High-Output Heart Failure

Topic Overview

High-output heart failure happens when the body's need for blood is unusually high, so heart failure symptoms happen even though the heart is working well.

This type of heart failure happens to a very small number of people with heart failure.

What happens to the heart?

High-output heart failure occurs when the normally functioning heart cannot keep up with an unusually high demand for blood to one or more organs in the body. The heart may be working well otherwise, but it cannot pump out enough blood to keep up with this extra need.

What causes it?

There are a variety of conditions that can significantly increase the body's need for blood and oxygen, resulting in high-output heart failure. These conditions include anemia, hyperthyroidism, and pregnancy. Although the causes of high-output heart failure are different from the cause of other types of heart failure, the end result is the same: Your heart isn't supplying enough blood to meet your body's needs. High-output heart failure results in the same symptoms of heart failure, including fatigue and shortness of breath.

Causes of high-output heart failure

Cause	What is it?	How does it cause high-output heart failure?
Severe anemia	Blood contains too few oxygen-carrying red blood cells.	Requires the heart to pump more blood each minute to deliver enough oxygen to the tissues of the body
Hyperthyroidism	Thyroid gland produces too much thyroid hormone.	Increases the body's overall metabolism, thus increasing the demand for blood flow
Arteriovenous fistula	An abnormal connection between an artery and a vein	Short-circuits the circulation and forces the heart to pump more blood overall to deliver the usual amount of blood to the vital organs
Beriberi	Deficiency of thiamine (vitamin B1)	Leads to increased metabolic demand and increased need for blood flow
Paget's disease	Abnormal breakdown and regrowth of bones, which develop an excessive amount of blood vessels	Increased number of blood vessels requires increased cardiac output.