Session_1.ppt

7/29/2019 Session_1.ppt

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CARDIOVASCULAR

PHYSIOLOGYHow the Circulation Works

Burt Hamrell, M.D., Ph.D.


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, ,

What is heart failure?

Heart Failure/Heart Disease (CVD) is the #1 cause of

death in the US. (~25% of deaths/year)

The etiology (cause) of Heart Disease can be due tovarious abnormalities that result in a dysfunctional

heart.

MOST COMMON CAUSE OF HEART DISEASE IS

ISCHEMIA (IHD)primarily due to reduced blood

supply from the major coronary arteries (LAD, LCX,

RCA/PDA)


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PRESSURE


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Total Pressure Kinetic Gravitational

Energy = Potential + Energy + Potential

Energy Energy

W = P + rv2 +

2

gh

Pressure Potential Energy is the primary determinant for blood flow:

Generated by massive pressure (force) from LV contraction that creates

a large pressure in the aorta (Paorta).

Reason why blood continues to flow: DIFFERENCE between

Paorta and Pra (right atrium) is considered an energy difference

(pressure difference):

Paorta = ~130mmhg vs. Pra = ~5mmhg

Hydrostatic

Pressure


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Fluids flow because of pressure differences between

ENTRY (aorta) and EXIT (right atrium) points

DOES NOT DEPEND ON THE PATH OF TRAVEL!

Alsoin this example, there is no pump (heart), so

ONLY HYDROSTATIC PRESSURE (see previous

slide) creates a pressure difference.height of water pressure difference flow


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StreamlineSilent flow (laminar)Flow

TurbulentNoisy flow (murmurs/bruits)


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LVToBody

Aortavelocity at center vs. velocity at periphery (due to internal viscosity sticky)


8/67From LVTo Body


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(A): height of fluid P flow (velocity) laminar flow

UNTIL:

(B): Once the internal viscosity of the fluid (stickiness) gets disrupted

due to large velocity (flow) becomes turbulent flow!

(C): ALSOstenosis (constriction/narrowing) causes larger velocity

in order to maintain constant flow downstream turbulence!

V = Q/A


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e

v D

R

Mean

Velocity

DiameterDensity

Viscosity

**Increase enough in

Reynoldss Number can

result in turbulence.**

KNOW THIS!


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PATIENT75 years old

Murmur for several years

Symptoms last six months

Enlarged heart & murmur

Lung fluid


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Aortic Valvular

Stenosis

Narrow aortic

valve orifice


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A rr D

2

2

3

2

Q(cm / sec)v(cm / sec)

A(cm )

QvA


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A r

r D

2

2

Qv=

A

e

v D R =

D V Re

murmurs! (in order to

maintain same flowQ)


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Narrowed aortic valve (stenosis) D V

turbulent flow DOWNSTREAM (murmur heard in

aorta) MSM (mid-systolic murmur) occurs

AFTER S1 and ends BEFORE S2 (will hear both heart

sounds normally, with murmur occurring in between)


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e

v DR =

Q


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Clinical Examples

2. QPregnancy

3. viscosity

Anemia

ev DR

Qv

A

1. D vAorticStenosis

ALL 3 EXAMPLES WILL

CAUSE Re which will

result in murmurs/bruits

KNOW THESE!

(will hear bruits

throughout the body)


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Velocity of

Flow in the

Circulation

Qv A

Area velocity(must know at least 2 variables to draw

conclusions about the 3rd)

With constant flow of 5L/min


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2. The velocity of blood flow:

A. in each capillary is high because the cross-sectional area of

each capillary is very small.

B. in the veins is less than in the venules.

C. is greater at the root of the aorta than in the arterioles.

D. is greater towards the periphery than towards the center of

the aortic stream.

E. must be increased through a narrowed pulmonary valve.


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2. The velocity of blood flow:

A. in each capillary is high because the cross-sectional area of

each capillary is very small.

B. in the veins is less than in the venules.

C. is greater at the root of the aorta than in the arterioles.

D. is greater towards the periphery than towards the center of

the aortic stream.

E. must be increased through a narrowed pulmonary valve.

The reason why I included this question is to emphasize the

point to READ EVERY ANSWER CHOICE THOROUGHLY,

and to select the answer that is ALWAYS CORRECT!


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CARDIAC CYCLE

Burt B. Hamrell, M.D., Ph.D.

Room 236; [email protected]


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Dr. Hamrell does a wonderful job explaining the

events of the cardiac cycle.

Instead of retyping his notes, I am going to encourage

you all to read his notes on pages 1215which is

specific for the cardiac cycle. I will discuss the events

in detail during our tutoring session.

