If you have a right bundle branch block and you're otherwise healthy, you might not need a full evaluation. If you have a left bundle branch block, you will need a full evaluation.

Tests that can be used to diagnose a bundle branch block or its causes include:

  • Electrocardiogram (ECG or EKG). An ECG records the electrical impulses in your heart using wires attached to the skin on your chest and sometimes your limbs. This test can show signs of a bundle branch block, as well as which side is being affected.
  • Echocardiogram. This test uses sound waves to provide detailed images of the heart's structure and the thickness of your heart muscle. It can show whether your heart valves are moving normally. Your doctor can use this test to pinpoint a condition that caused the bundle branch block.


Most people with bundle branch block don't have symptoms and don't need treatment. For example, left bundle branch block is not treated with medications. However, treatment depends on your specific symptoms and other heart conditions.


If you have a heart condition causing bundle branch block, treatment might involve medications to reduce high blood pressure or reduce symptoms of heart failure.

Surgeries and other procedures

If you have bundle branch block and a history of fainting, your doctor might recommend a pacemaker. A pacemaker is a compact device implanted under the skin of your upper chest with two wires that connect to the right side of your heart. The pacemaker releases electrical impulses when needed to keep your heart beating regularly

If you have bundle branch block with low heart-pumping function, you may need cardiac resynchronization therapy (biventricular pacing). This treatment is similar to having a pacemaker implanted. But you'll have a third wire connected to the left side of your heart so the device can keep both sides in proper rhythm. Cardiac resynchronization therapy is meant to improve the coordination of both lower chambers of the heart so that they contract at the same time.

More Information

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Preparing for your appointment

You're likely to start by seeing your primary care doctor. You might be referred to a doctor trained in heart disorders (cardiologist).

Here's some information to help you get ready for your appointment.

What you can do

Be aware of pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your caffeine intake before having heart function tests.

Make a list of:

  • Your symptoms, including any that seem unrelated to the reason for which you scheduled the appointment, when they began and how often they occur
  • Key personal information, including major stresses or recent life changes
  • All medications, vitamins and supplements you take, including the doses
  • Questions to ask your doctor

Ask a family member or friend to come with you, if possible, to help you remember the information you receive.

For bundle branch block, questions to ask your doctor include:

  • What are the most likely causes of my symptoms?
  • What tests do I need?
  • What treatments are available, and which do you recommend?
  • Will the bundle branch block return after treatment?
  • What side effects might I expect from treatment?
  • I have other health conditions. How can I best manage them together?
  • Do you have brochures or other printed material I can have? What websites do you recommend?

What to expect from your doctor

Your doctor is likely to ask you questions, including:

  • Does anything seem to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?
  • Has a doctor ever told you that you have a bundle branch block?
Nov. 20, 2021
  1. Conduction disorders. American Heart Association. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/conduction-disorders#. Accessed April 20, 2020.
  2. Sauer WH. Left bundle branch block. https://www.uptodate.com/contents/search. Accessed April 20, 2020.
  3. Sauer WH. Right bundle branch block. https://www.uptodate.com/contents/search. Accessed April 20, 2020.
  4. Bundle branch block and fascicular block. Merck Manual Professional Version. https://www.merckmanuals.com/professional/cardiovascular-disorders/arrhythmias-and-conduction-disorders/bundle-branch-block-and-fascicular-block. Accessed April 20, 2020.
  5. Cardiac resynchronization therapy. American Heart Association. https://www.heart.org/en/health-topics/heart-failure/treatment-options-for-heart-failure/cardiac-resynchronization-therapy-crt. Accessed April 20, 2020.
  6. Lopez-Jimenez F (expert opinion). Mayo Clinic March 4, 2018.
  7. Noseworthy PA (expert opinion). Mayo Clinic. Sept. 28, 2020.