Cardiology Part 2

Question 1

On a cardiac function curve, What represents the Y and X axis and the Slope?
-Which variables are independent and/or dependent?

Answer 1

-Y axis: Cardiac output (dependent)
-X Axis: Right atrial pressure (independent variable)
-Slope: Defined by contractility, afterload, and heart rate

Question 2

On a cardiac function curve, What occurs to the curve if Inotropy or Heart rate decreases?

Answer 2

Causes a rightward shift (depressed curve)

Question 3

On a cardiac function curve, What occurs to the curve if Inotropy increases?

Answer 3

Causes a leftward shift

Question 4

On a cardiac function curve, ___________ is inversely proportional to CO

Answer 4

TPR (afterload)

Question 5

On a cardiac function curve, if there is increased TPR, what will the resulting CO be?

Answer 5

Decreased CO

Question 6

On a cardiac function curve, what will an increased afterload or decreased afterload do?
-Include the contrast with contractility

Answer 6

Left shift: decreased afterload (or increased contractility)
Right shift: Increased afterload (or decreased contractility)

Question 7

On a venous return curve, What is the X and Y axis, which are independent or dependent, and what is the value of the slope?

Answer 7

X axis: Right atrial pressure (dependent)
Y axis: Cardiac output
Slope: Defined by TPR

Question 8

On a venous return curve, what is the X and Y intercept?

Answer 8

Defined by venous compliance and total blood volume

Question 9

On a venous return curve, What is the CO of the X intercept?
-What is the X intercept?

Answer 9

CO = 0;
X intercept is the mean systemic filling pressure (MSFP)

Question 10

What is the surrogate marker of the central venous pressure?

Answer 10

Right atrial pressure (RAP)

Question 11

On a venous return curve, What causes the up or down shifts?

Answer 11

Shift up: Decreased TPR or Increased CO
Shift down: Decreased CO or Increased TPR

Question 12

On a venous return curve, what is the relation between CO and RAP?

Answer 12

Inversely proportional (Increased CO = Decreased TPR)

Question 13

On a combined cardiac and venous return curve, What is the intersection and the separate variables of this graph?

Answer 13

Intersection: Steady state operating target for RAP and CO
Slope of cardiac f(x) curve: Effected by inotropy, HR, and afterload
Slope of venous return: Effected by TPR
X intercept of Venous return: CO and Venous compliance

Question 14

When Venous compliance and cardiac function curve are equal, this is known as?

Answer 14

Steady State

Question 15

What is the effect of the following on the Cardiac Function curve:
-Inotropy
-Heart rate
-Afterload

Answer 15

Inotropy: directly proportional to (Inotropy goes up, as does curve)
Heart rate: Directly proportional to (Heart rate goes up, as does curve)
Afterload: Directly proportional to (Afterload goes up, as does curve)

Question 16

What is the effect of the slope of the venous curve if TPR goes up or down?

Answer 16

Increased TPR: Slope goes down
Decreased TPR: Slope goes up

Question 17

The venous curve is __________ proportional to TPR?

Answer 17

Inversely proportional

Question 18

On a combined cardiac and venous return curve, The X intercepts effected of these variables: (What makes the Intercept go up or down)
-CO
-Venous compliance

Answer 18

Up: Increased CO, decreased VC
Down: Decreased CO, increased VC

Question 19

What does exercise do to the Slopes of the combined curves?

Answer 19

It increases all of them

Question 20

In Acute Hemorrhage, What is the effect of the following:
-Disruption:
-Cardiac F(x) Curve:
-Venous return curve:
-Steady State:

Answer 20

-Disruption: Causing decreased blood volume
-Cardiac F(x) Curve: No Change
-Venous return curve: X int. Shifts left
-Steady State: Shifted downward and to the left

Question 21

With IV fluids, What is the effect of the following:
-Disruption:
-Cardiac F(x) Curve:
-Venous return curve:
-Steady State:

Answer 21

-Disruption: Increased blood volume (CO)
-Cardiac F(x) Curve: No change
-Venous return curve: X int. shifts to the right
-Steady State: Shifted upward and to the right

Question 22

In chronic systolic heart failure, What is the effect of the following:
-Disruption:
-Cardiac F(x) Curve:
-Venous return curve:
-Steady State:

Answer 22

-Disruption: Decreased inotropy
-Cardiac F(x) Curve: Decreased Slope
-Venous return curve: Slope decreases, X int. Shifts right
-Steady State: Shifted downward and to the right

Question 23

With Digoxin, what is the effect of the following:
-Disruption:
-Cardiac F(x) Curve:
-Venous return curve:
-Steady State:

Answer 23

-Disruption: Increased Inotropy
-Cardiac F(x) Curve: Increased Slope
-Venous return curve: Unchanged
-Steady State: Shifted upward and to the left

Question 24

With phenylephrine, what is the effect of the following:
-Disruption:
-Cardiac F(x) Curve:
-Venous return curve:
-Steady State:

Answer 24

-Disruption: Increased TPR (a1-agonist)
-Cardiac F(x) Curve: Decreased slope
-Venous return curve: Decreased slope, x-int. unchanged generally
-Steady State: shifted downward

Question 25

With hydralazine, what is the effect of the following:
-Disruption:
-Cardiac F(x) Curve:
-Venous return curve:
-Steady State:

Answer 25

-Disruption: Decreased afterload (TPR)
-Cardiac F(x) Curve: Elevated slope
-Venous return curve: Elevated slope, X int. unchanged
-Steady State: Shifted upward

Question 26

When interpreting combined cardiac function/venous return curves, what should be focused on?

Answer 26

Focus on a single primary disruption

Question 27

AV fistulas have what effect on TPR?
-How does this effect the steady state?
-How does this effect the slopes of the curves?

Answer 27

Decreases TPR
-Elevates the SS
- Increases both slopes of curves