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8/8/2019 Medsurg Cardio Ana&Physio
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Right Side
- to pulmonary System thruPulmonary Artery
Left Side
- to Systemic Circulation thruAorta
Tricuspid Valves = connects the
RA to the RV; 3 cusps Bicuspid/Mitral Valves =
connects the LA to the LV;
2 cusps
Semilunar Valve = Pulmonary
Artery carries deO2 blood from
RV to Lungs for oxygenation
Pulmonary Vein carries O2
blood from Lungs to LA
Superior & Inferior Vena Cava =
carries deO2 blood from the bodyto the RA
Semilunar Valve = Aorta
carries O2 blood from LV tosystemic circulation
In between your parietal and
visceral pericardium is a
serous fluid-filled pericardial
cavity which allows the heartto beat easily without friction.
LUB
(S1 - 1ST heart s
ound)
DUB
(S2- 2ND heart sound)
1. Closure of the AV
valves (atrioventricular
Tricuspid side
Mitral side
2. Closure of the
semilunar valves
(pulmonic and
aortic valves)
Arteries = carries O2blood
Veins = caries deO2 blood
Except for:
Pulmonary Artery
= carries deO2blood
Pulmonary Veins= carries O2blood
Pericarditis inflammation of
the pericardium results in a
decrease in the amount ofserous fluid which causes the
pericardial layers to rub
formin ainful adhesions.
CARDIOVASCULAR SYSTEM
THE HEART (The Pump)
HEART:
Location: Thorax,
mediastinum
Thus: Heart surgery alsocalled thoracic surgery
The Apex is pointed towards
yourleft hip and rests on thediaphragm, approximately at the level
of the fifth intercostal space. (This is
exactly where one would place astethoscope to count the heart rate for
an apical pulse)
The size of your heart is as big as yourfist
Coverings/layers:
Pericardium (covers the heart)
1. Parietal outer part, hard and fibrous2. Visceral inner part or heart wall, consist of:
a) epicardiumprotective layer, serous membrane
with connective tissue covered by epithelium
b) Myocardium - thickcardiac muscle which contractsc) Endocardium is a thin, glistening sheet of endothelium
that lines the 4 chambers; it contains elastic and
collagenous fibers as well as Purkinje fibers whichare specialized muscle fibers that conduct cardiac
impulses
Chambers:
2 Atria = Receiving blood
2 Ventricles = Discharging
blood
Septum = Wall Divisions
The heart valves open and close passively because of pressure
differences on either side of the valve. When pressure is greater behindthe valve, the leaflets are blown open and the blood flows through the
valve. However, when pressure is greater in front of the valve, the
leaflets snap shut and blood flow is stopped. The motion of a heart valve
is analogous to the motion of the front door of your house. The door,which only opens in one direction, opens and closes due to pressure on
the door.
Apex
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Although a tremendous amount of blood flows
through the chambers of the heart, this blood does
not nourish the heart. The heart is nourished byblood from the coronary circulation, a system of
arteries, capillaries and veins that brings blood to all
of the tissues of the heart. The graphic aboveidentifies arteries (red) supplying oxygenated blood
to the heart tissue, and veins (blue) removing
deoxygenated blood. Coronary artery disease is
associated with reduced blood flow to these vessels.
Normal heart sounds are caused by the closing of
heart valves. As valves snap shut, the walls of the
chambers and major arteries vibrate. We hear thesevibrations as two distinct sounds; LUB-DUB.
Left coronary artery:
anterior interventricular
artery - supplies blood to theinterventricular septum andanterior walls of both
ventricles
circumflex artery -
supplies blood to the leftatrium and the posterior
In valvular stenosis the valve flaps becomeincompetent, they become stiff, often because ofendocarditis (bacterial infection of the
endocardium). This forces the heart to contract more
vigorously than normal. The hearts workloadincreases, and ultimately the heart weakens and may
fail. Under such conditions the faulty valve is
replaced with a synthetic valve or a valve taken froma pig heart.
Are responsible for the unidirectional flow of blood (one direction)
Also responsible for yourheart sounds
BLOOD SUPPLY of the heart is via(coronary circulation):
1. First 2 branches of the aorta,
2. left and right coronary arteries
These arteries arise
from the base of the aorta
and encircle the heart inthe atrioventricular
groove.
