Cardiac Function 1

Question 1

What is a ECG?

Answer 1

• electrocardiogram
• A look at the electrical activity of the heart on the surface of the skin
• Using electrical leads and electrodes – detects synchronicity of electrical signal provides a picture of what is happening

Question 2

How are ECGs useful?

Answer 2

Used clinically to detect abnormalities – collect HR data

Question 3

How do ECGs work?

Answer 3

• Body = conductor
• Currents spread to the surface of the body
• Heart electrical activity = synchronized
• Activity can be detected

Question 4

Name 2 common ECG arrhythmias.

Answer 4

• Tachycardia

- Bradycardia

Question 5

What is tachycardia?

Answer 5

> 100 bpm resting

Question 6

What is bradycardia?

Answer 6

<50 bpm resting

Question 7

What is first degree heart block?

Answer 7

• conduction slowed (AV node)
• PQ segment increased
• delayed contraction of ventricles

Question 8

What is second degree heart block?

Answer 8

• slowed/stopped conduction (AV node)

- the cycle between A-V’s is lost

Question 9

What is third degree heart block?

Answer 9

• no conduction (AV node)

- P wave - QRS independent

Question 10

What is the risk of atrial fibrillation?

Answer 10

increased clot risk

Question 11

What is the risk of ventricular fibrillation?

Answer 11

• serious

- loss of electrical coordination

Question 12

What is the treatment for ventricular fibrillation?

Answer 12

• AED

Question 13

What is PAC?

Answer 13

• premature atrial contraction

- irregular heart beat; exact cause is unknown

Question 14

Name some potential causes of PAC.

Answer 14

• caffeine
• alcohol
• stress
• fatigue sleep disturbances
• medication

Question 15

What is PVC?

Answer 15

• premature ventricular contraction

- “pause in heart rate”

Question 16

Name some potential causes of PVC.

Answer 16

• chemical imbalances
• caffeine
• anxiety/stress
• medication
• drugs/alcohol

Question 17

Heart sounds occur when…

Answer 17

• valves close

- changes in flow

Question 18

What is the first heart sound?

Answer 18

• soft “lubb”

- AV valves close simultaneously

Question 19

What is the second heart sound?

Answer 19

• louder “dupp”

- semilunar valves close simultaneously

Question 20

In phase 1, what valves are open?

Answer 20

• atrioventricular valves are open

- aortic and pulmonary valves are closed

Question 21

The first heart sound occurs when?

Answer 21

phase 2

Question 22

In phase 3, what valves are open?

Answer 22

• atrioventricular valves are closed

- aortic and pulmonary valves are open

Question 23

The second heart sound occurs when?

Answer 23

phase 4

Question 24

What happens during diastole?

Answer 24

• relaxation
• aortic valve closes
• blood is still leaving aorta, so pressure falls
• lowest point = diastolic pressure

Question 25

What happens during systole?

Answer 25

- aortic valve opens - pressure rises rapidly with ejection - highest point = systolic pressure - aortic valve closes: dicrotic notch

Question 26

What happens during phase 1?

Answer 26

- atrial pressure rises slowly with filling of blood - ventricular pressure is low - atrial contraction at end = small increase in ventricular pressure

Question 27

What happens during phase 2?

Answer 27

- start of systole - rapid rise in ventricular pressure - atrial pressure fails

Question 28

What happens during phase 3?

Answer 28

- ventricular pressure falls - no change in volume - atrial pressure falls further until late systole

Question 29

Describe left ventricular pressure/volume in phase 1.

Answer 29

- Ventricular volume increases from 60 mL to 130 mL | - Small pressure increment with filling

Question 30

Describe left ventricular pressure/volume in phase 2.

Answer 30

Volume remains constant; pressure increases dramatically

Question 31

Describe left ventricular pressure/volume in phase 3.

Answer 31

- Volume decreases to 60 mL | - Pressure rises, then falls precipitously

Question 32

Describe left ventricular pressure/volume in phase 4.

Answer 32

Pressure continues to fall

Question 33

What influence do elastic arteries have on blood flow at aorta (an elastic artery)?

Answer 33

- pressure reservoir - stores energy during systole as walls expand - releases energy during diastole as walls recoil inward

Question 34

How does the structure of arteries impact blood flow?

Answer 34

- stored pressure | - continuous blood flow during cardiac cycle

Question 35

Why is the relationship between stored pressure and blood flow important?

Answer 35

aortic pressure maintains blood flow through the entire cardiac cycle

Question 36

What is EDV?

Answer 36

- end diastolic volume - preload - volume of blood in ventricle at the end of diastole

Question 37

What is ESV?

Answer 37

- end systolic volume | - volume of blood in ventricle at the end of systole

Question 38

What is SV?

Answer 38

- stroke volume | - volume of blood ejected from ventricle each cycle

Question 39

SV =

Answer 39

SV = EDV - ESV

Question 40

SV for exercise =

Answer 40

100 - 200 mL

Question 41

What is EF?

Answer 41

- ejection fraction | - fraction of end diastolic volume ejected during a heartbeat

Question 42

EF =

Answer 42

stroke volume/end diastolic volume

Question 43

EF can be used as...

Answer 43

a predictor of disease (CAD), specifically exercise EF

Question 44

EF with exercise can be ...

Answer 44

> 90% in highly conditioned

Question 45

EF with disease can be ...

Answer 45

< 20% at rest

Question 46

Normal EF at rest =

Answer 46

~60% +