Determinants of Cardiac Performance

Question 1

what is happening in diastole?

Answer 1

mitral valve is open
blood flows from left atrium to left ventricle
aortic valve is closed

Question 2

what is happening in systole?

Answer 2

mitral valve closes
aortic valve opens
blood leaves the left ventricle and goes into aorta

Question 3

what is a pressure volume loop?

Answer 3

real time change of volume and pressure

Question 4

when does ventricular filling begin?

Answer 4

mitral valve opening

Question 5

what happens with pressure and volume during ventricular filling?

Answer 5

volume in the left ventricle increases
pressure increases slightly

Question 6

when does ventricular filling end?

Answer 6

ventricular contraction after end of diastole

Question 7

when does isovolumetric contraction begin?

Answer 7

onset of systole

Question 8

what valve is closed at the beginning of isovolumetric contraction?

Answer 8

mitral valve

Question 9

when does ejection begin?

Answer 9

when aortic valve opens

Question 10

what is the pressure volume loop strictly bounded by?

Answer 10

end diastolic pressure volume relationship
end systolic pressure volume relationship

Question 11

what is compliance inversely related to?

Answer 11

stiffness

Question 12

what is preload?

Answer 12

the force which fills the heart
the extent of filling of the heart before contraction
wall stress at diastole

Question 13

when does end systolic pressure volume relationship occur?

Answer 13

maximal contraction

Question 14

what does the laplace relationship tell us?

Answer 14

force experienced or exerted by each sarcomere

Question 15

is contractility independent of afterload and preload?

Answer 15

yes

Question 16

what is contractility determined by?

Answer 16

conditions within the myocyte

Question 17

what does increased preload lead to?

Answer 17

increased stroke volume

Question 18

what are the two components of synergy of contraction?

Answer 18

atrioventricular synchrony
inter-ventricular synergy

Question 19

what does inter-ventricular synergy require?

Answer 19

functional bundle branches (purkinje fibers)

Question 20

what does an increase in heart rate do to stroke volume?

Answer 20

decreases it

Question 21

what are the methods to increase cardiac output?

Answer 21

increase heart rate
increase stroke volume

Question 22

how can you increase stroke volume?

Answer 22

increase preload
decrease afterload
increase contractility

Question 23

what happens if afterload increases (and no other determinants)?

Answer 23

end systolic volume increases
stroke volume decreases

Question 24

what is the common theme in compensation?

Answer 24

increase preload

Question 25

what happens to pressure and volume as blood is ejected from the left ventricle?

Answer 25

volume decreases and pressure continues to increase

Question 26

what does the pressure volume loop tell us?

Answer 26

how good of a pump a particular heart is: how much blood per contraction, does it contract well, does it relax well

Question 27

where is afterload on the pressure volume loop?

Answer 27

point where contraction stops

Question 28

where is preload on the pressure volume loop?

Answer 28

point when contraction begins

Question 29

what is contractility on the pressure volume loop?

Answer 29

slope of upper boundary

Question 30

what is compliance and distensibility on the pressure volume loop?

Answer 30

slope of lower boundary

Question 31

what is contractility determined by?

Answer 31

conditions within myocyte
not afterload and preload

Question 32

does an increase in preload or afterload lead to an increase in stroke volume?

Answer 32

preload

Question 33

what is needed for atrioventricular synchrony?

Answer 33

functional AV node and his-purkinje

Question 34

what does inter-ventricular synergy require?

Answer 34

functional bundle branches (purkinje fibers)

Question 35

what does increasing heart rate increase?

Answer 35

cardiac output up to certain point
force of contraction slightly

Question 36

how can you increase stroke volume?

Answer 36

increase preload
decrease afterload
increase contractility

Question 37

the normal heart is said to be ____________ dependent and ____________ independent

Answer 37

preload
afterload

Question 38

what is the common theme in compensation?

Answer 38

increase preload