08 Cardiovascular System Baru

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Cardiovascular SystemCardiovascular System

Overview of Anatomy & PhysiologyOverview of Anatomy & Physiology

Assessment of CV FunctionAssessment of CV Function

Ezra OktaliansyahEzra Oktaliansyah

e!artment of Anesthesiology & "eanimation #edical Faculty

Pad$ad$aran %niversity dr' (asan Sadikin )eneral (os!ital

*andung



Function of the heart:

pump oxygenated (saturated) blood into the

arterial system, which carries it to the cells

pump deoxygenated (desaturated) blood

back to the lungs via the veins for

reoxygenation



heart size depends on the size of the person

approximately the size of the fist

encased in a thin, fibrous sac called the

pericardial sac or pericardium (2 layers)

composed of three layers: inner layer endocardium middle layer myocardium

outer layer e!icardium



!ardiac chambers:

"ight atrium receives deoxygenated blood

from the superior and inferior vena cava

(venous return)

"ight ventricle pumps blood against a low

resistance in the pulmonary artery (#$") on

the way to the lungs where oxygenationtakes place



%eft atrium receives oxygenated blood

from the lungs via & pulmonary veins

%eft ventricle pumps blood to the systemic

circulation via the aorta against a high

resistance ('$")



!ardiac valves:

ensure one way flow of blood

two types:

atriovenricular valves mitral (btw % * %$)

tricuspid (btw " * "$)

closed during $+ systole and therefore prevent

backflow of blood to the atria during ventricularcontraction (systole)

open during ventricular relaxation (diastole)

allowing for filling of the ventricles



semilunar valves

pulmonic valve (btw "$ * pul+ artery)

aortic valve (btw %$ * aorta) closed during v+ diastole and prevent backflow

into the ventricles during relaxation (ventricular

diastole)

unlike the $ valves, they are open during

contraction of the ventricles (ventricular

systole) allowing for emptying of the ventricles



!ardiac cycle

eart muscle contracts * relaxes

rhythmically to assure proper circulation

one cardiac cycle-. heart beat

two phases to the cardiac cycle: systole

diastole



'ystole

ventricles contract

blood e/ected from the %$→aorta and from

the "$→ pulmonary artery



0iastole

ventricles relax

pressure in the ventricle falls below that of

the atria

the $ valves open

blood which has been pooling in the atria

begins to flow into the ventricles



as systole begins the $ valves (mitral *

tricuspid) close, '. (1lubb) produced

semilunar valves forced open, a silent event



3hen ventricles are almost empty, pressure in

the ventricles drops, allowing the semilunar

valves (pulmonic and aortic) to close, '2(1dubb) produced

at this time atrial pressure higher, mitral *

tricuspid valves forced open, passively fillingthe ventricles up to a certain point (if rapid

filling of dilated ventricle, '4 possible)



to ensure that the blood remaining in the

atria is e/ected, the atria contract (atrial

kick)

if there is any resistance to filling by the

ventricle, '& possible



5lectrical activity

n electrical conduction system is

responsible for the se6uence of muscle

contractions that take place during thecardiac cycle

in essence an electrical current stimulates

each contraction under normal circumstances, this electrical

impulse originates in the ' node



this property of the ' node to initiate an

impulse is known as +automaticity,

automaticity can be disturbed in 78 (d9thypoxia), electrolyte imbalance, acidbase

imbalance, drugs, etc+

onautomatic cell may become automaticand subse6uently cause dysrhythmias, (e+g+,

#!s, #;!s, #$!s, escape rhythms, etc+)



ormal conduction pathway

SA node via internodal tracts to AV node to the

*undle of (is

the <undle of is then divides into the "ight*undle *ranch * the -eft *undle *ranch

each branch terminates to form the Purkinge

fi.ers located in the ventricular myocardium,where the ventricles, when stimulated, contract



