High-output heart failure is a rare form of heart failure that’s very different from other types. With most types of heart failure, the heart doesn’t pump enough blood to the body. With high-output heart failure, your heart pumps a normal amount of blood, but your tissues and organs don’t get enough blood to meet their needs.

What Is High-Output Heart Failure?

Most people living with heart failure will have low cardiac output — the amount of blood the heart pumps in one minute. When your cardiac output is low, not enough blood flows to your tissues and organs.

High cardiac output, on the other hand, may lead to high-output heart failure. If you have this type of heart failure, your heart pumps enough blood, but either your body needs more blood than normal to function or your blood vessels are too relaxed.

Why do blood vessels relax too much in people with high-output heart failure? In low-output heart failure, the heart muscles don’t contract as strongly when the heart beats. This is measured by ejection fraction — the percentage of blood that leaves your heart when it contracts. To make up for a lower amount, the blood vessels of people with low-output heart failure constrict or get narrower.

However, in high-output heart failure, the ejection fraction is normal: The heart pumps enough blood, but blood vessels open up more (called vasodilation) because the body needs more blood. With widened blood vessels, however, less blood flows to some organs, such as the kidneys, which attempt to retain more salt and water to increase blood volume. This can lead to an overload of fluid.

High-output heart failure is usually caused by another condition, such as:

• High body weight
• Liver disease
• Hyperthyroidism (high thyroid hormone)
• Sepsis (the body’s extreme response to infection)
• Anemia (low red blood cells)
• Abnormal blood flow connections between arteries and veins

High-output heart failure causes your heart to work harder to meet your body’s need for blood. Even though your heart is doing its job, this type of heart failure causes symptoms similar to those of other types. High-output heart failure is a serious condition that requires medical attention.

Symptoms

The symptoms of high-output heart failure are similar to those of low-output heart failure, even though the causes and treatments are different. You might experience symptoms such as these:

• Difficulty breathing
• Fatigue
• Swollen feet, ankles, legs, abdomen, or hands
• Confusion
• Nausea or lack of appetite
• Coughing or wheezing
• Fast or irregular heartbeat

In contrast to other types of heart failure, high-output heart failure tends to lead to warm rather than cold hands and feet because of widened blood vessels.

Diagnosis

To diagnose heart failure and determine the type, your health care provider will perform a physical examination, check your vital signs (including heart rate and blood pressure), ask you questions, and run tests. Possible tests include the following:

• Blood tests to check levels of substances such as sodium and potassium
• Electrocardiogram (ECG or EKG) to measure your heart’s electrical activity
• Echocardiogram to take an image of your heart and look at how it is working
• Stress test to measure your heart’s response to exercise
• Chest X-ray to see if you have an enlarged heart or chest congestion
• Cardiac catheterization, in which your doctor inserts a small tube into a blood vessel to look for blockages

If you are diagnosed with high-output heart failure, your doctor will perform additional tests to determine the underlying medical condition that is causing it.

Causes

High-output heart failure might occur because of diseases that change the function of your heart, blood vessels, or blood flow or cause your organs to need more blood — reasons that differ from those of other types of heart failure. Conditions such as these may lead to high-output heart failure:

• High body weight
• Pregnancy
• Liver disease
• Arteriovenous fistulas (abnormal connections between arteries and veins)
• Lung disease
• Myeloproliferative disorders (conditions related to bone marrow and blood cells)
• Septic shock (the body’s extreme response to infection)
• Anemia
• Hyperthyroidism
• Beriberi (thiamine deficiency)
• Paget’s disease (bone overgrowth)

One MyHeartDiseaseTeam member shared, “I found out I have heart failure when I was admitted to the hospital with septic shock and pneumonia.”

Treatments

The usual treatments for other kinds of heart failure — such as ACE inhibitors, angiotensin-receptor blockers, angiotensin receptor-neprilysin inhibitors, and beta-blockers — may not work as well for high-output heart failure. These treatments actually may worsen high-output heart failure.

Your medical team will first take steps to stabilize your body’s functions, such as your breathing and heart rate. If you are diagnosed with high-output heart failure, the treatment will depend on the underlying cause. For example, people with hyperthyroidism may need antithyroid drugs.

If the heart failure is severe and your medical team is still trying to find the underlying cause, you may be given medications called vasoconstrictor adrenergic drugs to help make your blood vessels get smaller. Vasoconstrictor adrenergic drugs include:

• Noradrenaline
• Ephedrine
• Phenylephrine

To get rid of excess body fluid or reduce swelling, your doctor may recommend medications such as diuretics (water pills). You might also be advised to eat less salt.

Prevention

It’s difficult to prevent high-output heart failure because it’s often caused by another health condition that you can’t predict. However, you can take steps like these to lower your risk of heart failure and other types of heart disease:

• Choose foods that are low in sodium, and try to eat a variety of fresh fruits and vegetables, whole grains, and lean protein.
• Speak with a registered dietitian if you are concerned about your diet.
• Move your body as regularly as possible. Aim for about 2 hours and 30 minutes a week of low- to moderate-intensity exercise, such as brisk walking or cycling — or whatever form of activity you enjoy.
• Quit or cut back on cigarette or tobacco use.
• Limit your alcohol intake.

One MyHeartDiseaseTeam member shared, “I have tried my best to get off the sweets, and I have cut down on salt a lot.” Another member wrote, “I had a lot of swelling in my feet, and I stopped adding salt to my food. I was shocked that this helped reduce all the swelling.”

Be sure to check in with your doctor before starting a new diet or exercise program. They can help guide you in making the most appropriate lifestyle changes to keep your heart as healthy as possible.

Talk With Others Who Understand

MyHeartDiseaseTeam is the social network for people with heart disease and their loved ones. On MyHeartDiseaseTeam, more than 55,000 members come together to ask questions, give advice, and share their stories with others who understand life with heart disease.

Are you living with high-output heart failure? Have you taken any steps to prevent heart failure? Share your experience and tips in the comments below or by posting on MyHeartDiseaseTeam.