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Outermost Pericardium
Innermost Pericardium
Parietal
Visceral (epicardium)
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Pericardial space holds how much fluid?
5-20mL
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Surface of heart =
Epicardium
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Middle layer of heart=
Myocardium
contracting muscle of the heart--conduction system here
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Inner layer of the heart=
lines inside heart's chambers and great vessels
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What prevents blackflow during contraction--flaps
Chordae tendineae
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faster heart rate=
- less time for filling
- cardiac output decreases
- increase in O2 consumption
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Intrinsic rates
- SA node= 60-100 bpm
- AV node= 40-60 bpm
- Ventricles= 20-40 bpm
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Diastole
ventricular filling and ventricles relaxed
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Atrial Kick
toward end of diastole, atria contract--pumping additional blood to ventricle
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Ventricular systole
- ventricles contract==blood ejected pulmonary and systemic
- 60-100 x/min
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Cardiac output
amt bl pumped by left ventricle in 1 min
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Stroke volume
- amt bl ejected from heart with each contraction
- 70mL adult
Calculation CO: multiply stroke vol X HR
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P wave
SA node inpulse and atrial contraction/depolarization
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PR interval
Time for impulse travel from SA to AV and bundle branches
Time: 0.12-0.20 sec
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QRS:
- ventricular depolarization
- 0.06-0.10
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ST segment
period from end QRS to begin T wave and norm isoelectric
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T wave
ventricular repolarization
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QT interval
beginning QRS to end of T wave; time for ventricular depolarization and repolarization
Time: 0.32- 0.44 sec
A lot of drugs affect QT interval
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Cardiac Output AVE adult
4-8L/min
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Cardiac output determined by 4 factors
- HR
- Preload (affected by venous return)-- Hypervolemia and fluid overload increases preload
- Afterload (htn, vasocontriction)-- overtime hypertrophy of left ventricle
- Contractility-- poor contractility= decreased stroke vol
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Election fraction
- % bl in ventricle ejected with each contraction
- affected by preload, afterload, and contractility
- norm is 65%
- (measure w/ cardiac cath)
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Lipid Profile: total cholesterol
triglicerides
HDL
LDL
purpose?
fasting?
- evaluate risk for atherosclerosis and coronary heart disease
- must be fasting for 12 hours
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C-reactive protein
purpose?
- <0.5
- measure inflammation and help predict CHF
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Serum cardiac markers: Creatine phosphokinase (CK or CPK): male--female
CK-MB
cTnT
cTn1
purpose?
- male-30-180
- female-10-70
- ck mb- 0-6%
- ctnt- <0.2
- ctn1-<0.5
- sensitive indicators of heart damage
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serum cardiac hormones: atrial cardiac factor or hormone
B-type natiuretic peptide(BNP)
purpose?
fast?
- 20-27
- <100
- Increase bl levels indicate heart failure
- must fast
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Transthoracic echocardiogram (TTE)
computer converts impulses to an image of heart walls, chambers, and their movements
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Transesophageal echocardiogram (TEE)
gives more direct view of heart by avoiding chest wall
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stress echocardiogram
combines resting, TTE, exercise on a treadmill or bike and ECG monitoring, and a TTE after exercise to evaluate effect of exercise on cardiac function
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Multigated Acuisition (MUGA) scan
- eval ht sixe, vent wall motion, and ejection fraction--eject isotope IV
- (more in notes)
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Exercise perfusion imaging or stress test
- eval myocardial perfusion during exercise
- (more in notes)
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tunica intima
innermost, slick surface, assist bl flow
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tinica media/middle
- smooth muscle, thicker and more elastic in arteries than veins
- allows arteries to expand and contract-maintain bl flow to capillaries between ht beats
- major factor in BP
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tunica adventitia
- outermost
- connective tissue protects and anchors vessel
- thicker in veins than arteries
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Blood pressure regulated by:
cardiac output and HR
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When CBC is down:
rheumatic ht disease and contitions char by inadequate tissue oxygenation
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When HCT is up
vascular volume depletion
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hypokalemia
hyperkalemia
- cardiac electrical instability goes up, ventricular dysrythmias and higher risk or dig toxicity
- higher risk for asystole (flat line) and vent dystrhythmias
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Na+
decrease in HF=h2o excess
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Ca+
- decrease with vent dysrhythmias, prolonged QT and cardiac arrest
- decrease with cardiac arrest
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Mg+
- low: v tach or v fib
- high: muscle weakness, hypotension, brady and prolonged PR
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Ankle-brachial index
- non invasive- highly indicative atherosclerosis
- BP cuffs placed at intervals on extremity
- divide systolic pressure at ankle by brachal systolic pressure
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each small box=
5 small boxes=
5 large boxes=
30 large boxes=
- 0.04 sec
- 0.2 sec
- 1 full sec
- 60 sec
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PR less than 0.12
impulse did not follow normal conduction pathway; rapis atrial rate
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PR more than 0.2 sec
disease process may be affecting cardiac conduction pathway- slowing it down/blocking; heart block
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NSR (normal sinus rhythm) usually 60-100--changes from normal affect:
pumping ability and tissue perfusion
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Dysthythmia can affect two things:
cardiac output and tissue perfusion
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