The Heart as a Pump

Question 1

Isovolumic contraction

Answer 1

• Onset occurs with R wave
• 1st heart sound here due to closing of AV valves
• rise in LV pressure from 10->80mmHg

Question 2

Ejection

Answer 2

RAPID: semilunar valves open; rapid increase in aortic flow; rapid decrease in ventricular volume; sharp inc in aortic and vent p to 120mmHg; c wave

REDUCED: flow from aorta to periphery exceeds that of LV output so pressure drops; aortic flow drops; atrial pressure rises due to filling from veins

Question 3

Isovolumic Relaxation

Answer 3

• Aortic valve closes due to aortic pressure > LV pressure
• this causes the second heart sound and the notch (incisura)
• ALL valves closed
• rapid fall in LV Pressure
• aortic pressure remains high
• v wave

Question 4

Rapid filling phase

Answer 4

• AV valves open due to LV pressure dropping below that of LA pressure
• rapid increase of LV volume

Question 5

Slow filling

Answer 5

• Diastasis

- a gradual rise in atrial, ventricular and venous volume

Question 6

Atrial systole

Answer 6

• soon after P wave
• a wave
• not essential but needed in exercise

Question 7

What are the venous pulse waves? (typically look at RA)

Answer 7

a wave- retrograde pressure pulse in jugular when atria contract
c wave- early systole
v wave- gradual increase in pressure during reduced ejection and IVR