What is Left Bundle Branch Block (LBBB)

Left bundle branch block is a problem with the way that electrical impulses pass through the heart (electrical conduction abnormality). The heart depends on an electrical pulse to beat normally.

The electrical signal for a heartbeat starts in the upper chambers of the heart (atria) and then travels to the two lower chambers (left and rightventricles). An LBBB is a partial or complete block of the pathway that carries the signal to the left ventricle. If you have LBBB, the left side of your heart does not beat normally.

LBBB may be a warning sign of heart disease.

What are the causes?

This condition may be caused by:

• Heart disease.
• Disease of the arteries in the heart (arteriosclerosis).
• Stiffening or weakening of heart muscle (cardiomyopathy).
• Infection of heart muscle (myocarditis).
• High blood pressure (hypertension).

In some cases, the cause may not be known.

What increases the risk?

The following factors may make you more likely to develop this condition:

• Being male.
• Being 50 years of age or older.
• Having heart disease.
• Having had a heart attack or heart surgery.

What are the signs or symptoms?

This condition may not cause any symptoms. If you do have symptoms, they may include:

• Feeling dizzy or light-headed.
• Fainting.

How is this diagnosed?

This condition may be diagnosed based on an electrocardiogram (ECG). It is often diagnosed when an ECG is done as part of a routine physical or to help find the cause of fainting spells.

You may also have imaging tests to find out more about your condition. These may include:

• Chest X-rays.
• Echo test (echocardiogram).

How is this treated?

If you do not have symptoms or any other type of heart disease, you may not need treatment for this condition. However, you may need to see your health care provider more often because LBBB can be a warning sign of future heart problems. You may get treatment for other heart problems or high blood pressure.

If LBBB causes symptoms or other heart problems, you may need to have an electrical device (pacemaker) implanted under the skin of your chest. A pacemaker sends electrical signals to your heart to keep it beating normally.

Follow these instructions at home:

• Follow instructions from your health care provider about eating or drinking restrictions.
• Take over-the-counter and prescription medicines only as told by your health care provider.
• Return to your normal activities as told by your health care provider. Ask your health care provider what activities are safe for you.
• Follow a heart-healthy diet and maintain a healthy weight. Work with a diet and nutrition specialist (dietitian) to create an eating plan that is best for you.
• Get regular exercise as told by your health care provider.
• Do not use any products that contain nicotine or tobacco, such as cigarettes and e-cigarettes. If you need help quitting, ask your health care provider.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• You are light-headed or you faint.

Get help right away if:

• You have chest pain.
• You have difficulty breathing.

These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.). Do not drive yourself to the hospital.

Summary

• For the heart to beat normally, an electrical signal must travel to the lower left chamber of the heart (left ventricle). Left bundle branch block (LBBB) is a partial or complete block of the pathway that carries that signal.
• This condition may not cause any symptoms. In some cases, a person may feel dizzy or light-headed or may faint.
• Treatment may not be needed for LBBB if you do not have symptoms or any other type of heart disease.
• You may need to see your health care provider more often because LBBB can be a warning sign of future heart problems.