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Heart failure (HF), often referred to as congestive heart failure (CHF), occurs when the heart is unable to pump sufficiently to maintain blood flow to meet the body's needs. The terms chronic heart failure (CHF) or congestive cardiac failure (CCF) are often used interchangeably with congestive heart failure. Signs and symptoms commonly include shortness of breath, excessive tiredness, and leg swelling.〔 The shortness of breath is usually worse with exercise, while lying down, and may wake the person at night. A limited ability to exercise is also a common feature.〔 Common causes of heart failure include coronary artery disease including a previous myocardial infarction (heart attack), high blood pressure, atrial fibrillation, valvular heart disease, excess alcohol use, infection, and cardiomyopathy of an unknown cause.〔 These cause heart failure by changing either the structure or the functioning of the heart.〔 There are two main types of heart failure: ''heart failure due to left ventricular dysfunction'' and ''heart failure with normal ejection fraction'' depending on if the ability of the left ventricle to contract is affected, or the heart's ability to relax.〔 The severity of disease is usually graded by the degree of problems with exercise.〔 Heart failure is not the same as myocardial infarction (in which part of the heart muscle dies) or cardiac arrest (in which blood flow stops altogether). Other diseases that may have symptoms similar to heart failure include obesity, kidney failure, liver problems, anemia and thyroid disease. The condition is diagnosed based on the history of the symptoms and a physical examination with confirmation by echocardiography.〔 Blood tests, electrocardiography, and chest radiography may be useful to determine the underlying cause.〔 Treatment depends on the severity and cause of the disease.〔 In people with chronic stable mild heart failure, treatment commonly consists of lifestyle modifications such as stopping smoking,〔 physical exercise, and dietary changes, as well as medications.〔 In those with heart failure due to left ventricular dysfunction, angiotensin converting enzyme inhibitors or angiotensin receptor blockers along with beta blockers are recommended. For those with severe disease, aldosterone antagonists, or hydralazine plus a nitrate may be used.〔 Diuretics are useful for preventing fluid retention.〔 Sometimes, depending on the cause, an implanted device such as a pacemaker or an implantable cardiac defibrillator may be recommended.〔 In some moderate or severe cases cardiac resynchronization therapy (CRT) may be suggested or cardiac contractility modulation may be of benefit. A ventricular assist device or occasionally a heart transplant may be recommended in those with severe disease despite all other measures. Heart failure is a common, costly, and potentially fatal condition.〔 In developed countries, around 2% of adults have heart failure and in those over the age of 65, this increases to 6–10%.〔 In the year after diagnosis the risk of death is about 35% after which it decreases to below 10% each year.〔 This is similar to the risks with a number of types of cancer.〔 In the United Kingdom the disease is the reason for 5% of emergency hospital admissions.〔 Heart failure has been known since ancient times with the Ebers papyrus commenting on it around 1550 BCE. ==Terminology== Heart failure is a physiological state in which cardiac output is insufficient to meet the needs of the body and lungs. The term "congestive heart failure" is often used as one of the common symptoms is swelling or water retention. Heart failure is divided into two different types: heart failure due to reduced ejection fraction (also known as heart failure due to left ventricular systolic dysfunction or systolic heart failure) and heart failure with preserved ejection fraction (HFpEF) also known as diastolic heart failure or heart failure with normal ejection fraction.〔〔 Heart failure with reduced ejection fraction occurs when the ejection fraction is less than 40%. In diastolic heart failure, the heart muscle contracts well but the ventricle does not fill with blood well in the relaxation phase.〔 Ejection fraction is the proportion of blood pumped out of the heart during a single contraction.〔(【引用サイトリンク】url=http://www.hrsonline.org/Patient-Resources/The-Normal-Heart/Ejection-Fraction#axzz31jSSC7Uo )〕 It is given as a percentage with the normal range being between 50 and 75%.〔 The term "acute" is used to mean rapid onset, and "chronic" refers to long duration. Chronic heart failure is a long term condition, usually kept stable by the treatment of symptoms. Acute decompensated heart failure is a worsening of chronic heart failure symptoms which can result in acute respiratory distress. High-output heart failure can occur when there is an increased cardiac output. The circulatory overload caused, can result in an increased left ventricular diastolic pressure which can develop into pulmonary congestion (pulmonary edema). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「heart failure」の詳細全文を読む スポンサード リンク
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