Left bundle branch block is a heart condition that causes heart fragility. It does not always cause symptoms, but some people may feel lightheaded and develop chest pain.
An electrocardiogram (ECG) can record the heart’s rhythm and indicate the type of heart block a person has.
This article explains a left bundle branch block in more detail and looks at its causes, risk factors, symptoms, and more.
Bundle branch blocks occur when there is blockage or disruption in the heart’s electrical impulses. They cause those impulses to travel more slowly to the heart’s ventricles.
It can happen on the left and right side pathways of the ventricles, and doctors can see this blockage on an electrocardiogram (ECG) machine.
A left bundle branch block can indicate an underlying heart condition. It causes an abnormal heart rhythm and is common in those who have experienced heart damage.
A right bundle branch block can develop in people without any health conditions.
People with a left bundle branch block have an increased risk of heart disease compared to the general population.
According to the National Library of Medicine (NLM), cardiac resynchronization treatment (CRT), one type of heart block therapy, can reduce death by up to 37%.
Medical professionals may use the following tools to determine if a person has a left bundle branch block.
Electrocardiogram (ECG)
An ECG measures the heart’s electrical impulses at rest or during exercise and can indicate the type of heart block present.
During the test, the doctors place electrodes on the person’s chest. The ECG produces a visual image of the heart rhythm.
People may also have to wear a portable ECG monitor so doctors can check the heart’s electrical activity over time.
An ECG test is painless, but people may feel some discomfort when the doctor removes the electrodes.
Holter monitor
A Holter monitor is a wearable device that can monitor the heart’s rhythm for up to 48 hours. It can detect changes in the heart’s rhythm, even if a person does not experience them frequently.
Implantable loop recorder
An implantable loop recorder is a heart recorder that medical professionals insert beneath the skin. It can record the heart rhythm for up to 3 years.
There is currently no treatment for a left bundle branch block. Doctors usually treat any accompanying heart condition a person may have.
For example, a pacemaker may be an option for people who develop a heart block while having a heart attack. This can help regulate the heart rhythm, as a bundle branch block can cause bradycardia and the heart to become fragile.
However, if a person has alternating right and left bundle branch blocks, a doctor may also recommend a pacemaker.
The Centers for Disease Control and Prevention (CDC) recommend exercising, eating a balanced diet, and avoiding smoking to help improve heart health.
The American Heart Association also recommends the following for those who have a pacemaker:
- carrying a pacemaker ID card
- avoiding strong electrical fields
- going to regular pacemaker checkups
- keeping an eye on your heart rate
Research shows that there is no specific treatment for people with left bundle branch block. However, a person may receive treatment if they have another heart condition.
The CDC recommends people seek immediate medical help if they or someone else is experiencing heart attack symptoms. These may include:
- shortness of breath
- pain in the neck or jaw
- feeling lightheaded
- chest pain
A person should also consider seeing a doctor if they have an irregular heartbeat, high blood pressure, or a family history of heart disease.
A left bundle branch block is a heart block condition mostly affecting older adults. It may also develop in people who have had a heart attack or heart surgery.
During an ECG test, a medical professional can examine the heart rhythm and determine if a person has a left bundle branch block.
People should seek medical attention if they experience chest pain, shortness of breath, or lightheadedness.
Left bundle branch block (LBBB) is an abnormality of the electrical conducting system of the heart. There are two main conducting pathways in the heart, the left and the right bundle. In LBBB, the left conducting pathway no longer functions so electrical conduction is maintained through the right bundle. LBBB is more common in structural abnormalities of the heart such as in heart muscle conditions, high blood pressure or coronary artery narrowing.
How common is it?
LBBB affects approximately 1 in 100 of the population.
What symptoms might I get?
LBBB does not give symptoms in the absence of any other underlying heart abnormality,
What extra tests are required?
Patients with LBBB usually require a heart ultrasound, a Holter ECG monitor and a stress test such as an exercise tolerance test to try and exclude associated heart conditions.
Will I need treatment?
Usually not.
Is it hereditary?
No, but LBBB can be associated with conditions that are, such as cardiomyopathies.
Does this affect my life expectancy?
It can do. LBBB has been shown to be a marker for cardiac conditions that can increase the risk of heart failure and cardiac death. Patients with LBBB also have a higher lifetime risk of needing a pacemaker.
What happens next?
If you have been diagnosed with LBBB then a consultation can be offered to you with a local cardiologist to discuss any further tests or treatment.
Useful links
//en.wikipedia.org/wiki/Left_bundle_branch_block