Heart Failure

Heart Failure

Heart failure (HF) is a condition in which a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to meet the body's needs. It should not be confused with cardiac arrest or myocardial infarction (see ''Terminology'').

Common causes of heart failure include myocardial infarction and other forms of ischemic heart disease, hypertension, valvular heart disease and cardiomyopathy. Heart failure can cause a large variety of symptoms such as shortness of breath (typically worse when lying flat, which is called orthopnea), coughing, ankle swelling and reduced exercise capacity. Heart failure is often undiagnosed due to a lack of a universally agreed definition and challenges in definitive diagnosis. Treatment commonly consists of lifestyle measures (such as decreased salt intake) and medications, and sometimes devices or even surgery.

Heart failure is a common, costly, disabling and deadly condition.

Mostly due to costs of hospitalization, it is associated with a high health expenditure; costs have been estimated to amount to 2% of the total budget of the National Health Service in the United Kingdom, and more than $35 billion in the United States.

Heart failure is associated with significantly reduced physical and mental health, resulting in a markedly decreased quality of life.

With the exception of heart failure caused by reversible conditions, the condition usually worsens with time. Although some patients survive many years, progressive disease is associated with an overall annual mortality rate of 10%.

  • Heart Failure Terminology
  • Heart Failure Classification
  • Heart Failure Symptoms
  • Heart Failure Causes
  • Heart Failure Pathophysiology
  • Heart Failure Diagnosis
  • Heart Failure Management
  • Heart Failure Prognosis

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Heart Failure" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Heart Failure Terminology

Heart failure is a global term for the physiological state in which cardiac output is insufficient for the body's needs.

This occurs most commonly when the cardiac output is low (often termed "congestive heart failure").

In contrast, it may also occur when the body's requirements for oxygen and nutrients are increased, and demand outstrips what the heart can provide, (termed "high output cardiac failure") . This can occur in the context of severe anemia, Gram negative septicaemia, beriberi (vitamin B1/thiamine deficiency), thyrotoxicosis, Paget's disease, arteriovenous fistulae or arteriovenous malformations.

Fluid overload is a common problem for people with heart failure, but is not synonymous with it. Patients with treated heart failure will often be euvolaemic (a term for normal fluid status), or more rarely, dehydrated.

Doctors use the words "acute" to mean of rapid onset, and "chronic" of long duration. Chronic heart failure is therefore a long term situation, usually with stable treated symptomatology.

Acute decompensated heart failure, which should just describe sudden onset HF, is also used to describe exacerbated or decompensated heart failure, referring to episodes in which a patient with known chronic heart failure abruptly develops symptoms.

There are several terms which are closely related to heart failure, and may be the cause of heart failure, but should not be confused with it:

  • Cardiac arrest, and asystole both refer to situations in which there is ''no'' cardiac output at all. Without urgent treatment, these result in sudden death.
  • Heart attack refers to a blockage in a coronary (heart) artery resulting in heart muscle damage.
  • Cardiomyopathy refers specifically to problems within the heart muscle, and these problems usually result in heart failure. Ischemic cardiomyopathy implies that the cause of muscle damage is coronary artery disease. Dilated cardiomyopathy implies that the muscle damage has resulted in enlargement of the heart. Hypertrophic cardiomyopathy involves enlargement and ''thickening'' of the heart muscle.
  • Heart Failure
  • Heart Failure Classification
  • Heart Failure Symptoms
  • Heart Failure Causes
  • Heart Failure Pathophysiology
  • Heart Failure Diagnosis
  • Heart Failure Management
  • Heart Failure Prognosis

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Heart Failure" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Heart Failure Classification

There are many different ways to categorize heart failure, including:

  • the side of the heart involved, (left heart failure versus right heart failure)
  • whether the abnormality is due to contraction or relaxation of the heart (systolic dysfunction vs. diastolic dysfunction)
  • whether the problem is primarily increased venous back pressure (behind) the heart, or failure to supply adequate arterial perfusion (in front of) the heart (backward vs. forward failure)
  • whether the abnormality is due to low cardiac output with high systemic vascular resistance or high cardiac output with low vascular resistance (low-output heart failure vs. high-output heart failure)
  • the degree of functional impairment conferred by the abnormality (as in the NYHA functional classification)

''Functional'' classification generally relies on the New York Heart Association Functional Classification. The classes (I-IV) are:

  • Class I: no limitation is experienced in any activities; there are no symptoms from ordinary activities.
  • Class II: slight, mild limitation of activity; the patient is comfortable at rest or with mild exertion.
  • Class III: marked limitation of any activity; the patient is comfortable only at rest.
  • Class IV: any physical activity brings on discomfort and symptoms occur at rest.

