Pressure/Volume Relationships

Question 1

How does ventricular Hypertrophy affect the functional relationship of ventricular volume(x) to pressure (y)?

Answer 1

HYPERTROPHY = increased wall thickness; P & thickness are directly proportional to one another; So increased wall thickness will increase the ventricular pressure leading to an increased filling curve and an increased stroke volume

Question 1

Define ESPVR & EDPVR

Answer 1

ESPVR is a measure of the heart’s ability to contract (inotropic response associated w/ slope); EDPVR is a measure of ventricular compliance; in other words how easily can the heart expand (reciprocal of slope)

Question 2

How will ventricular hypertrophy affect ESPVR & EDPVR?

Answer 2

Increased ESPVR (increased ESPVR slope) & decreased compliance (increased EDPVR slope)

Question 3

How will dilated cardiomyopathy affect the relationship b/t ventricular volume & pressure?

Answer 3

decrease in wall thickness will decrease pressure & therefore decrease filling curve and SV

Question 4

How will dilated cardiomyopathy affect ESPVR & EDPVR?

Answer 4

decreased ESPVR slope; increased compliance (reduced ESPVR slope)

Question 5

An increase in HR will reduce SV (less time is being spent in diastole) and maintain a constant CO up until a point; b/t what range of HR will the CO be increased & decreased?

Answer 5

180-200 bpm: CO increases; beyond 200 bpm: CO & SV decrease

Question 6

what is the relationship b/t preload & ventricular contraction/SV?

Answer 6

An increase in preload will increase SV & force of ventricular contraction

Question 7

During exercise is the preload increased or decreased?

Answer 7

decreased

Question 8

what is the relationship b/t SV & afterload?

Answer 8

Inverse proportion

Question 9

Is blood volume going to be increased or decreased if afterload is increased?

Answer 9

a greater afterload means more blood is being kept in the heart chambers

Question 10

What effect does HTN have on afterload & SV?

Answer 10

decreases afterload which will increase SV

Question 11

How does norepinephrine affect SV?

Answer 11

it increases it

Question 12

How does calcium affect isovolumetric relaxation?

Answer 12

isovolumetric contraction will be increased if the rate of Ca uptake into the ER is increased

Question 13

How does calcium affect force of contraction?

Answer 13

force of contraction will be increased if rate out Ca efflux relative to intracellular concentrations is decreased (higher Ca intracellular concentration)

Question 14

What is the equation for Ejection Fraction?

Answer 14

SV*100/EDV

Question 15

what are the qualitative and quantitative definitions of fractional shortening?

Answer 15

fractional shortening is a measure of how well the left ventricle contracts; it is the same equation as EF

Question 16

How will vasodilation affect preload & afterload?

Answer 16

it will decrease both

Question 17

Myocardial O2 demand is directly proportional to what 4 factors?

Answer 17

contractility; afterload; HR; wall tension

Question 18

Would you expect EF to be increased or decreased in CHF?

Answer 18

decreased