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.

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