Lecture 4- Wiggers diagram

Question 1

outlien the 7 phases of cardiac cycle

Answer 1

1) Atrial contraction
2) Isovolumetric contraction
3) Rapid ejection

4) Reduced ejection
5) Isovolumetric relaxation

6) Rapid filling
7) Reduced filling

Question 2

wiggers diagram

Answer 2

In the Wiggers diagram, the X-axis is used to plot time, while the Y-axis contains all of the following on a single grid:

• Blood pressure
  
  • Aortic pressure
  • Ventricular pressure
  • Atrial pressure
  • Ventricular volume
• Electrocardiogram
• Arterial flow (optional)
• Heart sounds (optional)

Question 3

when does Phase 1: Atria contraction begin

Answer 3

half way through diastole

Question 4

Phase 1: atria contraction

• left atrial pressure

Answer 4

atrial pressure rises due to atrial systole

called the A wave

Question 5

Phase 1: Atria contraction

• ECG

Answer 5

Can be detected on the ECG as the P wave

Question 6

Phase 1: Atria contraction

• valves

Answer 6

both mitral and tricuspid valves are open during atrial contraction

Question 7

Phase 1: Atria contraction

• left ventricular volume

Answer 7

Volume curve shows increase in volume in ventricle as atria contracts

Question 8

Body can survive without atria ‘kick’ e.g. atrial fibrillation- how much ventircular volume does Phase 1: Atria contraction give

Answer 8

Gives final 10% of ventricles volume

Question 9

at the end of phase 1

Answer 9

venticular volumes are maximal- this is termed the end-diastolic volume (EDV)

around 120 ml

Question 11

what is phase 2

Answer 11

Isovolumetric contraction

Question 12

what does Isovolumetric contraction mean

Answer 12

When the ventricles start to contract

(iso-same volume)

(valves not open so blood doesn’t move and volume doesn’t change)

Question 13

Phase 2: Isovolumetric contraction

• left ventricular pressure

Answer 13

Rapid rise of pressure within the ventricle as they contract

Question 14

Phase 2: Isovolumetric contraction

• valves

Answer 14

Shortly into contraction phase the pressure in the ventricle will exceed the atria—> valves will close between the A-V

• triscupid and mitral valves are close

Question 15

Phase 2: Isovolumetric contraction

• left atrial pressure

Answer 15

As the mitral valve closes - C wave

Question 16

Phase 2: Isovolumetric contraction

• left ventricular volume

Answer 16

No change in ventricle volume - valves closed (isovolumetric)

Question 17

Phase 2: Isovolumetric contraction

• ECG

Answer 17

QRS complex in ECG signifies onset of ventricular depolarisation

Question 18

Phase 2: Isovolumetric contraction

• heart sound

Answer 18

Closure of the mitral and tricuspid valves results in the first heart sound (S1)- lub of ‘lub dub’

Question 20

phase 3

Answer 20

rapid ejection

Question 21

Phase 3: Rapid ejection

• valves and aortic pressure

Answer 21

Ejection begins when the intraventricular pressure exceeds the pressuring within the aorta- aortic valve to open

• mitral closed
• aortic open

Question 22

Phase 3: Rapid ejection

• atrial pressure

Answer 22

Atrial pressure initially decreases as the atrial base is pulled downward as ventricle contracts – X descent

Question 23

Phase 3: Rapid ejection

• left ventricular volume

Answer 23

Rapid decrease in ventricular volume as blood is ejected into aorta

Question 24

phase 4

Answer 24

reduced ejection

Question 25

Phase 4: Reduced ejection * left ventricular pressure

Answer 25

- Decreases Repolarisation of ventricles leads to a decline in tension and the rate of ejection begins to fall

Question 26

Phase 4: Reduced ejection * valves

Answer 26

* mitral- closed * aortic- open

Question 27

Phase 4: Reduced ejection * atrial pressure

Answer 27

Atrial pressure gradually rises due to the constant venous return from the lungs – **V wave**

Question 28

Phase 4: Reduced ejection * ECG

Answer 28

Ventricular repolarisation is depicted by the T-wave on ECG

Question 29

Phase 5

Answer 29

Isovolumetric relaxation

Question 30

Isovolumetric relaxation means

Answer 30

Ventricular relaxation valves closed- volume same

Question 31

Phase 5: Isovolumetric relaxation * valves

Answer 31

When intraventricular pressure falls below aortic pressure there is a brief back flow of blood which causes the aortic valve to close \*mitral also closed\*

Question 32

Phase 5: Isovolumetric relaxation * aortic pressure

Answer 32

Dicrotic notch in aortic pressure curved caused by valve closure

Question 33

Phase 5: Isovolumetric relaxation * ventricular pressure

Answer 33

Although rapid decline in ventricular pressure, volume remains constant since all valves are closed- Isovolumetric reaction

Question 34

Phase 5: Isovolumetric relaxation * ventricular volume

Answer 34

stays the same End systolic volume

Question 35

stroke volume=

Answer 35

EDS-ESV (70-80ml)

Question 36

Phase 5: Isovolumetric relaxation * heart sounds

Answer 36

Closure of aortic pulmonary valve results in the second heart sound (S2)

Question 37

phase 6

Answer 37

rapid filling

Question 38

Phase 6: Rapid filling * left atrial pressure and left ventricular pressure

Answer 38

* Fall in atrial pressure that occurs after opening of mitral valve called Y-descent * When the intraventricular pressure falls below atria pressure, the mitral valve opens and rapid ventricular filling

Question 39

Phase 6: Rapid filling * heart sounds

Answer 39

* Ventricle filling normally silent * However third heart sound (S3) sometime present - in children * Sign of pathology in adults

Question 40

phase 7

Answer 40

reduced filling

Question 41

Phase 7: Reduced filling

Answer 41

* Rate of filling slows down (diastasis) as ventricle reaches its inherent relaxed volume * Further filling is driven by venous pressure * At rest the ventricles are 80% full by the end of phase 7 * Require Phase 1: atrial contraction for final push

Question 42

Phase 7: Reduced filling * valves

Answer 42

mitral- open aortic- closed