Exam 1 - Lecture II (P/V Loops, Carl Wiggers Diagram) Flashcards
Is the heart capable of filling >120cc?
Yes.
This will produce greater force of contraction and stroke volume.
Slide 39 - PPT 1
What is afterload and what is the normal #?
The pressure the LV must overcome to open the aortic valve & eject blood.
80mmHg
Slide 40 - PPT 1
What should ESV be?
EDV?
Stroke volume?
ESV: 50cc
EDV: 120cc
SV : 70cc
What opens the mitral valve?
& what is this pressure, typically?
⬆ atrial pressure (preload) over the ⬇ ventricle pressure
Usually less than 10mmHg.
Slide 40 - PPT 1
How do valves function?
On a pressure gradients.
Difference in pressure will open valves (can produce the opposite if the pressure are flipped)
13:30
In order to have work, you must have movement. What type of external work does the heart use?
(EW depicted in the picture)
Pressure/volume or volume/pressure work.
The combo of the pressure it builds AND the volume moved = external work. (This area can change as the variables change)
Movement, in the heart, is produced by the build up of pressure.
14:20
What is the sudden ‘blip’ seen @ 110cc?
Atrial kick - this adds an additional 10cc’s of volume and some pressure.
17:20
When is the ‘atria contraction/kick’ most important?
What % did Schmidt say it contributed to our cardiac function?
When we are sick.
~20-25%
Healthy hearts: 5-10%
18:50
What other element does the Carl Wiggers Diagram provide along with pressure and volume?
Time. (in seconds)
20:50
In a resting heart, do we spend more time filling or ejecting?
Filling.
22:40
If you increase HR, what happens to your filling time?
It would decrease.
22:55
Identify 4, 5 & 6.
4: Aortic pressure
5: atrial pressure
6: ventricular pressure - notice the low pressure at the beginning
23:30
What is happening at ‘E”?
Which Phase is ending?
Identify C.
Systole (starts at first bar)
Phase I (Filling) is ending
AV valves closing.
24:40
Identify A.
Which Phase is ending at ‘A’?
A: aortic valve opens
Phase II (Isovolumetric contraction)
25:15
When the intraventricular pressure exceeds the pressure in the aorta, what happens? Which phase begins? What is the pressure this happens at?
The aortic valve opens!
Phase III (ejection) begins
80mmHg
25:40
Phase III (Ejection) can be broken into 3 sections.
What section ejects the most SV?
What can this be referred to as? What is the %?
The first 1/3.
“Rapid Ejection”
70%
27:20
If the SV is 70cc, how many cc’s get ejected during ‘rapid ejection’?
~49cc
(70% of 70cc = 49)
*rapid ejection is the first 1/3 of Phase III (ejection)
27:35
Identify 7.
What happens to it during Phase II? Why?
Ventricular volume.
It flatlines, bc all valves are closed and volume shouldn’t be changed.
28:00
What is happening at ‘B’? Why?
What Phase starts there? What is the pressure?
B: Aortic valve closes
Bc aortic pressure is higher than ventricular.
Phase IV starts! ~100mmHg
Identify ‘D’.
What Phase begins here?
Why does this happen?
D: AV valves open.
Phase I (filling) begins…again!
Bc the pressure in the atria (notice the dotted line) exceeds the pressure in the ventricle (red line).
31:30
What phase does systole begin? End?
Begins: Phase II
Ends: “the end of Phase III” -schmidt
32:40
Diastole starts at the end of Phase ___. The vast majority is filling of the _______ except at the very beginning, when the _____ is being filled before the AV valves open.
IV, ventricles, atria
33:00
Phase I (filling) is divided into 3 parts.
What is the first 1/3 referred to as and how much volume is added?
Part 2?
Part 3?
‘Rapid Filling’, 50cc
10cc
10cc
34:10
Atria pressures are usually less than ___ throughout the entire cardiac cycle.
10
36:00
Identify 1, 2 & 3.
Explain why they happen and how they causes increases in CVP.
1: ‘a wave’ - atrial contraction/kick, increases CVP bc there are no valves btwn the RA and the great veins.
