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Heart failure affects more than 3 million
persons in the United States. HF is the condition in which the heart is unable to generate
a cardiac output sufficient to meet and maintain the metabolic requirements of the body,
either at rest or on demand.
Causes
The most frequent cause of HF is coronary artery disease. Hypertensive or valvular heart
disease and diseases in heart muscle are also common causes. Furthermore, HF can be
secondary to infectious, metabolic, endocrine, nutritional, or toxic causes (notably
alcohol and anthracyclines); rheumatic diseases; neuromuscular or autoimmune disorders; as
well as diseases characteized by accumulation of certain substances in the heart. For
example, heart failure due to hemochromatosisis characterized by the postion of iron in
heart muscle.
Types of HF
1. HF due to systolic dysfunction. This means that the heart cannot properly contract so
that, as a consequence, not enough blood can be pumped out.
2. HF due to diastolic dysfunction. This means that there is impaired filling and
decreased relaxation of the heart.
Symptoms
Symptoms of HF can include fatigue, reduced exercise capacity, and decreased
concentration or mental function, difficulties breathing when lying down flat (orthopnea),
difficulties breathing during exercise (exertional dyspnea), sudden difficulties breathing
at night (paroxysmal nocturnal dyspnea), abdominal bloating, nausea, and fluid retention
(ascites, edema). The New York Heart Association (NYHA) classification system is widely
used to categorize patients by symptoms, although it is not objective and therefore
subject to criticism. Class I patients have no symptoms with normal activities and no
limitation of their physical activity. Class II patients have symptoms of HF with slight
or moderate activity. Class III patients have marked limitation of activity but are
comfortable at rest. Class IV patients have symptoms of HF at rest—and the worst
prognosis.
Diagnosis
The greater the number of symptoms observed in a given patient, the more reliable is the
diagnosis of HF.
A. Diagnostic tests employed include:
1. An ECG is uesd to assess for signs of heart attack, arrhythmia (rhythm disturbances of
the heart), and other abnormalities which may be read in this exam. Nonspecific ECG
abnormalities which are not characteristic of any particular disease are common.
2. Chest X-rays are used.
3. Imaging techniques are employed to assess ventricular function.
4. Exercise testing. If patient is stable, exercise testing can provide objective evidence
of functional impairment or screen for coronary artery disease. Nuclear or stress
echocardiography techniques are employed if ECG is not interpretable.
Prognosis
Each of the following are examples of independent parameters suggesting a poor prognosis.
• Low ejection fraction (when the contractility of the heart is markedly decreased).
• Class IV heart failure has the highest mortality rate (30–50% mortality at 1
year).
• The amount of exercise a patient can do is low (age dependent).
• Rhythm disturbances
• Decreased sodium in blood serum
Treatment of Systolic HF
A patient with heart failure should visit a cardiologist at his or her practice. Typical
treatment methods include:
A. A diet consisting of sodium and water restriction.
B. Use of angiotensin-converting enzyme (ACE) inhibitors. This is the only therapy
that has actually been proven to improve prognosis in heart failure.
C. Use of digitalis to improve heart contractility.
D. Use of diuretics to relieve congestive symptoms by promoting excretion of excess sodium
and water.
E. Use of beta-blockers. Although previously it had been believed that beta-blockers are
contraindicated in the treatment of heart failure, recent data show that certain
beta-blockers are actually beneficial in the treatment. However, such treatment should
only be performed by an experienced cardiologist in the treatment of heart failure.
F. In severe cases, cardiac transplantation may be indicated.
Treatment of Diastolic HF
Diastolic HF is common and can be difficult to treat. The etiologies of coronary artery
disease and hypertension should be sought and treated, if present. A patient with heart
failure should visit a cardiologist at his or her practice. Typical treatment methods
include:
A. A diet consisting of sodium and water restriction.
B. Beta-blockers
C. Calcium channel blockers
D. ACE inhibitors
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