2. 2
Definition:
Congestive heart failure is a clinical syndrome
that results from the heart's inability to pump
the amount of oxygenated blood necessary to
meet the metabolic requirements of the body.
Pathophysiologv / Etiology:
.
1. Cardiac compensatory mechanisms
(increases in heart rate,
vasoconstriction, and heart enlargement) occur to
assist the failing heart.
a. These mechanisms are able to "compensate" for
the heart's inability to pump effectively and
maintain sufficient blood flow to organs and tissue
at rest.
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b.Physiologic stressors that increase the workload of
the heart (exercise, infection) may cause these
mechanisms to fail and precipitate the "clinical
syndrome" associated with a failing heart
(elevated ventricular/atrial pressures, sodium
and water retention, decreased cardiac output,
circulatory and pulmonary congestion).
c. The compensatory mechanisms themselves
may hasten the onset of failure as they increase
afterload and cardiac work.
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Caused by disorders of heart muscle resulting
in decreased contractile
properties of the heart; coronary heart
disease leading to myocardial infarction;
hypertension; valvular heart disease;
congenital heart disease; cardiomyopathies;
dysrhythmias.
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Other causes include:
1. Pulmonary embolism; chronic lung disease
2. Hemorrhage and anemia
3. Anesthesia and surgery
4. Transfusions or infusions
5. Increased body demands (fever, infection, pregnancy,
arteriovenous fistula)
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6. Drug-induced
7. Physical and emotional stress
8. Excessive sodium intake
Clinical Manifestations:
Initially there may be isolated left ventricular
failure, but in time, the right ventricle fails
because of the additional workload. Combined
left and right ventricular failure is common.
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Left-sided Heart Failure (Forward Failure)
1. Congestion occurs mainly in the lungs from
backing up of blood into
pulmonary veins and capillaries
a. Shortness of breath, dyspnea on exertion,
paroxysmal nocturnal dyspnea (due to re-
absorption of dependent edema that has
developed during day), orthopnea, pulmonary
edema
b. Cough—may be dry, unproductive; often
occurs at night
2. Insomnia, restlessness
3. Tachycardia S3 ventricular gallop
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4. Fatigability from low cardiac
output, nocturia, insomnia, dyspnea, catabolic
effect of chronic failure
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B. Right-sided Heart Failure (Backward Failure)
Signs and symptoms of elevated pressures and
congestion in systemic veins and capillaries:
1. Edema of ankles; unexplained weight gain (pitting
edema is obvious
only after retention of at least 4.5 kg [10 pounds] of
fluid).
2. Liver congestion—may produce upper abdominal
pain
3. Distended neck veins
4. Weakness
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5. Abnormal fluid in body cavities
(pleural space, abdominal cavity)
from hepatic and visceral
engorgement
6. Nocturia—diuresis occurs at night
with rest and improved cardiac output
7. Anorexia and nausea
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C. Cardiovascular Findings in Both Types
1. Cardiomegaly (enlargement of the heart)—
detected by physical
examination and chest x-ray
2. Ventricular gallop—evident on
auscultation; ECG
3. Rapid heart rate
4. Development of pulsus alternans
(alternation in strength of beat)
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Diagnostic Evaluation:
1. ECG may show ventricular hypertrophy, strain
2. Echocardiography may show ventricular
hypertrophy, dilation of
chambers, abnormal wall motion
3. Chest x-ray--may show cardiomegaly, pleural
effusion, and vascular
congestion
4. ABG studies may show hypoxemia
due to pulmonary vascular congesion
5. Liver function studies—may be altered
because of hepatic congestion
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Management :
Treatment is directed at eliminating excessive
accumulation of body water, increasing the
force and efficiency of myocardial contraction
and reducing the workload of the heart. These
goals are achieved through promoting rest
and administering pharmacologic agents.
A. Diuretics
Eliminate excess body water and decrease ventricular
pressures
A low-sodium diet and fluid restriction complement this
therapy
Some diuretics may have slight vasodilator
properties.
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B. Positive Inotropic Agents
1. Increase the heart's ability to pump more
effectively by improving
the contractile force of the muscle
2. Digoxin (Lanoxin) may only be effective in
severe cases of failure
3. Dopamine (Intropin) also improves renal
blood flow in low dose range
4. Dobutamine (Dobutrex)
5. Amrinone (Nucor) is a potent
vasodilators.
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C. Vasodilator Therapy
1. Decreases the workload of the heart by
dilating peripheral vessels.
2. By relaxing capacitance vessels (veins and
venules), vasodilators
reduce ventricular filling pressures (preload)
and volumes.
3. By relaxing resistance vessels
(arterioles), vasodilators can reduce
impedance to left ventricular ejection and
improve stroke volume.
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Vasodilators used in congestive heart failure:
1. Nitrates such as nitroglycerin (Tridil), isosorbide
dinitrate (Isordil), nitroglycerin ointment
(Nitrobid)—predominantly dilate systemic veins
2. Hydralazine (Apresoline) predominantly
affects arterioles; reduces arteriolar ton
3. Prazosin (Minipress) balanced effects on both
arterial and venous circulation
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D. Angiotensin-Converting Enzyme Inhibitors
(ACE Inhibitors)
1. Inhibit the adverse effects of angiotensin II
(potent vasoconstrictor)
2. Decreases left ventricular after load with a
subsequent decrease in heart rate associated
with heart failure, thereby reducing the
workload of the heart and increasing cardiac
output
3. Captopril (Capoten) and enalapril
(Vasotec) are commonly used.
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E. Heart Transplantation
It is used in advanced heart failure.
Complications:
1. Intractable or refractory heart failure—patient
becomes progressively refractory to therapy (does
not yield to treatment)
2. Cardiac dysrhythmias
3. Myocardial failure
4. Digitalis toxicity from decreased renal function ,
potassium depletion, etc.
5. Pulmonary infarction; pneumonia; emboli
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Nursing Assessment:
1. Obtain history of symptoms, limits of
activity, and response to rest.
2. Assess peripheral arterial pulses; note
quality, character; assess
heart, and blood pressure rhythm and rate.
3. Inspect/palpate precordium for lateral
displacement of point of
maximum impulse.
4. Identify sleeping patterns and sleep aids
commonly used by patient.