=wo electrical events

(recorded as waves on 5>?): de!olarization the spread of an electrical

impulse through the heart muscle

re!olarization the return of the heart muscleto a resting state

the corresponding mechanical events are

contraction and rela/ation, respectively =he ability of cardiac cells to respond to an

electrical impulse is called +e/cita.ility,



=he se6uence of depolarization and

repolarization is called the cardiac action

!otential+ 8t results when ions (charged particles such

as a, >, * !a) shift across the cell

membrane+



!onductivity

"efers to the ability of the heart muscle

fibers to transmit electrical impulses along

and across cell membranes can be enhanced or depressed by drugs,

ischemia, trauma



!ontractility

"efers to the heart muscle fibers ability to

contract, or shorten, in response to an

electrical impulse (irrespective of volume) can be impaired in 78, electrolye

disturbances, drugs, hypoxemia

decreased contractility results in a drop in thestroke volume and ultimately leads to a drop

in cardiac output



"efractoriness

"efers to the heart@s inability to respond to a

new stimulus while still in a state

depolarization from an earlier stimulus this prevents the possibility of tetanic

contractions that would be fatal



5lectrical activity *

corresponding waves on 5>? # wave corresponds to the spread of the

impulse through the atria atrial

de!olarization #" interval conduction time through the

atria (+.2+2A sec+)

B"' complex corresponds to spread of theimpulse through the ventricles ventricular

de!olarization



B"' interval conduction time through the

ventricles (+A&+.2sec+)

'= segment * = wave return of stimulated

ventricular muscle to a resting state

ventricular re!olarizationCC

B= interval time it takes for the ventriclesto depolarize * repolarize



!oronary circulation

eart muscle itself re6uires a supply of

oxygenated blood to meet its own metabolic needs

supplied through the coronary arteries which branch off from the aorta /ust above the aortic

valve, encircle the heart, and penetrate the

myocardium

returned to right side of the heart via the coronary

veins



"ight !oronary rtery ("!)

%eft 7ain !oronary rtery (%!): %eft anterior descending (%0)

!ircumflex artery



!ollateral !irculation

=he presence of more than one artery

supplying a muscle (a capacity present at

birth but not functional) develops when the blood flow through an

artery progressively decreases and causes

ischemia to the muscle extra blood vessels develop to meet

metabolic needs of the muscle



!ardiac Dutput

$olume of blood e/ected by the heart9min+

(E &%)

'troke volume G heart rate

cardiac index a calculation that helps to

determine if !D is ade6uate in relation to

body size !8-!D9<' (0ubois scale) in %9min9m2



'troke volume

0etermined by: preload

afterload contractile state of the myocardium



#reload

7yocardial fiber length of the ventricle at end

diastole

also known as amount of stretch 'tarling@s law (↑ stretch →↑ force of

contraction) C

stretch determined by volume of blood inventricle

#reload - $enous "eturn



fterload

=he resistance against which the ventricle must

e/ect its volume

amount of pressure re6uired by the %$ to openthe aortic valve during systole and to e/ect

blood into the systemic circulation ('$")

afterload for right side of the heart (#$")

inversely related to stroke volume

related to <# ( systemic9pulmonary)



!ontractile (inotropic) state

"efers to the vigor of contraction generated

by the myocardium regardless of its blood

volume (preload) increased by '' stimulation (epinephrine

endogenously or exogenously)

decreased by hypoxemia9acidosis



"egulation of !$ system

involuntarily controlled by the '

the ' plays a role in regulating

heart rate (chronotropic effect) myocardial contractility (inotropic effect)

conduction velocity at the $ node

peripheral (systemic) vascular resistance

arteriole constriction and dilation

venous return

venule and vein constriction and dilation



=he two subdivisions of the '

(sympathetic * parasympathetic) generally

exert opposing influences and balance theiractivities to promote cardiovascular

adaptation to internal and external demands



#arasympathetic nervous system

7ediated via the vagus nerve

when stimulated, parasympathetic nerve

endings release the neurotransmitteracetylcholine, which produces inhibitory

effects

decreases the rate of ' node firing, thuslowering "

lessens atrial conductivity



'ympathetic nervous system

7ediated by <eta receptors

when stimulated, the nerve endings release the

neurotransmitter norepinephrine and producethe following effects: increase in heart rate

increase in conduction speed through the $ node increased atrial and ventricular contractility

peripheral vasoconstriction (H result)



ormonal * other influences on

!D 0

reninangiotensinaldosterone mechanism

exercise, anger, fear, pain, anxiety, excitementcan augment the '' effects

drugs

I2 adrenergic agonists stimulate '' (↑") I blockers <lock '' (↓")

cardioselective I blockers (block only I. receptors)