From thearteries it
will
goto yourcapillary
networks
capilla
ry veins
coronary sinusdrains to atrium of the
heart.
Right coronary artery:
Posterior interventricular
artery - runs to the apex andsupplies blood to the posterior
ventricular walls
Marginal artery - suppliesblood to the myocardium of
the right side of the heart
Veins: Small, middle, and great cardiac veins
leading to coronary sinus
The myocardium needs a constant supply of
oxygen in order for the heart to continually
pump. Myocardium capillaries are branchesof cardiac veins which join to form the
coronary sinus, an enlarged vein which
empties into the right atrium.
* If any part of the heart muscle is
deprived of its blood supply
through interruption of bloodflow through the coronary
arteries and their branches, the
muscle tissue deprived of bloodcannot function and will die.
This is called myocardial
infarction (MI).
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NERVE SUPPLY of the heart: Medulla (cardiac center)
Vagus nerve help regulate heart activity; it lowers heart rate (parasympathetic)
o In contrast Sympathetic Nerve will increase HR and cardiac output
Conduction System: to electrical impulses it will create a contraction.SA Node
PHYSIOLOGY OF THE HEART
CARDIAC OUTPUT
The volume of blood ejected by each ventricle in one minute
CO = Stroke Volume (SV) X Heart Rate (HR)
Stroke Volume the amount of blood ejected by the left ventricle with each heartbeat
Preload the end diastolic filling volume of the ventricle, increases by increased returning volume to
the ventricle
Afterload the resistance to left ventricle ejection; increases by increased systemic arterial pressure
Heart Rate the number of heartbeats per minute; normal heart rate is 60 to 100 bpm
CARDIAC CYCLE
Each complete heartbeat consists of two phases; N = 0.8 Seconds
Systole the contraction phase; it is triggered by depolarization of cardiac muscle cells
Diastole the relaxation phase; immediately after depolarization is completed, the process reverses
itself, resulting in repolarization & a return to the resting state
LAB/DIAG TEST:
1. BLOOD CHEMISTRY
Cardiac Isoenzymes
Troponin T and I
These are contractile proteins of the myofibril
The cardiac isoforms are very specific for cardiac injury and are not present in serum from healthy
people
Current guidelines from the American College of Cardiology Committee state that cardiac troponins
are the preferred markers for detecting myocardial cell injury
Troponin I (cTnI) or T (cTnT) are the forms frequently assessed.
Rises 2 - 6 hours after injury
Peaks in 12 - 16 hours
cTnI stays elevated for 5-10 days, cTnT for 5-14 days
Creatine
Kinase (creatine phosphokinase)
This enzyme is found in heart muscle (CK-MB),
skeletal muscle (CK-MM), and brain (CK-BB).
Creatine kinase is increased in over 90% of
myocardial infarctions
However, it can be increased in muscle trauma,
physical exertion, postoperatively, convulsions,
delirium tremens and other conditions.
Time sequence after myocardial infarctionbegins to rise 4-6 hours
peaks 24 hours
returns to normal in 3-4 days
Myoglobin
Found in striated muscle
Damage to skeletal or cardiac muscle releases myoglobin into circulation
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Have false positives with skeletal muscle injury and renal failure.
Time sequence after myocardial infarction
Rises fast (2 hours) after myocardial infarction
Peaks at 6 - 8 hours
Returns to normal in 20 - 36 hours
Lactic Dehydrogenase
This enzyme is no longer used to diagnose myocardial infarction
Elevates after 24-48 hours
2. LIPID PROFILE:
A group of tests that are often ordered together to determine risk ofcoronary heart disease
They are tests that have been shown to be good indicators of whether someone is likely to have a heart attack
orstroke caused by blockage of blood vessels or hardening of the arteries (atherosclerois)
The lipid profile typically includes:
3. HEMATOLOGIC STUDIES
CBC
Coagulation Time
Prothrombin Time (PT) Partial Thromboplastin Time (PTT)
ESR
4. ELECTRO CARDIOGRAM (ECG) gives a graphic picture of your heart
5. STRESS TEST:
Could be exercise (treadmill or bicycle), or chemical
(Persantine, dobutamine)
Stress testing provides the doctor with information about
how the heart works during physical stress
During a stress test, you exercise (walk or run on atreadmill or pedal a bicycle) or are given a medicine to
make your heart work harder while heart tests are
performed
During these tests, your heart is monitored using images or
through dime-sized electrodes attached to your chest,
arms, or legs. You may be asked to breathe into a
special tube during the test. This will allow your doctor tosee how well youre breathing.
