Download Assessment of Cardiovascular Function

Assessment of Cardiovascular
Function
Brunner 2012.
Chapter 26
S1—First Heart Sound
• Closure of the mitral and tricuspid valves
creates the first heart sound (S1), although
vibration of the myocardial wall also may
contribute to this sound.
• S1 ,is heard best at the apex of the heart .
• Its intensity increases when the valve leaflets
are made rigid by calcium in rheumatic heart
disease .
S2 Second Heart Sound
• Closing of the aortic and pulmonic valves
produces the second heart sound (S2 ).
• The splitting is more likely to be accentuated
on inspiration and to disappear on exhalation.
• (More blood is ejected from the right
ventricle during inspiration than during
exhalation.)
• S2 is heard loudest at the base of the heart.
• The aortic component of S2 is heard clearly in
both the aortic and pulmonic areas,and less
clearly at the apex.
• The pulmonic component of S2 , if present,
may be heard only over the pulmonic area.
Gallop Sounds
• Gallop sounds are very low-frequency sounds
and may be heard only with the bell of the
stethoscope placed very lightly against the
chest.
• They are heard best at the apex, although
occasionally, when emanating from the right
ventricle, they may be heard to the left of the
sternum.
Gallop Sounds
Murmurs.
• Murmurs are created by the turbulent flow of
blood.
• The causes of the turbulence may be a critically
arrowed valve,a malfunctioning valve that allows
regurgitant blood flow:
• a congenital defect of the ventricular wall, a
defect between the aorta and the pulmonary
artery, or an increased flow of blood through a
normal structure (eg, with fever, pregnancy,
hyperthyroidism).
Friction Rub.
• In pericarditis, a harsh, grating sound that can
be heard in both systole and diastole is called
a friction rub.
• It is caused by abrasion of the pericardial
surfaces during the cardiac cycle.
• A pericardial friction rub can be heard best
using the diaphragm of the stethoscope, with
the patient sitting up and leaning forward.
Cardiac Enzyme Analysis
• Enzymes are released from injured cells when
the cell membranes rupture.
• Lactic dehydrogenase(LDH) and its isoenzymes
also are analyzed in patients who have
delayed seeking medical attention, because
these blood levels rise and peak in 2 to 3 days,
much later than CK levels.
Myoglobin
• Myoglobin, an early marker of MI, is a heme protein
with a small molecular weight.
• This allows it to be rapidly released from damaged
myocardial tissue and accounts for its early rise, within
1 to 3 hours after the onset of an acute MI.
• Myoglobin peaks in 4 to 12 hours and returns to
normal in 24 hours.
• Myoglobin is not used alone to diagnose MI, because
elevations can also occur in patients with renal or
musculoskeletal disease.
• However, negative results are helpful in ruling out an
early diagnosis of MI.
troponin
• After myocardial injury, elevated serum
troponin I concentrations can be detected
within 3 to 4 hours; they peak in 4 to 24 hours
and remain elevated for 1 to 3 weeks.
• These early and prolonged elevations make
very early diagnosis of MI possible or allow for
late diagnosis if the patient has delayed
seeking treatment.
CHOLESTEROL LEVELS
• Cholesterol (normal level, less than 200
mg/dL) is a lipid required for hormone
synthesis and cell membrane formation.
• It is found in large quantities in brain and
nerve tissue.
• Two major sources of cholesterol are diet
(animal products) and the liver,where
cholesterol is synthesized.
…CHOLESTEROL LEVELS
• Elevated cholesterol levels are known to increase the
risk for CAD.
• LDLs (normal level, less than 130 mg/dL) are the
primary transporters of cholesterol and triglycerides
into the cell.
• One harmful effect of LDL is the deposition of these
substances in the walls of arterial vessels. Elevated LDL
levels are associated with a greater incidence of CAD.
• In people with known CAD or diabetes, the primary
goal for lipid management is reduction of LDL levels to
less than 100 mg/dL.
HDL(High Density Lipoprotein)
• HDLs (normal range in men, 35 to 65 mg/dL; in
women, 35 to 85 mg/dL) have a protective action.
• They transport cholesterol away from the tissue and
cells of the arterial wall to the liver for excretion.
• Therefore, there is an inverse relationship between
HDL levels and risk for CAD.
• Factors that lower HDL levels include smoking,
diabetes, obesity, and physical inactivity.
• In patients with CAD, a secondary goal of lipid
management is the increase of HDL levels to more than
40 mg/dL.
Triglycerides
• Triglycerides (normal range, 40 to 150 mg/dL),
composed of free fatty acids and glycerol, are
stored in the adipose tissue and are a source of
energy.
