High output heart failure is a rare form of heart failure. It can occur in people with hyperthyroidism, sepsis, or lung disease. Treatment can help stabilize symptoms and target conditions causing heart failure.

The Centers for Disease Control and Prevention (CDC) estimates that about 6.2 million adults have heart failure in the United States. It is the most common condition that doctors diagnose in hospitals.

This article describes what high output heart failure is in more detail.

Learn more about heart failure here.

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When a person has heart failure, their heart does not pump enough blood throughout their body.

In the case of high output heart failure, however, the heart pumps a regular blood supply, and sometimes even higher volumes, but is still unable to meet the body’s demands.

There are several potential causes of high output heart failure. These include:

Metabolic effects

The body’s metabolic process helps convert food into energy and eliminate waste.

According to a 2016 study, metabolic high output heart failure causes an increase in metabolic demands, adding extra pressure on the heart.

Hyperthyroidism, or overactive thyroid, is a condition that causes the overproduction of thyroid hormones. This can increase the heart’s contractility, rate, and metabolism.

One 2007 study suggests that people with untreated tachycardia, hypercontractility, or volume overload may be more likely to develop cardiomyopathy and hypertrophy.

Another health condition that doctors associate with high output cardiac failure is myeloproliferative disorders. These include:

Additionally, severe thiamine deficiency causes a serious disorder called beriberi. Beriberi can lead to symptoms of heart failure if a person does not receive treatment. Severe thiamine deficiency causes a buildup of pyruvate and lactate in the blood, which causes vasodilation and can eventually lead to cardiomyopathy.

Myocardial effects

Diseases or infections directly or indirectly affecting the heart may also cause high output heart failure.

Sepsis is an extreme bodily response to infection.

According to the CDC, sepsis can lead to:

Sepsis causes a decrease in blood volume. At later stages, it also reduces the heart’s function.

Chronic lung disease also tends to cause high output cardiac failure, especially on the right-hand side of the heart. It reduces oxygen volume, causing the heart to work harder to pump more blood.

Peripheral vascular effects

Peripheral vascular effects are changes that affect the vascular system, such as the arteries, capillaries, and veins.

For example, an arteriovenous (AV) fistula is an irregular link between a vein and an artery, which allows blood to move directly into a vein from an artery. An AV fistula may be present at birth or develop later in life. When an artery bypasses a vein, it can lead to an increased supply of blood flow to the heart.

High output cardiac failure may occur as the heart rate increases and the body has more blood volume to handle.

The term “heart failure” does not mean the heart has stopped working. It occurs when the heart cannot pump enough oxygen-rich blood to the body.

Researchers refer to this as “low output heart failure.” There are two types of low output heart failure:

Heart failure with reduced pumping ability

In this type, the heart muscles are weak. They do not produce enough blood during contraction, so the other body organs do not get enough oxygen-rich blood to function adequately.

Heart failure with preserved pumping ability

In this type, when the heart pumps out blood, it cannot relax and widen enough to fill up with blood. As a result, the body’s organs do not get enough blood supply, especially while a person is exercising.

People with heart failure usually have an increase in systemic vascular resistance. However, people with high output heart failure have typical cardiac function and a decrease in systemic vascular resistance.

People with high output heart failure may have similar symptoms to those with low output heart failure. These include:

Symptoms may also be related to the underlying condition, such as overactive thyroid.

During diagnosis, doctors may perform a physical exam, taking note of any symptoms that might be present. They may also ask the person about medications and any other health conditions they have.

Testing that may help doctors confirm a diagnosis and determine the type of heart failure includes:

  • Echocardiogram: An echocardiogram is a type of ultrasound that uses sound waves to see the heart’s muscles.
  • Stress test: Also known as a treadmill test, a stress test monitors the heart’s activity during exercise. It also helps determine the type of exercise suitable for the body.
  • MRI: MRIs reveal the heart’s structure and indicate whether there is a lack of blood supply traveling to the heart or damage from a heart attack.
  • Chest X-ray: Medical professionals can take X-rays while people are standing or lying down. The image can indicate whether there is heart enlargement or fluid in the lungs.
  • Blood tests: Doctors may order blood tests to measure certain blood substance levels. Abnormal results may indicate the person has heart failure. The tests may measure:

Treatment depends on the severity of heart failure, but the aim is to stabilize the body.

Diuretics and oxygen supplementation may be beneficial for people with high output heart failure.

Diuretics are medications that help the body eliminate extra fluid and salt. Doctors may also prescribe them to treat high blood pressure.

Inotropic medications may also be helpful if people have low blood pressure.

Doctors will also attempt to treat the underlying cause of heart failure. Here are some examples:

  • Hyperthyroidism: The most common drugs healthcare professionals prescribe to treat an overactive thyroid are carbimazole and propylthiouracil. A person may take these with a beta-blocker to relieve symptoms. Other forms of hyperthyroidism treatment may also include radiotherapy or surgery.
  • Sepsis: Doctors treat sepsis with antibiotics and intravenous fluids.
  • Cirrhosis: People with advanced cirrhosis may require liver transplantation. Medications may also be an option to manage fluid buildup from hypervolemia.

The National Heart, Lung, and Blood Institute also highlights the importance of lifestyle strategies to help support heart health. The organization recommends:

  • exercising regularly
  • quitting smoking, if applicable
  • managing stressful situations
  • managing certain factors that could lead to heart failure, such as:
    • anemia
    • blood pressure
    • irregular heart rhythm

While there is no cure for heart failure, treatment can help improve a person’s quality of life.

Authors of a 2016 study associate high output heart failure with a high risk of death. They note high output heart failure is more likely to develop in people with liver and kidney diseases.

Low vascular resistance or blood pressure can lead to poor outcomes.

High output heart failure occurs when the heart pumps blood normally or excessively, but the body is still not getting the blood it needs to function.

There is no cure for heart failure, but it is treatable.

Treatment may include medications, surgery, or intravenous fluids, depending on the cause of the disease and its severity.

Different tests can help medical professionals examine heart rhythm and function, including echocardiograms and stress tests.