Tests that may be used to diagnose a bundle branch block or the underlying problem causing it include:

  • Electrocardiogram. An electrocardiogram records the electrical impulses in your heart through wires attached to the skin on your chest and other locations on your body. Abnormalities may indicate the presence of bundle branch block, as well as which side is being affected.
  • Echocardiogram. An echocardiogram can be used to pinpoint an underlying condition that caused the bundle branch block. This test uses sound waves to produce images of the heart, allowing your doctor to see your heart in motion.

    An echocardiogram provides detailed images of the heart's structure and shows the thickness of your heart muscle and whether your heart valves are moving normally.


Most people with bundle branch block are symptom-free and don't need treatment.

However, if you have an underlying heart condition causing bundle branch block, treatment of the underlying condition is recommended. Treatment of underlying conditions may involve using medications to reduce high blood pressure or lessen the effects of heart failure, or the use of a coronary angioplasty to open up the artery leading to your heart.

Additionally, depending on your symptoms and whether you have other heart problems, your doctor might also recommend:

  • A pacemaker. For some people with bundle branch block and a history of fainting, doctors may recommend implanting a pacemaker. A pacemaker is a compact device implanted under the skin of your upper chest (internal pacemaker) with two wires that connect to the right side of your heart. The pacemaker provides electrical impulses when needed to keep your heart beating regularly.
  • Cardiac resynchronization. Also known as biventricular pacing, this procedure is similar to having a pacemaker implanted. However, in cardiac resynchronization, there's a third wire that's connected to the left side of the heart so the device can keep both sides in proper rhythm.

Preparing for your appointment

You're likely to start by first seeing your primary care doctor. However, you may then be referred to a doctor who specializes in heart disorders (cardiologist).

Here's some information to help you get ready for your appointment, and what to expect from your doctor.

What you can do

  • Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your caffeine intake before having heart function tests.
  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including any major stresses or recent life changes.
  • Make a list of all medications, vitamins and supplements that you're taking. Also, write down the dose that you're taking.
  • Ask a family member or friend to come with you, if possible. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
  • Write down questions to ask your doctor.

Preparing a list of questions can help you make the most of your time with your doctor. For bundle branch block, some basic questions to ask your doctor include:

  • What are the most likely causes of my symptoms?
  • What kinds of tests do I need? Do these tests require any special preparation?
  • What treatments are available, and which do you recommend?
  • Will the bundle branch block return after treatment?
  • What types of side effects can I expect from treatment?
  • I have other health conditions. How can I best manage these conditions together?
  • Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:

  • When did you first begin experiencing symptoms?
  • 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?
April 10, 2015
  1. Conduction disorders. American Heart Association. http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Conduction-Disorders_UCM_302046_Article.jsp. Accessed Feb. 22, 2015.
  2. Sauer WH. Left bundle branch block. http://www.uptodate.com/home. Accessed Feb. 22, 2015.
  3. Sauer WH. Right bundle branch block. http://www.uptodate.com/home. Accessed Feb. 22, 2015.
  4. Longo DL, et al. Electrocardiography. In: Harrison's Principles of Internal Medicine. 18th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://accessmedicine.com. Accessed Feb. 22, 2015.
  5. Bussink BE, et al. Right bundle branch block: Prevalence, risk factors, and outcome in the general population: Results from the Copenhagen City Heart Study. European Heart Journal. 2013;34:138.
  6. Cardiac resynchronization therapy. American Heart Association. http://www.heart.org/HEARTORG/Conditions/HeartFailure/Cardiac-Resynchronization-Therapy_UCM_452920_Article.jsp. Accessed Feb. 22, 2015.
  7. Mankad R (expert opinion). Mayo Clinic, Rochester, Minn. March 24, 2015.