Acute heart failure refers to the heart being unable to pump enough blood around the body. It occurs suddenly and can be life threatening.

If a person has heart failure, their heart cannot work effectively to supply blood to the body. This may be because it cannot relax as usual. Heart failure can cause fluid to build up in the lungs.

A person may notice breathlessness, changes in their heart’s rhythm, and fluid retention, which can lead to swelling in their legs and elsewhere.

The symptoms of acute heart failure either appear suddenly or worsen quickly. The underlying cause may be damage or stiffness in the heart, and the stiffness may have developed over a long period.

Anyone with symptoms of heart failure needs immediate medical attention. The doctor may recommend taking medication, making certain lifestyle changes, or having surgery.

This article explores acute heart failure in detail, including its causes, symptoms, and more.

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Heart failure means that the heart is unable to serve the body’s needs because it cannot pump enough blood or relax sufficiently.

Acute heart failure can result from an event such as a viral infection or blockage affecting an artery around the heart. Doctors may call this “de novo” acute heart failure.

It may instead result from damage in the heart, which may have developed over time. Doctors may call this “acute on chronic” heart failure.

Heart failure can affect one or both sides of the heart. However, it usually starts on the left side.

Left sided heart failure can be diastolic or systolic. Systolic heart failure affects the left ventricle and the way it pumps out blood. Diastolic heart failure happens when the left ventricle does not relax properly.

Right sided heart failure can happen alone, but it often occurs with left sided heart failure, when the left chamber puts pressure on the right side.

Congestive heart failure develops when blood flow from the heart becomes slower, causing a backup of blood returning to the heart. Fluid collects in the legs, abdomen, lungs, and other parts of the body. If it collects in the lungs, the medical name for this is pulmonary edema.

This type of heart failure can also be diastolic or systolic.

Acute heart failure can cause a buildup of fluid in the lungs and cardiogenic shock, which refers to the heart being unable to pump enough blood to the brain and other key organs. These can lead to:

  • confusion
  • rapid breathing
  • a loss of consciousness
  • multiorgan failure

People with acute heart failure may also have:

  • breathlessness, especially when walking
  • swelling in the lower limbs or abdomen
  • shortness of breath when lying down
  • a need for extra pillows
  • weight gain
  • low blood pressure
  • progressive fatigue
  • a cough

Many people with acute heart failure need emergency medical treatment and spend time in the hospital.

The treatment options depend on the cause and how the condition progresses. A doctor may recommend:

Oxygen therapy

This is important if levels of oxygen in the blood are low. Supplemental oxygen may be delivered through a mask or a tube attached to mechanical breathing equipment.


A doctor may prescribe:

  • diuretics, to remove excess fluid
  • vasodilators, to dilate blood vessels
  • inotropes, which help the heart squeeze harder to get the fluid out of the lungs
  • antibiotics, if there is a bacterial infection
  • treatments for an irregular heartbeat

Surgery and other approaches

Depending on the underlying cause of the condition and the specific symptoms or complications, a doctor may recommend:

  • surgery, to open blocked passages in the heart or repair heart valves, for example
  • monitoring the person’s fluid balance, kidney health, and other factors, to manage diabetes
  • assessing blood pressure, heart rate, and other cardiac measures, to control high blood pressure
  • counseling, for alcohol or drug use
  • preparing a follow-up plan that includes sodium and fluid restriction

The heart has four chambers, which work together to pump blood around the body. Problems can arise in any part of the heart.

In cases of de novo acute heart failure, a single problem or event causes symptoms. This may be a virus, drug use, sudden damage to a heart valve, or a blockage in a coronary artery.

In cases of acute on chronic heart failure, the heart tries to compensate for a loss of squeezing or relaxing function that has developed over time.

Here are some of the ways that the heart tries to compensate:

  • It stretches so that it can contract more, eventually becoming enlarged.
  • It develops increased muscle mass, which can stiffen the heart muscle.
  • It beats faster as it tries to supply more blood.
  • Blood vessels narrow to maintain blood pressure.
  • The body diverts blood away from other organs toward the heart.

In time, these changes can affect the health of the heart and other organs, such as the kidneys. A problem with the kidneys can also worsen fluid retention from heart failure, as the body is unable to get rid of salt and water effectively.

Risk factors and comorbidities

Someone with acute heart failure may also have:

In some cases, there is overuse of alcohol or recreational drugs.

Some factors that can trigger acute heart failure include:

  • acute coronary syndrome, which involves a sudden reduction of blood flow to the heart
  • a stroke
  • a previous heart attack
  • the use of some drugs or a combination of medications
  • infections
  • discontinuing treatment for a heart condition
  • an irregular heartbeat
  • high blood pressure
  • valvular heart disease

Studies suggest that 20–30% of people with acute heart failure also have kidney problems, and 40% have diabetes.

People with underlying heart problems may also be more prone to lung infections and cellulitis. The heart’s inability to supply blood effectively can make it hard for the body to stay healthy overall.

To make a diagnosis, a doctor performs a physical examination and looks at the person’s medical history.

Using a stethoscope, the doctor listens to the person’s heart to check for unusual rhythms or extra sounds. They also listen to the lungs to check for congestion.

The doctor may also check for swelling in the person’s abdomen, legs, and veins in the neck.

They may then recommend tests, such as:

  • blood tests
  • an echocardiogram
  • imaging tests, such as a chest X-ray
  • an angiogram, if there are signs of a heart blockage
  • a chest CT scan, if there are signs of a pulmonary embolism or blood clot

As part of a person’s rehabilitation plan, the doctor may recommend:

  • losing weight, if appropriate
  • having a healthy diet that is low in salt, fat, and sugar and high in fresh fruits and vegetables
  • getting regular exercise
  • managing stress through exercise, meditation, and rest
  • avoiding smoke or quitting smoking, if necessary
  • attending regular follow-up visits and taking medications
  • limiting the intake of sodium to fewer than 1,500 milligrams per day
  • limiting the intake of fluid to under 2 liters per day

Be sure to check with a doctor before making these or any other lifestyle changes.

Learn more about a heart-healthy diet here.

Acute heart failure does not mean that the heart has stopped working altogether, but it can be life threatening without prompt medical attention.

Receiving medical care in the first hour can prevent severe complications, and having treatment before reaching the hospital can be lifesaving and minimize the hospital stay. For this reason, people need help as soon as the symptoms appear.

The outlook for people with acute heart failure depends on factors such as their overall health, the cause of the problem, how severe it is, and how quickly they receive treatment.

Many people have full, healthy lives after experiencing heart failure, but it is essential to follow medical guidance carefully to prevent future problems.

Symptoms of acute heart failure appear or worsen suddenly. They may stem from an event such as an infection, but heart failure often results from a longer-term problem.

A person may experience confusion, congestion, fluid retention, breathlessness, and changes in their heart rhythm.

Anyone who may be experiencing acute heart failure needs immediate medical attention. Receiving treatment right away can be lifesaving and prevent complications.

Read this article in Spanish.