HIS NOTES ARE VERY, VERY WELL WRITTEN,

AND I HOPE YOU ALL READ THEM,UNDERSTAND THEM, LOVE THEMif not

contact me so I can resolve your areas of confusion.


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S3S4

34

bl f


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www.blaufuss.org


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S1 mainlyvalve closure


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PHYSIOLOGICAL SPLITTING OF S2:

Inspiration: diaphragm moves down, ribs move up andoutvolume in chest cavitypressureexansion of

pulmonary vessels (thin walls)compliance (larger

storage of blood) allows more blood to flow from RV

pulmonary artery delays pulmonary valve closure (P2)

ALSO: more blood stored in pulmonary veinLA

fillingLV ejection aortic valve closes sooner (A2)

Expiration: diaphragm moves up into thoracic cavity, ribs

depress back downthoracic volumepressure

causes A2 to close nearly at the same time as P2.


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CRBBB:

Delayed RV

depolarization -

causes WIDER

splitting betweenA2 and P2

during both

inspiration and

expiration!

CLBBB


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Paradoxical Splitting of S2(also seen insevere aortic stenosisbecause LV must develop a

lot of pressure to eject bloodtakes longer, and results in

prolonged A2 as shown above)

Insp

CLBBB:

Delayed LV

depolarization

Inspiration:

A2 P2

Expiration:

P2 A2


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Normal: pregnancy, young adults/teens

Pathological: ventricular hypertrophy/dilatation (RV or LV)

Occurs duringRAPID VENTRICULAR FILLING (diastole) because

either an abnormal volume of ventricular filling or due to thickened

ventricular wallcauses blood to vibrate/bounce = S3


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ALWAYS PATHOLOGICAL!

Occurs duringATRIAL KICK (diasole) that causes blood tovibrate off ventricular chamberusually due to HYPERTROPHY,

but can also be due to dilatation!

*Note: Hypertrophy = muscle mass vs. Dilatation = blood within chamber

M


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MurmursSTENOSIS: abnormal opening Narrowed valve

murmur heard downstreamex) - aortic stenosis heard in aorta (during systole)

- mitral stenosis heard in LV (during diastole)

REGURGITATION/INSUFFICIENCY: abnormal closing leaky/loose valve murmur heard upstream

ex)aortic regurgitation heard in LV (diastole)

- mitral regurgitation heard in LA (systole)

*Note: insufficiencies usually cause murmurs to appear throughout the cardiaccyclehowever the PRIMARY murmurs are indicated above. In the case of aortic

insufficiency, a larger volume will flow back into the LV, which will cause another

murmur to be heard during systole (known as To-and -Fro). Same rationale

applies for mitral insufficiency (known as pansystolic/holosystolic)or can result in

an S3.


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Reynolds Number, Re

ev DR

Turbulenceand NoiseMean

VelocityDiameter Density

Viscosity

HERE IT ISAGAIN!

KNOW THIS!


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Clinical Physiological

Systole S1 to S2 AV valve closing

to openingDiastole S2 to S1 AV valve opening

to closing

For information only

This is what is used clinically


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SYSTOLE DIASTOLE

CLINICAL

KNOW THIS DEFINITION!


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First, what structural abnormalitywhat valve defect.

Second, when during the cardiac cycle should valve be

completely closed or fully open.

Conclude,if the valve orifice is narrow, then the murmur

will occur when the valve is supposed to be fully open with

blood flowing through it. If valve is leaking the murmur willoccur when it is supposed to be closed and no blood flow is

supposed to occur.

Murmur: Where in the Cardiac Cycle?


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Aortic Stenosis

Ejection Sound (ES):

mobile Ao valve leaflets

bicuspid ASeasily confused with S1

Ejection Murmur:

begins with ES, not S1

ends before S2

MOST COMMON CAUSE ISDUE TO CALCIFICATIONOCCURS DUE TO AGING!

(USUALLY >75yrs of age)

Notice how large LV Pressure


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Notice how large LV Pressure

is! (shown below) vs.

Should be same as aortic

(shown to the right)


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See video, AS Angio, in video folder on Angel

Narrowed aortic valve (stenosis) D V

turbulent flow DOWNSTREAM (murmur heard inaorta) MSM (mid-systolic murmur) occurs

AFTER S1 and ends BEFORE S2 (will hear both heart

sounds normally, with murmur occurring in between)

Aortic Valve Regurgitation or Incompetence


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Aortic Valve Regurgitation or Incompetence

3rd l ft I t t l (3LICS)


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TO-FRO Murmur: In this case, S2 is NOT clearly heard, and themurmur obscures P2 the Early Diastolic Murmur (EDM) is due to

backflow of blood from the aortato the LV this increases LV

volume which causes a larger volume to be ejected from the LV on

the subsequent contraction giving rise to Systolic murmur (SM)

3rdleft Intercostal space (3LICS)

Aortic Regurgitation


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Inspection:

bounding (Corrigans) pulse

head bobbing (Mussets sign)compare with normal carotid

Auscultation:

To-fro murmur

Midsystolic murmur Early diastolic murmur


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WHAT IS THE DIAGNOSIS (DX)?


