* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Notes on CHF
Remote ischemic conditioning wikipedia , lookup
Electrocardiography wikipedia , lookup
Hypertrophic cardiomyopathy wikipedia , lookup
Arrhythmogenic right ventricular dysplasia wikipedia , lookup
Lutembacher's syndrome wikipedia , lookup
Coronary artery disease wikipedia , lookup
Cardiac contractility modulation wikipedia , lookup
Heart failure wikipedia , lookup
Management of acute coronary syndrome wikipedia , lookup
Cardiac surgery wikipedia , lookup
Heart arrhythmia wikipedia , lookup
Dextro-Transposition of the great arteries wikipedia , lookup
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.