Physio - Curve Shifting

Question 1

PV Loop Changes due to increased preload

Answer 1

high preload = increased stretch = increased EDV = increased SV

Question 2

PV Loop Changes due to increased afterload

Answer 2

high afterload = more force opposing contraction = increased ESV = decreased SV

Question 3

PV Loop Changes due to increased contractility

Answer 3

high contractility = more intrinsic ability to squeeze = steeper slope (upshift) of ESPVR (same pressures squeeze out more volume) = Decrease ESV = increase SV

Question 4

PV Loop Changes due to decreased compliance

Answer 4

decreased compliance = stiffer ventricle = less volume change per pressure change = increase in slope (upshift) of EDPVR (after filling, less volume obtained at same pressure) = decreased EDV = decreased SV

Question 5

Frank Starling Relationship

What happens with increased contractility or HF?

Answer 5

FSR: more stretch = more force generated
Increased LV EDV = Increased SV

Increased Contractility: upshift of curve
HF: downshift of curve (but can still move along it)

Question 6

Vascular Function Curve: which line is which?

Answer 6

RA Pressure (x-axis) vs. CO (y-axis)
Upper Left to Lower Right: Vascular Function (As CO increases, blood forced into arteries, less blood in venous system - drop in RA Pressure)

Lower Left to Upper Right: Cardiac Function (As RAP increases = more stretch = more force of contraction = more SV = more CO)

Question 7

Vascular Function Curve: Increase Contractility

Answer 7

Increased contractility = shift cardiac function curve up/left = increase in operating point CO

Question 8

Vascular Function Curve: Increase Plasma Volume

Answer 8

VASCULAR CURVE UP/RIGHT SHIFT
(increase CO)
More volume = increase in MAP = increase in Venous Return at all cardiac outputs
when cardiac output is zero, veins more distended - shift zero point rightward as well

Question 9

Vascular Function Curve: Increase Venous Tone

Answer 9

VASCULAR CURVE UP/RIGHT SHIFT (increase CO)

More venous tone = veins distend with less volume = similar shift to increased blood volume

Question 10

Vascular Function Curve: Increase in SVR

Answer 10

CARDIAC + VASCULAR CURVES DOWNSHIFT
(decrease CO)

more SVR = more afterload = less CO (cardiac curve)

more SVR = less venous return (more blood in arterial system) [vascular curve]
*note vascular curve zero point does not change due to no change to distended volume