This score documents severity of symptoms, and can be used to assess response to treatment. While its use is widespread, the NYHA score is not very reproducible and doesn't reliably predict the walking distance or exercise tolerance on formal testing.

In its 2001 guidelines, the American College of Cardiology/American Heart Association working group introduced four stages of heart failure:

  • Stage A: Patients at high risk for developing HF in the future but no functional or structural heart disorder;
  • Stage B: a structural heart disorder but no symptoms at any stage;
  • Stage C: previous or current symptoms of heart failure in the context of an underlying structural heart problem, but managed with medical treatment;
  • Stage D: advanced disease requiring hospital-based support, a heart transplant or palliative care.

The ACC staging system is useful in that Stage A encompasses "pre-heart failure" - a stage where intervention with treatment can presumably prevent progression to overt symptoms. ACC stage A does not have a corresponding NYHA class. ACC Stage B would correspond to NYHA Class I. ACC Stage C corresponds to NYHA Class II and III, while ACC Stage D overlaps with NYHA Class IV.

Diagnostic criteria

No system of diagnostic criteria has been agreed as the gold standard for heart failure. Commonly used systems are the "Framingham criteria" (derived from the Framingham Heart Study), the "Boston criteria", the "Duke criteria", and (in the setting of acute myocardial infarction) the "Killip class".

  • Heart Failure
  • Heart Failure Terminology
  • Heart Failure Symptoms
  • Heart Failure Causes
  • Heart Failure Pathophysiology
  • Heart Failure Diagnosis
  • Heart Failure Management
  • Heart Failure Prognosis

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Heart Failure" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Heart Failure Symptoms

Symptoms

Heart failure symptoms are traditionally and somewhat arbitrarily divided into "left" and "right" sided, recognizing that the left and right ventricles of the heart supply different portions of the circulation. However, heart failure is not exclusively ''backward failure'' (in the part of the circulation which drains to the ventricle).

There are several other exceptions to a simple left-right division of heart failure symptoms. Left sided ''forward'' failure overlaps with right sided ''backward'' failure. Additionally, the most common cause of right-sided heart failure is left-sided heart failure. The result is that patients commonly present with both sets of signs and symptoms.

Left-sided failure

''Forward'' failure of the left ventricle causes congestion of the pulmonary vasculature, and so the symptoms are predominantly respiratory in nature. Forward failure can be subdivided into failure of the left atrium, the left ventricle or both within the left circuit. The patient will have dyspnea (shortness of breath) on exertion (''dyspnée d'effort'') and in severe cases, dyspnea at rest. Increasing breathlessness on lying flat, called orthopnea, occurs. It is often measured in the number of pillows required to lie comfortably, and in severe cases, the patient may resort to sleeping while sitting up. Another symptom of heart failure is paroxysmal nocturnal dyspnea also known as "cardiac asthma", a sudden nighttime attack of severe breathlessness, usually several hours after going to sleep. Easy fatigueability and exercise intolerance are also common complaints related to respiratory compromise.

Compromise of left ventricular ''forward'' function may result in symptoms of poor systemic circulation such as dizziness, confusion and cool extremities at rest.

Right-sided failure

''Backward'' failure of the right ventricle leads to congestion of systemic capillaries. This helps to generate excess fluid accumulation in the body. This causes swelling under the skin (termed peripheral edema or anasarca) and usually affects the dependent parts of the body first (causing foot and ankle swelling in people who are standing up, and sacral edema in people who are predominantly lying down). Nocturia (frequent nighttime urination) may occur when fluid from the legs is returned to the bloodstream while lying down at night. In progressively severe cases, ascites (fluid accumulation in the abdominal cavity causing swelling) and hepatomegaly (enlargement of the liver) may develop. Significant liver congestion may result in impaired liver function, and jaundice and even coagulopathy (problems of decreased blood clotting) may occur.