2: ‘c wave’ - ventricle contraction places pressure on AV valves & they ‘bow’ out, increasing CVP
3: ‘v wave’ - from increased pressure in atria from filling, steadily increasing CVP
These are referred to as the ‘Basic CVP’ waveforms by Schmidt.
37:00
________ events must precede ________ events in the heart to generate force. The ___ wave happens prior to the CVP and volume spikes in Phase I.
Electrical, mechanical
P wave
40:15
Identify 9.
Identify G, H, I.
9: Phonocardiogram
G: 1st Heartsound
H: 2nd
I: 3rd
What makes the 1st heart sound? Why is there reverberation?
The 2nd?
3rd?
Why is the 2nd heart sound much shorter than the 1st?
1st: AV valves closure
*specifically the vibration from the leaflets & the cordae tendineae cause the reverberation
2nd: Aortic valve closure
3rd: end of ventricular ‘Rapid Filling’ (not from a valve!)
The aortic valve is ‘meatier’/thicker & doesn’t vibrate as long.
42:00
Pictured is a diagram of the left heart. If we used the right heart we would see _______ ventricular pressures, _____ _____ pressures instead of aortic and ______ volumes.
Lower, pulmonary artery, similar
44:00
What are the two main parts of the circulatory system that can give us information on cardiac function and CO?
Blood vessels connected to heart (venous return)
& pumping effectiveness of the heart (contractility).
44:30
What 2 things do blood vessels dictate?
Heart ejection = CO
Venous return to heart
45:20
In order to maintain a CO of 5L we need a venous return (VR) of 5L. T/F?
True.
48:25
What does this curve tell us?
It is a venous return curve. It is one part of the CO/VR curves. It depicts the relationship btwn the RAP and venous return to the heart.
46:35
IF we have a completely healthy CV system, RAP should be ____. CO should be _____.
Zero.
5L/min
48:00
We previously learned the ΔP of the systemic circulation was 100-0 mmHg.
What is it actually?
Why?
7 - 0 mmHg
Because the majority of our volume is held within the veins, and that is at lower pressures. The average or Psf = + 7mmHg
53:30
If my RAP is +7, & I have no other compensation from my CV system, what is my CO?
Why?
0L/min.
Because my Psf is 7 and my RAP is 7. ΔP = 0
7-7=0 (No CO)
56:30
What is a reason RAP may increase?
(Hint: Not from systemic stimulation or ⬆ venous return.)
Bad pump (HF)
52:20
As RAP becomes positive, VR ⬇ .
T/F?
True!
57:00
What two things determine Psf?
- Tone of the vessels (ANS tone)
- How full the system is (indirectly impacts the tone)
58:00
Your RAP went from 0 to -2. What effects would you see on your VR? Why?
⬆ VR.
The negative pressures widen your ΔP and create a vacuum that would suck more blood to the heart.
60:00
What are the upper and lower RAP limits of the ‘transitional zone’ on the VR curve?
What is the ‘plateau phase’? And why does it occur?
-4 to 0
Plateau phase: -4 to -8
If we have a really negative RAP (produced by the heart bc it is pumping really hard) and no other changes, there is a limit the heart can fill using this ‘vacuum method’.
The large veins have the capacity to collapse if their internal pressure gets too negative.
60:30
If the CV system is not coordinated (pumping & VR) CO is limited.
True or False?
True.
CO is limited to 6L/min.
If the heart starts pumping really hard & out of coordination with VR, this will cause unbalance
62:00
If we cut filling pressure (VR) in half (to +3.5), this will ⬆ / ⬇ the amount of blood returned to the heart to approximately ____ and CO will ________.
Decrease, 4L/min, decrease.
65:40
If you increase Psf to 14mmHg, what would the normal venous return be at a normal RAP?
10L/min
78:00
The majority of the Psf is maintained in the arteries via tone and volume.
True or False?
False!
It is maintained in the veins. (Via tone and volume)
84:50
The periphery vessels feed the heart in the thorax.
Aside from Psf, what other pressure do we need to consider for VR and filling?
