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What Causes Heart Failure?

Conditions that damage or overwork the heart muscle can cause heart failure. Over time, the heart weakens. It isn't able to fill with and/or pump blood as well as it should.

As the heart weakens, certain proteins and substances might be released into the blood. These substances have a toxic effect on the heart and blood flow, and they worsen heart failure.

Common Causes of Heart Failure

The most common causes of heart failure are coronary heart disease (CHD), high blood pressure, and diabetes. Treating these problems can prevent or improve heart failure.

Coronary Heart Disease

CHD is a condition in which a waxy substance called plaque (plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart muscle.

Plaque narrows the arteries and reduces blood flow to your heart muscle. The buildup of plaque also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow.

CHD can lead to chest pain or discomfort called angina (an-JI-nuh or AN-juh-nuh), a heart attack, heart damage, or even death.

High Blood Pressure

Blood pressure is the force of blood pushing against the walls of the arteries. If this pressure rises and stays high over time, it can weaken your heart and lead to plaque buildup.

Blood pressure is considered high if it stays at or above 140/90 mmHg over time. (The mmHg is millimeters of mercury—the units used to measure blood pressure.) If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher.


Diabetes is a disease in which the body's blood glucose (sugar) level is too high. The body normally breaks down food into glucose and then carries it to cells throughout the body. The cells use a hormone called insulin to turn the glucose into energy.

In diabetes, the body doesn't make enough insulin or doesn't use its insulin properly. Over time, high blood sugar levels can damage and weaken the heart muscle and the blood vessels around the heart, leading to heart failure.

Other Causes

Other diseases and conditions also can lead to heart failure, such as:

  • Cardiomyopathy (KAR-de-o-mi-OP-ah-thee), or heart muscle disease. Cardiomyopathy may be present at birth or caused by injury or infection.
  • Heart valve disease. Problems with the heart valves may be present at birth or caused by infection, heart attack, or damage from heart disease.
  • Arrhythmias (ah-RITH-me-ahs), or irregular heartbeats. These heart problems may be present at birth or caused by heart disease or heart defects.
  • Congenital (kon-JEN-ih-tal) heart defects. These problems with the heart's structure are present at birth.

Other factors also can injure the heart muscle and lead to heart failure. Examples include:

  • Treatments for cancer, such as radiation and chemotherapy
  • Thyroid disorders (having either too much or too little thyroid hormone in the body)
  • Alcohol abuse or cocaine and other illegal drug use
  • Too much vitamin E

Heart damage from obstructive sleep apnea may worsen heart failure. Sleep apnea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep.

Sleep apnea can deprive your heart of oxygen and increase its workload. Treating this sleep disorder might improve heart failure.

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Last Updated: March 27, 2014