Congestive heart failure overview
| Congestive Heart Failure Microchapters |
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Pathophysiology |
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Differentiating Congestive heart failure from other Diseases |
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Diagnosis |
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Treatment |
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Medical Therapy: |
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Surgical Therapy: |
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ACC/AHA Guideline Recommendations
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Specific Groups: |
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Congestive heart failure overview On the Web |
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Directions to Hospitals Treating Congestive heart failure overview |
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Risk calculators and risk factors for Congestive heart failure overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Saleh El Dassouki, M.D. [2]
Overview of Congestive Heart Failure
Heart failure is any condition of the heart that results in the inability of the heart to meet the demands of circulation causing insufficient blood flow. It is also defined as a complex clinical syndrome due to abnormalities of the cardiac structure and/or the function that impairs the left ventricle from filling with or ejecting blood.
Heart failure is not synonymous with cardiomyopathy or left ventricular dysfunction, as these are terms used to describe a structural or functional abnormality that could lead to heart failure. Heart failure is as clinical syndrome characterized by specific symptoms (dyspnea and fatigue) and signs(rales) upon physical examination. There is no single test to diagnose heart failure. It is largely a clinical diagnosis based on careful patient history review and physical examination.
Pathophysiology
Heart failure can result from an abnormality of any one of the anatomical structures of the heart; the pericardium, the myocardium, the endocardium, the valvular structures or the great vessels. Heart failure was once thought to be secondary to a depressed left ventricular ejection fraction. However, studies have shown that approximately 50% of patients who are diagnosed with heart failure have a normal ejection fraction (diastolic dysfunction). Patients may be broadly classified as having heart failure with depressed left ventricular ejection fraction (systolic dysfunction) or normal/preserved ejection fraction (diastolic dysfunction). Systolic and diastolic dysfunction commonly occur in conjunction with each other.
Diagnosis
Symptoms
The classic symptoms of heart failure include dyspnea, fatigue, and fluid retention.
Patients with heart failure present in different ways. Some patients present with exercise intolerance but show little evidence of congestion or edema. Other patients present with mild symptoms of edema and pulmonary congestion.
Treatment
General Measures:
Because heart failure is a clinical syndrome that is the end result of multiple heart diseases, the following measures are important:
- Treat basic cardiac disease such hypertension, improve myocardial perfusion and perform surgery for stenotic or leaking heart valves.
- Treat exacerbating conditions such as pneumonia, arrhythmia, hypokalemia.
- Restrict sodium intake.
Medications:
- Diuretics: Diuretics can reduce volume overload and reduce shortness of breath and edema. There are three kinds of diuretics, loop diuretics, thiazides and potassium-sparing diuretics. Given the risk of hypo or hyperkalemia, the blood level of electrolyes should be checked regularly.
- Angiotensin converting enzyme inhibitors (ACEI): Angiotensin converting enzyme inhibitors (ACEI) are widely used in cardiovascular diseases. This includes a large group of drugs, such as Enalapril (Vasotec/Renitec), Ramipril (Altace/Tritace/Ramace/Ramiwin), Quinapril (Accupril), Perindopril (Coversyl/Aceon), Lisinopril (Lisodur/Lopril/Novatec/Prinivil/Zestril) and Benazepril (Lotensin). They can improve symptoms and prognosis of heart failure in several ways including afterload reduction and favorable ventricular remodeling. Usual side effects include dry cough and angioedema. Patients who can not tolerate cough are often switched to an angiotensin II receptor antagonist. Patients with bilateral renal artery stenosis or severe renal impairment are not appropriate for angiotensin converting enzyme inhibitor (ACEI).
- Angiotensin II receptor antagonist: These type of drugs can block the activation of angiotensin II AT1 receptors. Blockade of AT1 receptors directly causes vasodilation, reduces secretion of vasopressin, reduces production and secretion of aldosterone. Because angiotensin II receptor antagonists do not inhibit the breakdown of bradykinin or other kinins, and are thus only rarely associated with the persistent dry cough and/or angioedema that limit ACE inhibitor therapy. Usual used drugs in heart failure are Candesartan, Valsartan, Telmisartan, Losartan, Irbesartan, and Olmesartan.
- Beta blockers: Beta blockers can reduce heart rate which will lower the myocardial energy expenditure and then prolong the diastolic filling and lengthen coronary perfusion. It can also improve the ejection fraction of the heart and decrease the toxicity of catecholamines on the myocardium. Clinical trials show Bisoprolol, Carvedilol and sustained-release Metoprolol are specifically indicated as adjuncts to standard ACE inhibitor and diuretic therapy in congestive heart failure. Patients with asthma, severe conduction block or severe heart failure may not be appropriate candidates for beta blocker therapy.
- Digitalis: Digitalis can strengthen the contractility of the heart. But because the pharmacokinetics of digoxin are complex, and the toxic levels are only slightly higher than therapeutic levels, digoxin should be used judiciously under the close supervision of a cardiologist.
Percutaneous coronary intervention (PCI):
Coronary artery disease (CAD) and impaired blood flow to the heart is one of the main causes of heart failure. Removing the blockages in the coronary arteries can improve overall heart function, which may improve or resolve heart failure symptoms. The procedure is usually performed in the cardiac catherization lab. A catheter, a very small tube with a tiny deflated balloon on the end, is inserted through an incision in the groin area and pushed through to the diseased artery. Then the balloon is inflated to push open the artery. The balloon is removed once the artery has been fully opened. A stent may be placed during the procedure to keep the blood vessel open. Clinical trials have demonstrated that percutaneous coronary intervention (PCI) is a very effective and safe procedure to reopen blocked vessels and can improve a patient's symptoms.
Left ventricular assist device (LVAD):
The left ventricular assist device (LVAD) is a mechanical pump-type device that can help maintain the pumping ability of a heart unable to effectively work on its own. One typical type of LVAD will have a tube going into the left ventricle that pulls blood from the ventricle into a pump. The pump then ejects blood into the aorta. LVADs are typically used for weeks to months as a "bridge" to more definitive therapy rather than a final or "destination" therapy.
Heart transplantation
Heart transplant may be the only effective treatment option for patients with severe, progressive heart failure that can not be helped by medications, dietary and lifestyle changes. During a heart transplant procedure, the surgeons connect the patient to a heart-lung machine, which takes over the functions of the heart and lungs. Then the surgeons remove the diseased heart and replace it with the donor heart. Finally, the major blood vessels are reconnected and the new heart is ready to work. The outlook for people with heart transplants is good during the first few years after the transplant. Over 85 percent of patients live for more than a year after their operations.