Heart As A Pump/ Cardiac Cycle

Front 1

What part of a EKG precedes isovolumetric contraction?

Back 1

The QRS complex

Front 2

What signals the start of systole in a EKG?

Back 2

The R peak

Front 3

When does the mitral valve close?

Back 3

When ventricular pressure exceeds left atrial pressure

Front 4

What is the first heart sound?

Back 4

Closure of the mitral valve

Front 5

When does the aortic valve open?

Back 5

When left ventricular pressure exceeds aortic pressure

Front 6

When does the rapid ejection phase begin?

Back 6

When the aortic valve opens

Front 7

When does rapid ejection occur on a EKG?

Back 7

During the ST segment

Front 8

What is the stroke volume? How do you calculate SV?

Back 8

The volume of blood that flows into the aorta per beat

SV = EDV - ESV

Front 9

What is the ejection fraction? how do you calculate it?

Back 9

The fraction of blood ejected by the ventricle relative to its end-diastolic volume

EF = SV/EDV

Front 10

What is the cardiac output? How do you calculate it?

Back 10

The volume of blood pumped by the heart per minute

CO = SV x HR

Front 11

What wave on the EKG coincides w/ a reduction in LV contraction and pressure?

Back 11

The T wave

Front 12

Why does the aortic valve not immediately close when LV pressure drops?

Back 12

B/c of the inertia of the blood flow, which imparts considerable kinetic energy

Front 13

What propels blood into the peripheral circulatory system?

Back 13

Elastic recoil of arteries

Front 14

What is the end-systolic volume?

Back 14

The volume of blood left in the ventricle after systole

Front 15

What closes the aortic valve?

Back 15

Aortic elastic recoil causes blood to flow toward the ventricles (retrograde or negative flow) leading to aortic valve closure

Front 16

What defines the onset of diastole?

Back 16

Aortic valve closure

Front 17

What causes the S2?

Back 17

Aortic and pulmonary valve closure

Front 18

What causes the dichrotic notch in the aortic pressure waveform?

Back 18

Closure of the aortic valve which results in brief forward flow in the aorta

Front 19

When are both the mitral and aortic valves closed and no blood is entering the LV?

Back 19

Isovolumetric relaxation

Front 20

What causes pressure in the LV to drop rapidly?

Back 20

Isovolumetric relaxation occurs b/c both valves are closed and no new blood is entering the ventricle

Front 21

When does the rapid ventricular filling phase begin?

Back 21

When ventricular pressure falls below atrial pressure

Front 22

When does the mitral valve open?

Back 22

When ventricular pressure falls below atrial pressure

Front 23

When are the atrial and ventricular pressures the same?

Back 23

During rapid filling, when the aortic valve is closed but the mitral valve is open

Front 24

What drives the rise in pressure seen in the left ventricle and left atrium during reduced ventricular filling?

Back 24

Pressure in the pulmonary veins

Front 25

Where in the cardiac cycle does the P wave occur? what happens during the P-wave?

Back 25

At the end of reduced ventricular filling

Atrial contraction

Front 26

What is the end-diastolic volume?

Back 26

The left ventricular volume at the end of atrial contraction

Front 27

What is the left-ventricular end-diastolic volume?

Back 27

The pressure in the ventricle at the end of diastole

Front 28

What is a characteristic of a compliant left-ventricle?

Back 28

Pressure in the left ventricle does not increase significantly even after ventricular filling

Front 29

1. Where does the mitral valve open?
2. Where is rapid filling?
3. Where does the mitral valve close?
4. Where does ventricular filling end?
5. Where is isovolumetric contraction?
6. Where does the aortic valve open?
7. Where is rapid ejection?
8. Where is reduced ejection?
9. Where is end-systolic volume?
10. Where does the aortic valve close?
11. where is isovolumetric relaxation?
12. Where is end-diastolic volume?
13. Where is stroke volume?

Back 29

1. A
2. A-B
3. C
4. C
5. C-D
6. D
7. D-E
8. E-F
9. F
10. F
11. F-A
12. C
13. on graph

Front 30

What segment reflects a high compliance in LV?

Back 30

B-C, b/c there is only a slight increase in pressure despite a significant increase in volume

Front 31

What is the main difference b/e the left and right heart?

Back 31

The magnitude of peak systolic pressure only reaches ~24mmHg in the right heart

Front 32

1. What is the a-wave on the JVP?
2. What is the c-wave?
3. What is the v-wave?

Back 32

1. Contraction of right atrium
2. Bulging of the tricuspid valve into the right atrium as right ventricular pressure rises during systole
3. filling of the right atrium against a close tricuspid valve

Front 33

How do you calculate cardiac output using the fick equation?

Back 33

Q = VO2 / [(Ca)-(Cv)]

Front 34

How do you calculate the O2 in venous blood entering the lungs per minute?

Back 34

=QCv

Front 35

How do you calculate the O2 in arterial blood leaving the lungs per minute?

Back 35

=QCa

Front 36

How do you calculate the O2 uptake by pulmonary capillaries per minute?

Back 36

(QCa)-(QCv)

Front 37

How do you calculate VO2?

Back 37

VO2=(QCa)-(QCv)

Front 38

What is the first/last phase of diastole?

Back 38

first = isovolumetric relaxation

last = atrial systole

Front 39

What is the first/last phase of systole?

Back 39

first = isovolumetric contraction

last = reduced ejection

Front 40

What causes ventricular relaxation?

Back 40

Removal of calcium from the cytosol

Front 41

Which part of the graph reflects diastolic blood pressure? systolic?

Back 41

Front 42

If the A-B segment rises how will that affect LV volume? What would cause segment A-B to rise?

Back 42

Decrease it b/c the mitral valve will close faster

Decreased ventricular compliance

Front 43

Which point most closely depicts diastolic blood pressure?

Back 43

C

Front 44

Your blood pressure this morning is 124/76. If the denominator increased to 100 mm Hg, which phase of the cardiac cycle will be prolonged? why?

Back 44

Isovolumetric contraction; b/c the left ventricle will have to reach a higher pressure in order to overcome the pressure in the aorta and open the aortic valve

Front 45

A 54 year old woman has a resting cardiac output of 7 liters/min. Her arterial pressure is 125/85 and her body temp is normal. The diagram below is the pressure-volume curve of her left ventricle. What is her heart rate?

Back 45

Step 1: Calculate SV
EDV-ESV = 150-50 = 90mL

Step 2: Calculate EF
SV / EDV = 90/150 mL = 60%

Step 3: Calculate HR
CO = HR x SV => 7000 mL/min = HR x 90mL
=> HR = 7000/90mL = 78 bpm

Front 46

a resting human absorbs ~250 ml O2 per minute from alveolar gas (VO2). Arterial blood contains 195 ml O2 per liter and mixed venous blood contains 145 ml O2 per liter. What is Q?

Back 46

Q = 250/(195-145) = 5 L/min

Front 47

What is the pulmonary capillary wedge pressure?

Back 47

A way of measuring left atrial pressure by inserting a balloon through the RA -> RV -> PA until it reaches a smaller vessel. When the balloon is inflated the pressure on the distal side of the balloon will reach a pressure very similar to that in the right atrium