Right bundle branch block (RBBB) is a slowing of electrical impulses to the heart’s right ventricle. This is the lower-right part of the heart.

In order for your heart to beat properly, electrical impulses are sent through a pathway, including two areas on either ventricle called the right and left bundles.

If either of these bundles becomes damaged due to issues like a heart attack or high blood pressure, the electric impulse can move more slowly. This makes it harder for the heart to pump blood throughout your body and may cause your heart to beat abnormally.

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Medical Illustration by Bailey Mariner

RBBB doesn’t always cause symptoms. In fact, some people have it for years and don’t realize it until it shows up on an electrocardiogram (ECG or EKG).

But in rare cases, a delay in the arrival of electrical impulses to the heart’s right ventricle can cause syncope. Syncope is fainting due to unusual heart rhythms that affect blood pressure.

Some people might also experience something called presyncope. This involves feeling like you’re about to faint but never actually fainting.

RBBB doesn’t always require treatment, especially if you don’t have any underlying heart conditions. If you do have another heart condition, your doctor might suggest treating the underlying cause.

If you have RBBB due to a heart attack with other electrical system conditions, for example, you may need a pacemaker. This is a device that emits electricity to help your heart maintain a consistent rhythm.

If you have high blood pressure, you may need to take medication to help manage it. This will also reduce the strain on your heart.

While treating the underlying condition might not completely get rid of RBBB, it can prevent future damage.

The right side of the heart is responsible for pumping blood to the lungs to be oxygenated. The oxygenated blood returns to the left side of the heart, where it’s pumped to the rest of the body.

This is why RBBB is sometimes related to lung problems, like:

Other potential causes of RBBB include:

Also, as you age, your heart tissue can gradually change. Sometimes, this results in RBBB.

While anyone can develop RBBB, some people have a higher risk due to other conditions that affect their heart or lungs.

Conditions that can increase your risk of bundle branch block on either the left or right side include:

If you have any of these conditions, your doctor might regularly monitor your heart rhythm to detect any signs of a bundle branch block.

Doctors usually diagnose RBBB by using an electrocardiogram. This is a painless test that involves placing stickers called leads around your chest. The leads conduct electricity. They’re connected to wires that sense the electrical impulses of your heart and trace your heart’s rhythm.

Sometimes, a bundle branch block makes it harder for doctors to diagnose other heart conditions, like heart failure or enlargement. If you’ve been diagnosed with RBBB, make sure to tell any other doctors you see that you have one.

When they’re first discovered, right bundle branch blocks can seem alarming, but they’re usually not as serious as they sound. In some cases, you might not even know you have one for many years.

If you have RBBB that needs treatment, your doctor will develop a plan that addresses the underlying cause.