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Flashcards in Cardiac Function Deck (19)
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1

How does an increase in the preload affect the stroke volume?

It will increase the stroke volume.

2

How does an increase in the after load affect the stroke volume?

It will decrease the stroke volume.

3

How does and increase in the contractility affect the stroke volume?

It will increase the stroke volume.

4

What volumes in the heart change as a result of increasing the preload?

End Diastolic Volume is increased as the heart fills up more

5

What volumes in the heart change as a result of increasing the after load?

End Systolic Volume is increased as the heart pumps out less blood against the higher pressure

6

What volumes in the heart change as a result of increasing the contractility?

End Systolic Volume is decreased as the ejection velocity is increased due to the increased contractile force of the heart.

7

What is systolic heart failure and what is it caused by?

Systolic heart failure is caused by a decrease in the ventricular contractility of the heart which results in an increased EDV but also an increased ESV as well due to weaker contraction force.

8

What is diastolic heart failure and what is it caused by?

Diastolic heart failure is caused by a decrease in the ventricular compliance as the heart becomes too stiff, the EDV is much lower as it cannot be filled normally. The ESV remains the same, however, stroke volume has been decreased.

9

What is the ejection fraction?

It is the fraction of blood ejected in one stroke of the heart.

10

How is ejection fraction calculated?

[(EDV -ESV)/EDV] * 100

11

What is the normal ejection fraction?

60%

12

What does an increase in end diastolic pressure affect and how does it affect it?

It affects the preload as it decreases ventricular filling.

13

What does a decrease in the ventricular filling time affect and how does it affect it?

Preload. It decreases ventricular filling.

14

What does a decrease in the ventricular compliance affect and how does it affect it?

Preload. It decreases ventricular filling.

15

What does atrial fibrillation affect and how does it affect it?

It affects the preload by decreasing ventricular filling.

16

What are some factors that can affect the contractility of the heart?

Sympathetics
Drugs (digitalis)
Diseases of the heart

17

What does an increase in the aortic pressure affect and how does it affect it?

Afterload. It decreases the stroke volume of the heart.

18

What does an aortic stenosis affect?

Afterload. It decreases the stroke volume of the heart.

19

What does a dilated heart affect?

Afterload. It increases the wall tension which will also raise the after load on the heart.

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