR has what effect on RVR?

Decreases the slope, making it more difficult for blood to return to the heart

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Whats the difference between preload & afterload?

Preload: pressure to fill heart

afterload: pressure heart has to pump against outside of aortic valve

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What happens when afterload is increased?

Its harder to pump blood out the heart

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Where is preload?

Pressure at the end of phase 1
-Pressure where EDV is

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Where is afterload?

Pressure at the end of phase 2
-Pressure where diastolic pressure is & where aortic valve opens (right before it opens)

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How does increasing preload affect the cardiac cycle/curve?

Increase preload –> Increase EDV (filling volume) –> Increase SV –> Increase SBP

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How does decreasing preload affect the cardiac cycle/curve?

decrease preload –> decrease EDV (filling volume) –> decrease SV –> decrease SBP

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How does increasing afterload affect the cardiac cycle/curve?

Increase afterload –> increase time in phase 2 to get to higher diastolic pressure/afterload –> decrease time in phase 3 (ejection) –> aortic valve closes early at higher pressure –> increased SBP –> decrease SV –> increase ESV –> increase HR

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When it’s harder for the heart to pump, we worry about ________

remodeling/hypertropy

With increased afterload and sick patients, we may want to consider ______ the BP if tolerable

dropping

How does decreasing afterload affect the cardiac cycle/curve?

Decrease afterload --> decrease time in phase 2 to get to lower diastolic pressure/afterload --> increase time in phase 3 (ejection) --> aortic valve closes later at lower pressure --> decrease SBP --> increase SV --> decrease ESV --> decrease HR

Increasing afterload ________ the metabolic demands of the heart, and decreasing afterload ________ the metabolic demands of the heart

Increases Decreases

How does increasing contractility affect the cardiac cycle/curve?

Increase contractility --> increase time in phase 3 --> increase SBP --> Increase SV --> aortic valve closes later at higher pressure --> decrease ESV

How does decreasing contractility affect the cardiac cycle/curve?

Decrease contractility --> decrease time in phase 3 --> decrease SBP --> decrease SV --> aortic valve closes earlier at lower pressure --> increase ESV

What type of medication can we use to treat decreased contractility in a heart failure pt after remodeling? Why?

Afterload reducer such as ACE inhibitor or hydralazine Increase phase 3 --> increase SV --> decrease ESV **decreases the metabolic demands of the heart** allowing for a decreased HR

What does the area underneath the cardiac cycle curve represent?

passive tension to fill the heart

What happens to passive tension in HR?

increase dt blood volume retention **This volume for passive filling is needed in these pts for a normal CO**

How does Aortic valve stenosis affect the cardiac cycle/curve?

Increase afterload/diastolic pressure --> increase time in phase 2 to get to higher pressure to open aortic valve --> decrease time in phase 3 (ejection) --> aortic valve closes early at much higher pressure --> increase SBP --> decrease SV --> increase ESV --> increase HR --> increase preload --> increase EDV

What is a hallmark symptom in aortic valve stenosis?

Narrowed PP

In aortic stenosis, the pressure in the L vent has to greatly _________ to open the aortic valve

increase

With aortic stensis, the pressure in the aorta is ________ the ventricle

much lower than in

With aortic stensis, R atria pressure is expected to ______-

increase

Mitral valve stenosis is a ______ problem with the ________ ventricle

Filling Left

How does Mitral valve stenosis affect the cardiac cycle/curve?

Mitral valve stenosis --> Decrease EDV --> decrease SV --> decrease CO --> increase HR

How does the heart compensate for mitral valve stenosis? Where are these changes seen at?

Increase preload increase Psf Increase atrial pressure increase blood volume These increases in pressure & volume are seen in front of the L atria (pulmonary circuit/lungs)

Does L atria pressure increase during Mitral valve stenosis?

Yes

What does severe Mitral valve stenosis require? Why?

Mitral valve replair/replacement to prevent pulm HTN A continued/prolonged high increase in pressure/volume in the pulmonary circuit --> pulmonary HTN --> pulomary edema --> impaired gas exchange **Compensatory effects of mitral valve stenosis to increase CO causes this**

What pathology can severe mitral valve stenosis lead to?

**pulmonary HTN** --> pulmonary edema

What is the pathology of aortic valve insufficiency?

**Regurgitation** Retrograde blood movement when the aorta valve is closed & pressure in aorta is higher than L vent.

In aortic valve insufficiency, during what phases is there the most amount of backflow? Why?

End of phase 4 phase 1 (esp. early part) This is where the aorta pressure is highest & L vent pressure is lowest

When L vent volume is increasing while the aorta is closed, what does this mean?

Aortic insufficiency/regurgitation

In aortic valve insufficiency/regurgitation what is the relevance of phase 1 in the cardiac cycle/curve?

The L ventricle is fillinf from 2 places at once: -L atria during diastole -Aorta from retrograde backflow

How does Aortic valve insufficiency/regurgitation affect the cardiac cycle/curve?

Aortic valve insufficiency/regurgitation --> Increase EDV --> Decrease DBP --> Increase SV --> Increase SBP

What results from Aortic valve insufficiency/regurgitation?

L vent dilation dt increased EDV --> increased problems w/ aortic valve & problem w/ mitral valve dt increase L vent volume

In Aortic valve insufficiency/regurgitation, the PP ______

widens

In Aortic valve insufficiency/regurgitation, during what phases are there retrograde backflow from aorta only? Both aorta and atria?

Phase 4 Phase 1

T/F: Aortic & mitral valve regurgitation have isovolumetric phases

F The volumes are changing in phases 2 & 4

Why is the SV so large in Aortic valve insufficiency/regurgitation?

To make up for all the extra volume dt backflow & atria filling

What is the pathology of Mitral Regurgitation?

Blood is moving from L vent retrograde into L atria dt leaky valve

In Mitral Regurgitation, when is blood more likely to move retrograde into the L atria? What phases are these? What happens to ventricular volume?

When L vent pressure is higher than L atria pressure Phase 2 Phase 3 Phase 4 Decreasing

In Mitral Regurgitation, what is happening during systole?

Systole is phase 3. The mitral valve is closed --> blood is leaking back into the L atria from the L vent. --> volume in L vent decreasing --> decrease in SBP

How does Mitral valve regurgitation affect the cardiac cycle/curve?

Mitral valve regurgitation --> increase EDV --> increased preload --> decreased SV --> decreased SBP --> decreased ESV

In Mitral valve regurgitation the preload is _________

increased

Lecture 1-28 (Loops) Flashcards

Cardiac (Loops)