• Triglyceride levels increase after meals and are
affected by stress.
• Diabetes, alcohol use, and obesity can elevate
triglyceride levels.
• These levels have a direct correlation with LDL
and an inverse one with HDL.
SERUM ELECTROLYTE LEVELS
• Sodium, potassium, and calcium are ions that are
vital to cellular depolarization and repolarization.
• In addition, the serum sodium concentration
reflects relative fluid balance.
• Generally, hyponatremia (low sodium level)
indicates fluid excess, and hypernatremia (high
sodium level) indicates fluid deficit.
• On the ECG, hypomagnesemia lengthens the QT
interval, predisposing the patient to life
hreatening dysrhythmias.
Coagulation Studies
• Coagulation studies are routinely performed
before invasive procedures, such as cardiac
catheterization, electrophysiology testing, and
coronary or cardiac surgery.
Partial thromboplastin time (PTT)
• Partial thromboplastin time (PTT) and
activated partial thromboplastin time (aPTT)
measure the activity of the intrinsic pathway.
• The values of PTT and aPTT are used to assess
the effects of heparin therapy.
• Patients receiving heparin have their PTT or
aPTT levels maintained at 1.5 to 2.5 times
their baseline values (reference range, 25 to
38 seconds
Prothrombin time (PT)
• Prothrombin time (PT) measures the extrinsic pathway
activity and is used to monitor the effects of therapeutic
anticoagulation with warfarin (Coumadin).
• Laboratory results of PT also include the International
Normalized Ratio (INR) .
• The INR provides a standard method for reporting PT levels,
eliminating the variation of PT results from laboratory to
laboratory.
• The INR is maintained between 2.0 and 3.0 for patients with
deep vein thrombosis, pulmonary embolism, valvular heart
disease, or atrial fibrillation, and between 2.5 and 3.5 for
patients with mechanical prosthetic heart valve replacements.
CHEST X-RAY
AND FLUOROSCOPY
ELECTROCARDIOGRAPHY
Continuous Electrocardiographic
Monitoring
• HARDWIRE CARDIAC MONITORING
• TELEMETRY
• CONTINUOUS AMBULATORY
MONITORING(Holter monitor).
• TRANSTELEPHONIC MONITORING
CONTINUOUS AMBULATORY MONITORING(Holter monitor).
CARDIAC STRESS TESTING or Exercise
Tolerance Test(ETT)
• helps determine the following:
• (1) CAD, (2) cause of chest pain, (3) functional
capacity of the heart after an MI or heart
surgery, (4) effectiveness of antianginal or
antiarrhythmic medications, (5) dysrhythmias
that occur during physical exercise,and (6)
specific goals for a physical fitness program.
Contraindications
• Contraindications to stress testing include
severe aortic stenosis, acute myocarditis or
pericarditis, severe hypertension, suspected
left main CAD, HF, and unstable angina.
• Because complications associated with stress
testing can be life-threatening (MI, cardiac
arrest,HF, and severe dysrhythmias), testing
facilities must have staff and equipment ready
to provide advanced cardiac life support.
• NURSING INTERVENTIONS
ECHOCARDIOGRAPHY
Transesophageal Echocardiography
RADIONUCLIDE IMAGING
• Radionuclide imaging studies involve the use
of radioisotopes to evaluate coronary artery
perfusion noninvasively, to detect myocardial
ischemia and infarction, and to assess left
ventricular function.
• Thallium 201 (Tl 201) and technetium 99m (Tc
99m) are two of the most common
radioisotopes used in cardiac nuclear
medicine studies.
RADIONUCLIDE IMAGING
RADIONUCLIDE IMAGING
• As they decay, they give off small amounts of
energy in the form of gamma rays.
• When they are injected intravenously into the
bloodstream, the energy emitted by the
radioisotope can be detected by a gamma
scintillation camera positioned over the body.
CARDIAC CATHETERIZATION
• Cardiac catheterization is an invasive
diagnostic procedure in which radiopaque
arterial and venous catheters are introduced
into selected blood vessels of the right and
left sides of the heart.
• Catheter advancement is guided by
fluoroscopy
ANGIOGRAPHY
• Common sites for selective angiography are
the aorta, the coronary arteries, and the right
and left sides of the heart
HEMODYNAMIC MONITORING
• Central Venous Pressure Monitoring
• (0 to 8 mm Hg)
Pulmonary Artery Pressure Monitoring
• Normal pulmonary artery pressure is 25/9 mm
Hg, with a mean pressure of 15 mm Hg.
Intra-arterial Blood Pressure
Monitoring