6. ECHOCARDIOGRAM:
Non-invasive recording of the cardiac structures using an ultrasound
Total Cholesterol Less than 200 mg/dL desirable
High density lipoprotein (HDL)- good cholesterol 30 - 75 mg/dL
Low density lipoprotein (LDL)
- bad cholesterolLess than 130 mg/dL desirable
Triglycerides (Male) Greater than 40 - 170 mg/dL
Triglycerides (Female) Greater than 35 - 135 mg/dL
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7. PHONOCARDIOGRAM noninvasive device to amplify & record heart sounds and murmurs
8. CARDIAC CATHETERIZATION
Invasive but most definitive test for diagnosis ofcardiac disease
Purpose:
oTo measure intracardic pressures & oxygen
levels in various parts of the heart
oWith injection of a dye, allows visualization ofthe heart chambers, blood vessels & course ofblood flow (angiography)
Procedure:
Right-Sided Catheterization
The catheter is inserted into an antecubital
vein & advanced into the vena cava, right
atrium, & right ventricle with furtherinsertion into the pulmonary artery
Left-Sided Catheterization
The catheter is inserted into a brachial orfemoral artery; the catheter is passed
retrograde up the aorta & into the left
ventricle
Pretest Nsg. Care:
Confirm that informed consent has been signed
Ask about allergies particularly to iodine if dyeis being used
Keep client NPO for 8-12 hours prior to test
Take baseline VS & monitor peripheral pulses
Inform client that a feeling of warmth &
fluttering sensation as catheter is passed is common Posttest Nsg. Care:
Assess circulation to the extremity used for catheter insertion
Post-procedure Position: Maintain the patient in a supine position for a
minimum of 4 hours this prevents hip flexion thereby limiting injury & promoting healing of the
catheter insertion site; HOB should be elevated but it should not exceed 20degrees
Check peripheral pulses, color, sensation of affected extremity every 15 minutes for 4 hours
If protocol requires, keep affected extremity straight for approximately 8 hours
Observe catheter insertion for swelling & bleeding; a sandbag or pressure dressing may be placed over
insertion site
Assess VS & report significant changes from baseline
9. AORTOGRAPHY
Injection of a radiopaque contrast medium into the aorta to visualize the aorta, valve
leaflets & major vessels on a movie film
Purpose: To determine & diagnose aortic valve incompetence, aneurysms
of the ascending aorta, abnormalities of major branches of the aorta
PreTest & PostTest Nsg Care similar to Cardiac Catheterization
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10. CORONARY ARTERIOGRAPHY
Visualization of coronary arteries by injection of radiopaque contrast dye &
recording on a movie film
Purpose: To evaluate heart disease & angina, location of areas of infarction &
extent of lesions, ruling out coronary artery disease in clients with myocardialdisease
Nursing Care similar to Cardiac Catheterization
11. CENTRAL VENOUS PRESSURE (CVP)
Obtained by inserting a catheter into the external jugular,antecubital or femoral vein & threading it into the vena cava
The catheter is attached to an IV infusion & water manometer by a
three way stopcock
Purposes:
Reveals right atrial pressure, reflecting alterations in the right
ventricular pressure
Provides information concerning blood volume & adequacy of
central venous return Provides IV route for drawing blood samples, administering
fluids or medication, & possibly inserting a pacing catheter
Normal Range: 4-10 cm H20; elevation indicates hypervolemia &
decreased level indicates hypovolemia
Nursing Care:
Ensure client is relaxed
Maintain zero point of manometer always at the level of right
atrium (midaxillary line)
Determine patency of catheter by opening IV line
Turn stopcock to allow IV solution to run into manometer to a level of 10-20 cm above expected pressure
reading Turn stopcock to allow IV solution to flow from manometer into catheter; fluid level in manometer
fluctuates with respiration; where water flow stops that is the CVP reading
Stop ventilatory assistance during measurement of CVP
After VP reading, return stopcock to IV infusion position (KVO rate)
Recommended