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RNSG 2331 EXAM 2 STUDY GUIDE
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RNSG 2331Exam #2 Med Surg Study Guide
Chapter 25 Assessment of Cardiovascular Function
1. Diastole – ventricular relaxation resulting ventricular filling
2. Systole – ventricular contraction resulting in ejection of blood from the ventricles into the
pulmonary artery and aorta
3. Preload – degree of stretch of the cardiac muscle fibers at the end of diastole
4. Afterload – the amount of resistance to ejection of blood from the ventricle
5. Contractility – ability of the cardiac muscle to shorten in response to an electrical impulse
6. Cardiac output – amount of blood pumped by each ventricle in liters per minute (CO =
HR x SV)
7. Ejection fraction – percentage of the end-diastolic blood volume ejected from the
ventricle with each heartbeat
8. Depolarization – electrical activation of a cell caused by the influx of sodium into the cell
while potassium exits the cell
9. Repolarization – return of the cell to resting state, caused by reentry of potassium into the
cell wall while sodium exists the cell
10. S1 – the first heart sound produced by closure of the av (mitral and tricuspid) valves
11. S2 – the 2nd heart sound produced by closure of the semilunar (aortic and pulmonic)
valves
The Anatomy of the Heart
Three layers:
o Endocardium = inner layer and lines the inside of the heart and valves
o Myocardium – middle layer, responsible for the pumping action (contraction)
Epicardium – the exterior layer
Heart Valves
o Atrioventricular valves = tricuspid and mitral
o Semilunar valves = pulmonic and aortic
Heart Chambers
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, Exam #2 Med Surg Study Guide
During diastole, the heart is in relaxation phase which allows the ventricles to fill
reparation for contraction
Systole, refers to contraction of the atria and the ventricles
Apical Impulse (point of maximal impulse [PMI]) is heard at the intersection of the
midclavicular line of the left chest wall and the 5th intercostal space
Function of the Heart
Sinoatrial (SA) node – the primary pacemaker of the heart
o in a normal resting adult heart has an inherent firing rate of 60 to 100 impulses per
minute: rate changes in response to metabolic demands of the body
Atrioventricular (AV) node – the secondary pacemaker of the heart
Cardiac output – refers to the total amount of blood ejected by one of the ventricles in
liters per minute
o Cardiac output in a resting adult 4 to 6 L/min
o CO=SV x HR
Stroke volume – the amount of blood ejected from one of the ventricles per heartbeat o
the average resting stroke volume is about 60 – 130 mL
Blood Pressure
A normal BP in adults is considered a systolic BP less than 120 mm Hg over a diastolic
BP less than 80 mm Hg
Hypertension – systolic BP that is consistently greater than 140 mm Hg or a diastolic BP
greater than 90 mm Hg
o Hypotension – an abnormally low systolic and diastolic BP lightheadedness or fainting
Pulse Pressure
Normally 30 – 40 mm Hg is an indicator of how well the patient maintains CO Pulse
Rate
Varies from a low of 50 bpm in healthy, athletic young adults and 100 bpm after
exercise/excitement
Heart Auscultation
Normal Heart Sounds
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, Exam #2 Med Surg Study Guide
S1 – the 1st heart sound
Tricuspid and mitral valve closure
S2 – the 2nd heart sound
Pulmonic and aortic valve closure
Abnormal Heart Sounds
S3 – 3rd heart sound
Heard early in diastole during the period of rapid ventricular filling as blood flows from
the atrium into a noncompliant ventricle
S4 – 4th heart sound
Occurs late in diastole, and is heard just before S1
Murmurs – are created by turbulent flow of blood in the heart
Diagnostics – Laboratory Tests
Cardiac Biomarker Analysis
The diagnosis of MI is made by evaluating the Hx and physical examination, the ECG,
and lab tests that measure serum cardiac biomarkers. The following substances leak into
the interstitial spaces of the myocardium and are carried by the lymphatic system into
general circulation which are then detected in serum blood samples in abnormally high
levels
Myocardial cells that become necrotic from prolonged ischemia or trauma release
specific enzymes:
Creatinine kinase [CK]
CK isoenzymes [CK-MB]
Proteins [myoglobin, troponin T, and troponin I]
Lipid Profile
Cholesterol, triglycerides, and lipoproteins are measured to evaluate a person’s risk of
developing CAD
Blood specimens for the lipid profile should be obtained after a 12-hour fast
Two major sources of cholesterol are diet (animal products) and the liver (where
cholesterol is synthesized)
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, Exam #2 Med Surg Study Guide
o LDLs – are the primary transporters of cholesterol and triglycerides into the cell
Normal: less than 160 mg/dL
One harmful effect of LDL is the deposition of these substances in the walls of arterial
vessels
o HDLs – have a protective action; they transport cholesterol away from the tissue and cells of
the arterial wall to the liver for excretion
Normal: Men 35–70mg/dL & women 35–85mg/dL
Factors that lower HDL levels smoking, diabetes, obesity, and physical inactivity
o Triglycerides – composed of free fatty acids and glycerol, are stored in the adipose tissue and
are a source of energy
Norm: 100 – 200 mg/dL Brain (B-type) Natriuretic Peptide
BNP is a neurohormone that helps regulate BP and fluid volume; secreted from the ventricles in
response to increased preload with resulting elevated ventricular pressure
o Greater than 100 pg./mL is suggestive of HF C-Reactive Protein
CPR is a protein produced by the liver in response to systemic inflammation; used to predict
CVD risk Homocysteine
An amino acid that is linked to the development of atherosclerosis because it can damage
the endothelial lining of arteries and promote thrombus formation
Indicative of CAD, stroke, and peripheral vascular disease -12- hour fast
Diagnostic Evaluation
Chest X-RAY
o Reveals cardiac and pericardial calcifications
Electrocardiography
o Diagnoses : Dysrhythmias, Conduction abnormalities, Chamber enlargement,
Myocardial ischemia, infarction, injury, Electrolyte disturbances
Cardiac Stress Test
Noninvasive ways to evaluate response to stress; normally, cardiac arteries dilate to four times
their usual diameter in response to increased metabolic demands for oxygen and nutrients
Atherosclerotic vessels dilate lessischemia
Abnormalities are likely to be detected during times of increased demand (stress)
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