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Heart failure

Heart failure is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Heart failure rather than just read about it. In short: Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically presents with shortness of breath, excessive fatigue, and bilateral leg swelling.

Heart failure — main illustration
Heart failure — illustration

Key takeaways

  • Heart failure belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Heart failure to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Heart failure from memory before moving on to harder problems.

Reference excerpt

Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically presents with shortness of breath, excessive fatigue, and bilateral leg swelling. The severity of the heart failure is mainly decided based on ejection fraction and also measured by the severity of symptoms. Other conditions that have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease. Common causes of heart failure include coronary artery disease, heart attack, high blood pressure, atrial fibrillation, valvular heart disease, excessive alcohol consumption, infection, and cardiomyopathy. These cause heart failure by altering the structure or the function of the heart or in some cases both. There are different types of heart failure: right-sided heart failure, which affects the right heart, left-sided heart failure, which affects the left heart, and biventricular heart failure, which affects both sides of the heart. Left-sided heart failure may be present with a reduced ejection fraction or with a preserved ejection fraction. Heart failure is not the same as cardiac arrest, in which blood flow stops completely due to the failure of the heart to pump. Diagnosis is based on symptoms, physical findings, and echocardiography. Blood tests, and a chest X-ray may be useful to determine the underlying cause. Treatment depends on severity and case. For people with chronic, stable, or mild heart failure, treatment usually consists of lifestyle changes, such as not smoking, physical exercise, and dietary changes, as well as medications. In heart failure due to left ventricular dysfunction, angiotensin-converting-enzyme inhibitors, angiotensin II receptor blockers (ARBs), or angiotensin receptor-neprilysin inhibitors, along with beta blockers, mineralocorticoid receptor antagonists and SGLT2 inhibitors are recommended. Diuretics may also be prescribed to prevent fluid retention and the resulting shortness of breath. Depending on the case, an implanted device such as a pacemaker or implantable cardiac defibrillator may sometimes be recommended. In some moderate or more severe cases, cardiac resynchronization therapy (CRT) or cardiac contractility modulation may be beneficial. In severe disease that persists despite all other measures, a cardiac assist device ventricular assist device, or, occasionally, heart transplantation may be recommended. Heart failure is a common, costly, and potentially fatal condition, and is the leading cause of hospitalization and readmission in older adults. Heart failure often leads to more drastic health impairments than the failure of other, similarly complex organs such as the kidneys or liver. In 2015, it affected about 40 million people worldwide. Overall, heart failure affects about 2% of adults, and more than 10% of those over the age of 70. Rates are predicted to increase. The risk of death in the first year after diagnosis is about 35%, while the risk of death in the second year is less than 10% in those still alive. The risk of death is comparable to that of some cancers. In the United Kingdom, the disease is the reason for 5% of emergency hospital admissions. Heart failure has been known since ancient times in Egypt; it is mentioned in the Ebers Papyrus around 1550 BCE.

Definition The term "cardiovascular insufficiency" is sometimes used when the heart does not function effectively as a pump and fails to circulate enough blood through the circulatory system to meet the body's needs. This generally leads to the syndrome of heart failure, a combination of signs and symptoms when the heart functions poorly as a pump. This leads to high filling pressure in the left atrium with fluid accumulation and water retention. Most of the visible signs of heart failure are the result of this fluid accumulation (edema) and the adjective congestion is added to the definition of heart failure. Impaired ejection can lead to inadequate blood flow to the body tissues, resulting in ischemia.

Signs and symptoms

Congestive heart failure is a pathophysiological condition in which the heart's output is insufficient to meet the needs of the body and lungs. The term "congestive heart failure" is often used because one of the most common symptoms is congestion or fluid accumulation in the tissues and veins of the lungs or other parts of a person's body. Congestion manifests itself particularly in the form of fluid accumulation and swelling (edema), in the form of peripheral edema (causing swollen limbs and feet) and pulmonary edema (causing difficulty breathing) and ascites (swollen abdomen). Pulse pressure, which is the difference between the systolic ("top number") and diastolic ("bottom number") blood pressures, is often low/narrow (i.e. 25% or less of the level of the systolic) in people with heart failure, and this can be an early warning sign. Symptoms of heart failure are traditionally divided into left-sided and right-sided because the left and right ventricles supply different parts of the circulation. In biventricular heart failure, both sides of the heart are affected. Left-sided heart failure is the more common.

… excerpt ends here. Continue reading the full article.

Illustrations

Heart failure illustration
Heart failure: Signs and symptoms of severe heart failure
Signs and symptoms of severe heart failure
Heart failure: Severe peripheral pitting edema
Severe peripheral pitting edema
Heart failure: Kerley B lines in radiograph of acute cardiac decompensation. The short, horizontal lines can be found everywhere in the right lung.
Kerley B lines in radiograph of acute cardiac decompensation. The short, horizontal lines can be found everywhere in the right lung.
Heart failure: Model of a normal heart (left); and a weakened heart, with over-stretched muscle and dilation of left ventricle (right); both during diastole
Model of a normal heart (left); and a weakened heart, with over-stretched muscle and dilation of left ventricle (right); both during diastole

Worked examples

Example 1 — a first encounter with Heart failure

Start with the simplest possible case. Write down what Heart failure claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Heart failure before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Heart failure ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Heart failure

In research
Heart failure appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Heart failure in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Heart failure is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aging-associated diseases, Disorders causing edema, Heart diseases, so understanding it makes those chapters shorter.
In everyday life
Look for Heart failure outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Heart failure in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Heart failure means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Heart failure out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Heart failure in simple terms?

Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically presents with shortness of breath, excessive fatigue, and bil…

Why does Heart failure matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Heart failure?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Heart failure.

Tags

  • Aging-associated diseases
  • Disorders causing edema
  • Heart diseases
  • Organ failure

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