Cardiac Cycle

Question 1

What is basic overview of the cardiac cycle blood flow through the heart?

Answer 1

1. Venous return great veins (SVC, IVC)-right atrium
2. Tricuspid valve
3. Right ventricle
4. Pulmonary semilunar valve
5. Pulmonary arteries
6. Lung circulation
7. Pulmonary veins
8. Left atrium
9. Bicuspid (mitral) valve
10. Left ventricle
11. Aortic semilunar valve
12. Aorta
13. Systemic circulation

Question 2

What is the chamber and volume change like in ventricular filling/atria contraction?

Answer 2

Higher pressure in atria > ventricles
tri/bi valves open - blood enters ventricles
Atrial contraction – extra filling

Question 3

What is the chamber and volume change like in isovolumetric contraction?

Answer 3

Higher pressure in ventricles >
atria so tri/bi valves close
Closed ventricle

Question 4

What is the chamber and volume change like in ejection?

Answer 4

Higher pressure in ventricles
> aorta/pulmonary artery
Valves open
Blood flows out of heart
Blood enters atria

Question 5

What is the chamber and volume change like in isovolumetric relaxation?

Answer 5

Higher pressure in aorta/pulmonary
artery > ventricles
Valves close
Closed ventricle
Relaxes, expands, ready to receive

Question 6

What is the end diastolic volume when mitral valve closes?

Answer 6

End diastolic volume (EDV) = 120 ml

Question 6

What is the end systole volume when aortic valve closes?

Answer 6

End systole volume
(ESV) = 40 ml

Question 7

What is the equation for ejection factor?

Answer 7

Ejection factor = SV/EDV

Question 8

What is the equation for stroke volume in relation to EDV and ESV?

Answer 8

Stroke volume = EDV-ESV

Question 9

What is the normal value for ejection fraction and what are lower values a sign of?

Answer 9

Normal value 2/3rd or more; lower values in heart failure

Question 10

What is the S1 sound and an indicator of?

Answer 10

‘lubb’
-Indicator of the closure of tricuspid/mitral values at beginning of ventricular systole

Question 11

What is the S2 sound an indicator of?

Answer 11

‘dupp’
-Indicator of the closure of aortic/pulmonary valves at beginning of ventricular diastole

Question 12

What is the S3 sound an indicator of?

Answer 12

Occasional sound
-Indicator of turbulent blood flow into ventricles, detected near end of first 1/3 diastole
-Common in young

Question 13

What is the S4 sound an indicator of?

Answer 13

Pathological in adults
-Forceful atrial contraction against a stiff ventricle
-Potentially abnormal

Question 14

What is the equation for Work (mechanical energy into increase in pressure and
movement of blood) ?

Answer 14

change in ventricle pressure x change in volume

Question 15

What does the area inside of the left ventricle pressure-volume loop represent?

Answer 15

amount of
stroke work done

Question 16

What do changes in left ventricular pressure-volume loop explain?

Answer 16

Changes in left ventricular pressure-volume loop
explain problems associated with valve disease

Question 17

What is valve stenosis?

Answer 17

narrowing of valve, doesn’t fully
open, reduces blood flow through it

Question 18

What happens in aortic stenosis and what impacts does this have on the left ventricular pressure-volume loop?

Answer 18

Aortic valve not fully open
Build up of high pressure
in left ventricle
Poor ejection
Same energy used for 50% SV

Question 19

What happens in mitral valve stenosis and what impact does this have on the left ventricular pressure-volume loop?

Answer 19

Mitral valve not fully open
Poor filling of left ventricle
Low EDV, less pressure
Reduced ejection
Poor SV

Question 20

What happens during a wave when the blood enters the heart?

Answer 20

Atrium contracting and tricuspid valve is open

Question 21

What happens in x descent when blood enters the heart?

Answer 21

Atrium relaxing then filling and tricuspid valve closed

Question 22

What happens in the V wave when blood enters the heart?

Answer 22

Atrium tense as its full.
Tricuspid valve is closed

Question 23

What happens in Y descent when blood enters the heart?

Answer 23

Atrium emptying
Tricuspid open

Question 24

What happens to pressure in neck vein during x decent and how does it look like?

Answer 24

Drop in pressure
seen as collapsing
neck vein
- looks pulsatile -

Question 25

What happens to venous pulsatile distension if pressure in right atria is raised?

Answer 25

If pressures in right atria is raised
Then height of venous pulsatile distension is increased

Question 26

What happens during right sided heart failure?

Answer 26

Poor ejection from right ventricle
More blood volume remains in right ventricle
Increased blood pressure in right ventricle,
Raised jugular venous pressure – Increased height of venous distention