Signs

Left-sided failure

Common respiratory signs are tachypnea (increased ''rate'' of breathing) and increased ''work'' of breathing (non-specific signs of respiratory distress). Rales or crackles, heard initially in the lung bases, and when severe, throughout the lung fields suggest the development of pulmonary edema (fluid in the alveoli). Cyanosis which suggests severe hypoxemia, is a late sign of extremely severe pulmonary edema.

Additional signs indicating left ventricular failure include a laterally displaced apex beat (which occurs if the heart is enlarged) and a gallop rhythm (additional heart sounds) may be heard as a marker of increased blood flow, or increased intra-cardiac pressure. Heart murmurs may indicate the presence of valvular heart disease, either as a cause (e.g. aortic stenosis) or as a result (e.g. mitral regurgitation) of the heart failure.

Right-sided failure

Physical examination can reveal pitting peripheral edema, ascites, and hepatomegaly. Jugular venous pressure is frequently assessed as a marker of fluid status, which can be accentuated by the hepatojugular reflux. If the right ventriclar pressure is increased, a parasternal heave may be present, signifying the compensatory increase in contraction strength.

Biventricular failure

Dullness of the lung fields to finger percussion and reduced breath sounds at the bases of the lung may suggest the development of a pleural effusion (fluid collection in between the lung and the chest wall). Though it can occur in isolated left- or right-sided heart failure, it is more common in biventricular failure because pleural veins drain both into the systemic and pulmonary venous system. When unilateral, effusions are often right-sided, presumably because of the larger surface area of the right lung.

  • Heart Failure
  • Heart Failure Terminology
  • Heart Failure Classification
  • Heart Failure Causes
  • Heart Failure Pathophysiology
  • Heart Failure Diagnosis
  • Heart Failure Management
  • Heart Failure Prognosis

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Heart Failure" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Heart Failure Causes

Chronic Heart Failure

The predominance of causes of heart failure are difficult to analyze due to challenges in diagnosis, differences in populations, and changing prevalence of causes with age.

A 19 year study of 13000 healthy adults in the United States (the National Health and Nutrition Examination Survey (NHANES I) found the following causes ranked by Population Attributable Risk score:

  1. Ischaemic Heart Disease 62%
  2. Cigarette Smoking 16%
  3. Hypertension (high blood pressure)10%
  4. Obesity 8%
  5. Diabetes 3%
  6. Valvular heart disease 2% (much higher in older populations)

An Italian registry of over 6200 patients with heart failure showed the following underlying causes:

  1. Ischaemic Heart Disease 40%
  2. Dilated Cardiomyopathy 32%
  3. Valvular Heart Disease 12%
  4. Hypertension 11%
  5. Other 5%

Rarer causes of heart failure include:

  • Viral Myocarditis (an infection of the heart muscle)
  • Infiltrations of the muscle such as amyloidosis
  • HIV cardiomyopathy (caused by Human Immunodeficiency Virus)
  • Connective Tissue Diseases such as Systemic lupus erythematosus
  • Abuse of drugs such as alcohol
  • Pharmaceutical drugs such as chemotherapeutic agents.
  • Arrhythmias

Obstructive Sleep Apnea a condition of sleep disordered breathing overlaps with obesity, hypertension and diabetes and is regarded as an independent cause of heart failure.

Acute decompensated heart failure

Chronic stable heart failure may easily decompensate. This most commonly results from an intercurrent illness (such as pneumonia), myocardial infarction (a heart attack), arrhythmias, uncontrolled hypertension, or a patient's failure to maintain a fluid restriction, diet or medication. Other well recognised precipitating factors include anaemia and hyperthyroidism which place additional strain on the heart muscle. Excessive fluid or salt intake, and medication that causes fluid retention such as NSAIDs and thiazolidinediones, may also precipitate decompensation.

  • Heart Failure
  • Heart Failure Terminology
  • Heart Failure Classification
  • Heart Failure Symptoms
  • Heart Failure Pathophysiology
  • Heart Failure Diagnosis
  • Heart Failure Management
  • Heart Failure Prognosis

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Heart Failure" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.