cardiac hemodynamics

What happens to atrial systole [CONTRACTION]

Occurs during ventricular diastole (RELAXATION)

What happens with atrial diastole (RELAXATION)

Occurs during ventricular systole (CONTRACTION)

What is the job of ventricles

Refill blood

In ventricular diastole where do the waves begin?

Begins at the end of T wave and ends at the onset of the QRS wave

In Bernoulli effect what does conservation of energy show?

increase in kinetic energy (velocity)

causes a decrease in pressure at the site of stenosis

Bernoulli effect describes the decrease in pressure at stenosis to what?

due to increased velocity at the site; as velocity increases, the pressure drops leading to an increased pressure gradient

Reduction in pressure in Bernoulli effect is seen in?

with an increased blood velocity; decreased pressure = increased flow

Reynolds's # above 2,000 shows what?

Turbulence

Why is color Doppler helpful t0 evaluate turbulence flow?

Shows regurgitation

• Proximal Isovelocity Surface Area (PISA) area of narrowed opening blood flow squeezes together enter stenotic area

If an area of uniform flow moves through an narrow opening?

Vena contracta

Frank - Starling Law is ?

Relationship B/t venous return & stroke volume

In frank starling law ; what will cause increased stroke volume?

Increased Venous return (preload)

With franklin starling law what improves cardiac performance?

increase in preload will lead to improved cardiac performance with

increased stroke volume and cardiac output

What is left ventricle preload?

pulmonary wedge pressure = left atrial pressure or

end diastolic left ventricular pressure

What is right ventricular preload?

central venous pressure = right atrial pressure

Can preload increase?

yes ; due to valvular regurgitation and flow shunting with

septal defects

Increased preload causes?

increased contractility of the ventricle

Increased afterload is associated with?

valvular stenosis, systemic and pulmonary HTN and aortic coarctation

What does increased afterload cause?

decrease in cardiac performance and increase in

ventricular wall thickness

Afterload is what?

resistance the left ventricular contraction must overcome for flow

ejection

What is the average CC in stroke volume?

70- 100

How is stroke volume measured?

Amount of blood pumped out of the heart with each beat

What is the stroke volume Doppler method?

Area x VTI

2D: EDV- ESV

Where do you measure stroke volume ?

LVOT; level aortic annulus , proximal valve leaflets

Where is LVOT diameter measured?

parasternal long-axis view at mid systole

What is cardiac output?

Amount of blood pumped out of the heart each minute

● SV x HR

Where is cardiac output LVOT diameter measured?

PLAX view and trace LVOT velocity in apical 5

chamber view

Explain ejection fraction ?

Measure the end diastolic and end systolic volumes

% of blood ejected during each contraction

Ejection fraction End Systole & End Diastole do what?

End Systole - frame just before the mitral valve opens

End Diastole - first frame after the mitral valve closes or peak of the R wave

EDV - ESV / EDV = EF%

What changes to circulation happen while a patient is breathing?

Inspiration = increases venous return & stroke volume

= increase right heart murmurs

Expiration = decreases venous return

= increased left heart murmurs

During standing what circulations changes are seen?

Decreased venous return & stroke volume

Valsalva changes to circulation are?

Strain = decreases venous return, stroke volume, cardiac output

= increased murmurs associated w/ subaortic stenosis

Release = increases venous return, stroke volume & cardiac output

Handgrip increases BP, CO, and total peripheral resistance ; what else can this increase ?

Murmurs associated w / AS, PS, MR, AR ,VSD

What is the normal valve open pressure?

4mmHg pressure gradient present

(1 m/s aortic velocity = 4mmHg pressure gradient between LV and Aorta)

What happens when a valve becomes stenotic?

blood flow velocity across the valve increases

and the pressure gradient between chambers increases