Thoracic pressure.
87:00
According to Lange, what is the normal CVP/RAP?
CVP/RAP: 2mmHg = 5L/min VR
(Schmidt said it’s alright to use this # as well)
89:00
What does this curve show us?
Cardiac Output curve of each ventricle (2 hearts) in relation to atrial pressure.
90:30
What is the normal left atrial pressure (LAP)?
Why does the RV operate at lower pressures?
LAP: 2 (notice LV CO at 2mmHg)
The RV pumps against a much lower pulmonary circulation vs. the LV that pumps against the systemic.
91:30
An increase in VR causes an ______ in atrial pressure and ______ in pumping effectiveness. This is the basis of ________ forces.
Increase, increase, Starling
92:45
A decrease in atrial pressure will have a dramatic decrease in VR and CO (with no outside compensation).
True or False?
True!
*Notice the steep decline w/ just a small decrease in atrial pressure…
What is the max CO the heart (on its own) can eject?
13L/min
95:50
What is max CO the heart can eject with max SNS stimulation?
25-30L/min
*elite athletes can have a max ~40L/min 🚴🏼♂️
96:40
Which waves represent a hypoeffective heart or a reduction in contractility?
Which way do they shift & why?
Green & yellow lines. (98:00)
You see a Right shift in order to maintain a CO of 5L/min, they need a higher RAP. (101:20)
The point of intersect can tell us what?
Status of the system.
What do the red lines represent as opposed to the black?
Red: Healthy, exercising heart.
Black: normal resting heart
*it is important for them to be together in order to maintain effective CO.
106:40
112:40
In the exercising heart, just a small ⬆ in _____ allows for a LARGE increase in CO.
RAP
106:50
If we only stimulate the heart and keep VR normal, how much ⬆ in CO will you see?
If we ⬆ VR & keep contractility the same, what happens to CO?
Not a very significant increase.
CO is limited to VR (via tone, volume) (107:30)
CVP & CO increase significantly to about 8mmHg and 13L/min.
(108:40)
With no outside compensation, why does RAP increase so much as more and more volume is returned?
The hearts CO caps out at 13L/min with no outside compensation. So with more VR, you will start to see higher and higher pressures from back up.
110:00
From the green line down, you have decreased sympathetic tone.
What do you think the red line represents? Why?
A failing heart or Heart Failure
Bc the right shift portrays a normal RAP (0mmHg) with very limited CO…and bc Schmidt said it was. ;)
114:20
What is the difference btwn systemic filling pressure (Psf) and circulatory filling pressure?
The circulatory filling pressure also includes pulmonary circ. 🫁
The systemic is depicted to us by the picture on this slide and doesnt include the lungs.
If you inhibit SNS activity with a normal amount of blood, what mean circulatory filling pressure would it produce?
What would lower volumes do to our filling pressure?
~3.5 mmHg (about half of normal)
Lower volume = lower pressure
117:00
If we have a ⬇ volume, to maintain normal filling pressures, we would need an ______ in SNS activity.
If we have ⬆ volume, we would need _______ SNS activity to achieve normal filling pressures.
Increase
Decrease
118:00
What does RVR stand for and what is it?
Resistance to Venous Return
How easy it will be to get blood back to the heart in relation to SVR.
(arteries > veins > heart)
120:00
An increase in SVR will decrease RVR.
True or False?
False.
An increase in SVR (‘the choke point’) will cause an increase in RVR making it more difficult for blood to return to the venous circulation and heart.
122:00
An increase in RVR will do what to the slope and VR?
Shift it down to a lower slope lowering VR.
*think of it like a pathway
“Not something we focus on but I do have to explain it to you…for VR, we’re focused on the change in filling pressures bc it is something you can control via volume or pressers…” -Schmidt
122:30
What is the ‘best’ thing you can do to get a presser to help you with BP?
Increase VR to help the heart produce the pressure you need.
Meds are great but are we getting enough O2 to the tissues?? - most important.
*think about your patient’s poor fingers and toes maxed out on pressers. 🧟♂️
124:00
