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Nursing 202 – Heart Failure Notes
1. Heart failure (HF) is closely associated with disorders such as chronic hypertension,
coronary artery disease, and diabetes.
A number of diseases that affect the heart may lead to HF, defined as the inability of
the heart to pump enough blood to meet the body’s metabolic needs. Controlling
chronic HTN, CAD, and diabetes can help prevent or slow the progress of HF.
2. The body attempts to compensate for heart failure by increasing cardiac output.
Heart failure may occur on the right, left, or both sides of the heart. The body attempts
to compensate for HF through ventricular hypertrophy, activation of the SNS,
increasing plasma volume and preload, and by secreting natriuretic peptides and other
neurohumoral substances.
3. Symptoms of heart failure occur when compensatory mechanisms fail to maintain
adequate cardiac output.
When decompensation occurs, signs and symptoms of HF manifest, such as dyspnea,
fatigue, coughing, and peripheral edema. Reasons for decompensation include
nonadherence with sodium or water restrictions, nonadherence with drug therapy or
additional injury to the heart from an MI. Drugs that slow the contractility of the
myocardium should be used cautiously in patients with HF.
4. The specific therapy for heart failure depends upon the clinical stage of the disease.
Two methods are used to classify HF. The NYHA model uses four functional classes
that depend upon the ability to perform physical activity with or without symptoms.
The ACC/AHA model uses four stages, which recognize the preventable nature of the
disorder.
5. Angiotensin-converting enzyme inhibitors are drugs of choice for heart failure.
Angiotensin-converting enzyme (ACE) inhibitors improve heart failure by reducing
peripheral resistance and blood volume. Clinical research has clearly demonstrated
reduced hospitalizations and increased survival when ACE inhibitors are administered
to patients with HF. Because of their effectiveness and their relatively low potential for
serious adverse effects, they have become first-line drugs in the treatment of HF.
Angiotensin receptor blockers are also effective, and are prescribed for patients unable
to tolerate ACE inhibitors.
6. Diuretics relieve symptoms of heart failure by reducing fluid overload and decreasing
blood pressure.
Diuretics produce few adverse effects and are often used in combination with other HF
drugs to reduce peripheral edema, pulmonary congestion, coughing, and dyspnea. Loop
diuretics such as furosemide are commonly used, due to their high efficacy. Thiazides
may be used to boost diuresis in patients exhibiting diuretic resistance. Although a
diuretic, spironolactone is primarily used for inhibiting the deleterious effects of
aldosterone on the myocardium.
7. Beta-adrenergic antagonists can dramatically reduce hospitalizations and increase the
survival of patients with heart failure.
Although beta-blockers decrease myocardial contractility, they also lower heart rate
and blood pressure, which are beneficial to reducing the symptoms of HF. When
administered properly, they have the potential to reduce the cardiac remodeling caused
by hyperactivation of the SNS. When treating clients with HF, they are always used in
combination with other drugs.
8. Vasodilators reduce symptoms of heart failure by reducing preload or afterload.
Direct vasodilators are effective at relaxing blood vessels, thus reducing preload or
afterload. Hydralazine and isosorbide dinitrate act synergistically to relieve pulmonary
congestion and other HF symptoms. Their use is limited by a high incidence of reflex
tachycardia and orthostatic hypotension.
9. Cardiac glycosides increase the force of myocardial contraction and were once drugs of
choice for heart failure.
Cardiac glycosides increase myocardial contractility. While effective at relieving
symptoms, they do not increase survival from HF. The large number of drug–drug
interactions and the potential for serious adverse effects such as dysrhythmias limit
their use to patients who are not responding adequately to ACE inhibitor therapy or to
HF patients with atrial fibrillation.
10. Phosphodiesterase III inhibitors and other positive inotropic agents are used for acute
decompensated heart failure.
Phosphodiesterase III inhibitors are a relatively new class of drugs used for the shortterm treatment of acute HF. They act by increasing contractility and reducing afterload.
While effective, they are only given IV and can produce potentially serious adverse
effects. Beta-adrenergic agonists such as dobutamine and dopamine may also be used
for acute HF to increase myocardial contraction and cardiac output.
11. Several novel approaches to therapy have resulted in new drugs for heart failure.
Human beta natriuretic peptide is a natural hormone secreted by the ventricles of
patients with HF. Through recombinant DNA technology, this hormone is now
available as nesiritide (Natrecor) for the treatment of acute, decompensated HF.