<lood pressure

5xpressed as systolic blood pressure9diastolic

blood pressure

'<#peak pressure exerted against arterieswhen heart contracts (measure of contractile

function)

0<#residual pressure during relaxation ofthe heart (↑er in atherosclerosis)

<#-!Dx'$"



8mportant receptors

!hanges in sympathetic and

parasympathetic activity occur in response

to messages sent from sensory receptors invarious parts of the body

for cardiovascular function, the important

receptors are: arterial baroreceptors, stretchsensitive cardiopulmonary receptors of the

atria and veins, and chemoreceptors



<aroreceptors

'tretch sensitive nerve endings affected by changes

in art+ <#

located in the walls of the aortic arch and carotidsinuses

stimulated by an ↑in art+ <#, a vagal response

results in ↓in heart rate and art+ <#

with ↓ <#, less stretch, fewer impulses, see

sympathetic mediated ↑ in " and vasoconstriction



!ardiopulmonary stretch

receptors located in vena cava * atria

respond to length changes, reflective of circulatory

volume status with ↓ in <# in vena cava and " due to

hypovolemia, stretch receptors send fewer impulses

than usual to the !'

result is a sympathetic response to kidney to

enhance a and water retention * release of 0

(hypervolemia produces the opposite)



!hemoreceptors

Found in the aortic arch and carotid bodies

sensitive to ↑ !D2 and ↓arterial p

(acidemia) and secondarily sensitive tohypoxemia

when such changes occur, they send

impulses to the !' to increase "



'ome factors affecting <#

cardiac output9blood volume

systemic vascular resistance

elasticity of blood vessels blood viscosity

age

weight

emotion

exercise



ssessment of !$ function

istory

#hysical 5xamination inspection

palpation

percussion

auscultation

%ab * 0iagnostic =ests



#resent istory

!hief complaint * symptom analysis

(#B"'=)

chest pain dyspnea (0D5, othopnea, #0)

cough (hemoptysis)

palpitations skipped beats

dizziness, fainting, syncope



fatigue9weakness

weight gain

peripheral skin changes (e+g+, edema, #$0) leg pain



#ast istory

ypertension

0iabetes

"heumatic fever9"heumatic heart disease

5levated homocysteine levels (homocysteine,

an amino acid produced in the body, is

considered to be a contributing risk factor andis associated with <.2, folic acid, and <J

deficiencies)



%ifestyle

7ay constitute modifiable risk factors for

heart disease

smoking elevated cholesterol levels9high fat diet (esp+

saturated fats)

sedentary activity9physical inactivity obesity

stress



#hysical 5xamination

8nspection color

presence of clubbing capillary refill

edema

vital signs peripheral pulses

level of consciousness (%D!)



8nspection cont@d ;$#

urine output #78

xanthelasma

arcus senilus ear lobe creases



#ercussion

#alpation thrill

heave9lift

abdomen

liver (including the hepato/ugular reflex)



uscultation normal heart sounds ('., '2)

abnormal heart sounds ?allops ('4, '&)

pericardial friction rub

murmurs

bruit

lung sounds



%ab * 0iagnostic =ests

!hest xray

5>? * cardiac monitoring

'tress test (5==)

5lectrophysiological studies

!ardiac catheterization

ngiography



5chocardiogram

8ntraarterial pressure monitoring

emodynamic monitoring (!$#, # )



!<! (gb, ct, 3<!, #latelets)

'erum lipids

!ardiac enzymes

<lood coagulation

'erum electrolytes

<K * !r

0rug levels

08 Cardiovascular System Baru

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