Cardiac Function And Venous Return Curves

Question 1

As End Diastolic Volume increases on CO

Answer 1

The CO increase also

Question 2

As EDV increases the, on Venous Return

Answer 2

The Venous Return stays steady and then decreases

Question 3

What determines the Venous Return

Answer 3

The Right Atrial Pressure

The lower the RAP the more venous return

Question 4

Another way of saying CO

Answer 4

ESCPR (End-Systolic-Venous - pressure- relationship):

=CO AND EDV - curve

Question 5

What increases the CO and with the EDV staying the same

Answer 5

Inotropy (contractility) increases, CO increases and EDV stays the same

Question 6

When is the venous return and EDV in equilibrium

Answer 6

At +2mmHg RAP

Question 7

When does venous return stay the same

Answer 7

Any EDV when the RAP is 0mmHg or less

Question 8

Pulmonary resistance goes up, what happens to venous return

Answer 8

Pulmonary HTN —> RV needs more force to push blood out —> RA increases P so blood can go into high P V——> decreases venous return

Question 9

Mean Systemic Filling Pressure

Answer 9

Psf
= P in vasculature when there is no flow
= 7+ mmHG RAP ——> venous return = 0mmHg

Question 10

When does the right amount of venous return occur

Answer 10

At +2mmHg RAP

Question 11

Increased TPR on CO and VR

Answer 11

Decreases both
(Specifically in arterioles and arteries)
*Psf stays the same

Question 12

What happens when TPR decreases

Answer 12

No change in Psf

Increased CO and VR

Question 13

What causes the CO, VR, and Psf to increase all together

Answer 13

1. RAPID BLOOD VOLUME INCREASE
2. Increased venous tone
3. Venoconstriction (unstressed volume)

Question 14

When does the CO = Venous Return

Answer 14

EQUILIBRIUM = +2mmHg RAP*

(CO=+5 L/min, VR= +5 L/min) *

Question 15

RAP in heart failure

Answer 15

RAP increases
CO decreases (SV decreases, more blood left tin V)
Venous Return (+3mmHG)

Question 16

Venous return is controlled more by what N

Answer 16

Alpha 1

Question 17

CO is controlled more by what N

Answer 17

Beta1

Question 18

Higher contractility does what to CO, VR, RAP

Answer 18

RAP decreases (more blood ejected)
CO increases (higher SV and, less blood left in V)
Increased afterload
= 0mmHG RAP, venous return is plateau at 6mmHg

Question 19

Increased Blood Volume causes what to CO,VR, RAP

Answer 19

RAP increases
CO increases
Venous Return = 6mmHg
Contractility stays the same

Question 20

Blood volume increased
CO
RAP
Psf

Answer 20

CO : Increased (13L/min)
RAP : increased (+7mmHg)
Psf : increased to (+16mmHg)

Question 21

Decrease in TPR on
CO, VR
RAP
Psf

Answer 21

Increases CO (reduced afterload), increased VR
*new equilibrium at +2mmHG, (VR and CO = 6mmHG)
RAP STAYS THE SAME
Psf stays the same also (+7)

Question 22

Increased TPR (arteriole constriction, blood stays longer in arteries) on
CO, VR
RAP
Psf

Answer 22

Decreased CO, decreased VR
= * new equilibrium at +2mmHG (both CO and VR are +3L/min)
RAP and Psf stay the same

Question 23

EDV

ESV

Answer 23

Volume in Heart right before contraction

Volume in Heart right after contraction (usually 40%, 120mL-50mL)

Question 24

CO =

Answer 24

CO = SV x HR

SV influenced by myocardial contractility

Question 25

CO is influenced by what 4 things

Answer 25

1. HR 2. Contractility (effecting SV) 3. Preload 4. Afterload

Question 26

What is SV

Answer 26

V ejected by Ventricle each beat | SV = EDV -ESV (usually 70mL)

Question 27

What is the ejection fraction

Answer 27

Fraction of EDV ejected (usually 55%) *efficiency and contractility measured this way* EF = SV/EDV

Question 28

What is Cardiac Output (Q)

Answer 28

TOTAL volume of blood ejected by Ventricle PER MINUTE | CO = SV x HR (usually 5L/min)

Question 29

EDV is usually ESV is usually + what happens in heart here

Answer 29

``` EDV = 120mL (*mitral valve closes after SA node) ESV = 50mL (*right before mitral valve opens) SV= 70mL EF= 58% ```

Question 30

Preload is what

Answer 30

Amount of blood ready to be pumped (EDV) *effected by Venous Return ——> CO = tension of Ventricular wall tension

Question 31

Afterload is what

Answer 31

Force to push blood out (or open valve) LV afterload : effected by aortic P *a little greater then the aortic P, or pulmonary A (for RV) *estimated to = Diastolic Pressure or person

Question 32

Afterload and velocity of myocardial contraction

Answer 32

As afterload increases the velocity of the muscles contracting decreases

Question 33

Diastolic Pressure related to Systolic Pressure | =ESPVR (end systolic pressure volume relationship)

Answer 33

Diastolic P at 110ml - 160mL (in LV) = causes highest systolic pressure and CO * Titin is the ideal stretch here * higher and lower V in LV (and P in Diastolic P) will decrease the systolic P = myosin and actin overlap is not ideal

Question 34

Isometric contraction of V has what inside

Answer 34

``` The EDV (end diastolic volume) * valve opens = afterload pressure (around 80mmHG) ```

Question 35

After SV has been ejected and the aortic valve closes, what happens in the heart

Answer 35

The blood V left in the LV is contestant = isometric relaxation *LV V increases again when mitral valve opens again (when A pressure has increased, and LV pressure has decreased*)

Question 36

ESPVR represents

Answer 36

Contractility | More contractility = peak of ventricular pressure = INCREASED ESP

Question 37

``` Decrease in PRELOAD does what to EDV ESV SV Afterload Contractility ```

Answer 37

``` EDV: decreased ESV : no change SV : decreased Afterload : no change contractility: no change ```

Question 38

``` increase in AFTERLOAD does what to EDV ESV SV Afterload Contractility ```

Answer 38

EDV : no change ESV : increased SV : decreases Contractility : no change

Question 39

4 things causing increased afterload

Answer 39

1. HTN, (increased TPR) 2. Aortic Stenosis 3. Increased blood viscosity 4. Increased intrathoracic Pressure

Question 40

Causes for decrease in AFTERLOAD

Answer 40

1. Hypotension (low TPR) 2. decrease in blood viscosity 3. A fistula (organs causing decrease resistance of blood in arteries)

Question 41

``` Decrease in AFTERLOAD does what to EDV ESV SV Contractility ```

Answer 41

Stays the same Decrease Increase Stays the same

Question 42

``` Increase in CONTRACTILITY does what to EDV ESV SV Afterload ```

Answer 42

``` EDV : no change ESV : decrease SV: increases Afterload : no change * LV pressure at peak increased some ```

Question 43

``` Decrease in CONTRACTILITY does what to EDV ESV SV Afterload ```

Answer 43

``` No change Increase Decrease No change *negative inotropy * LV pressure decreased some at its peak ```