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THIS IS MITRAL STENOSIS!easy DX!

Notice a similarity betweenaortic stenosis? YES!LA Pressure is much higher than LV pressure during

diastole, when these pressures should be the same (this is

similar between the LV pressure and Aortic pressure seen in

aortic stenosis!)

THE FOLLOWING SLIDES ARE


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THE FOLLOWING SLIDES ARE

CASE STUDIES THAT DR.

HAMRELL PRESENTED DURINGLECTURE.

EXPLANATORY NOTES ARE

LOCATED BENEATH EACH

SLIDE, OR CAN BE VIEWED BY

CLICKING NOTES PAGE

UNDER VIEW

A 78 Y/O t li


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A.78 Y/O man; systolic murmur

Location of Turbulence?

Aorta.

Cause of Turbulence/Murmur?

High velocity across aortic valveduring ejection.

S2 affected?A2 delayed.

Additional Information?Location during systole.

AORTIC

STENOSIS!

Aortic Stenosis


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Ejection Sound (ES):

mobile Ao valve leaflets

Aortic Stenosis

e

v D

R =Q

v

A

Midsystolic Murmur:

begins with ES, not S1ends before S2


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A2 P2

Normal

A2P2

Severe AorticValvular Stenosis

ParadoxicalSplitting of S2

Exp Insp

B. 55 Y/O man; exertional SOB; BP 178/40


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mm Hg; has murmurs

Additional Information?

Location in cardiac cycle.

Cause of Turbulence/Murmur?High velocity from aorta to LV in diastole,but also from LV to aorta during ejection.

Location of Turbulence?Diastolic murmur LV; systolic murmur ejection into aorta

BP?High pulse pressure.

AORTICREGURG!



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Auscultation:

To-fro murmur

Midsystolic murmur Early diastolic murmur

ort c egurg tat on

178

40

P

ressure

mm

Hg


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LV LVAorta


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Still Frame

LV

Aorta


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C. 37 Y/O Haitian woman; murmur,


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; ,easy fatigue. LA dilatation on Xrayand echocardiogram

LA Enlargement?Increased volume in LA

(Etiology?)

Rheumatic carditis.

Location of Turbulence?Left atrium.

Additional Information?Location of murmur in cardiac cycle.

Cause of Turbulence/Murmur?High velocity of regurgitant blood flow.

MITRAL

REGURG!

Chronic MR


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Chronic MR

Inspection:

apex beat displaced leftward

outward excursion ofstethoscope head duringsystole (heave)

Auscultation:

murmur is holo- orpansystolic heard best overLV

S3

Aorta


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LA

D. 28 Y/O Grenadian woman; severe


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SOB late in pregnancy; fluid in lungs;murmur; ECG: left atrial hypertrophy

Location of Turbulence?LV

Cause of Turbulence/Murmur?

High flow velocity through narrow mitralvalve.

LAH?Increased LA pressure load.

Additional Information?Location of murmur in the cardiac cycle.

SOB?Will be discussed in future

lectures. (Etiology?)

MITRAL

STENOSIS!

Mitral Stenosis


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Loud S1:elevated LA pressure and

stiff leaflets

Opening Snap:mitral valve opens earlierthan normal ( LA pressure)fused leaflets abruptly halt

mitral valve opening, causingOS


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LA

AortaLVLA

LA

Aorta

Aorta

LV

LV

E 50 Y/O man; has a history of


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E. 50 Y/O man; has a history ofischemic heart disease (coronary

artery narrowing with damage to heartmuscle); no symptoms; ECG:

What auscultatory findings do you expectin this patient?

CLBBB! (w/paradoxical

splitting S2)


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A2 P2

Normal

A2P2

CLBBBParadoxicalSplitting of S2

Exp Insp


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F. 40 Y/O woman; systolic murmur; bilateralcarotid bruits and bruits over femoral

arteries, brachial arteries, etc.

Likely Valve Problem?

Turbulence?Cardiology Consult?

e v D R =

SEVEREANEMIA!

Increased in anemia


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e v D R =

Decreased in anemia

Qv = A

Increased in anemia

OVERALL:

RESULTS

IN Re(Turbulent flow

throughout body)

Session_1.ppt

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