LBBB ICD-10-CM Codes | 2023

Explore ICD-10-CM codes for Left Bundle Branch Block (LBBB) in 2023. Learn about common codes, billable statuses, and gain clinical insights in this comprehensive guide.

By Patricia Buenaventura on Aug 8, 2025.

Fact Checked by Ericka Pingol.

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What ICD-10 Codes are Used for Left Bundle Branch Block (LBBB)

Left Bundle Branch Block (LBBB) is a cardiac conduction abnormality that affects the heart's electrical system. Here are commonly used ICD-10-CM codes for LBBB, along with brief clinical descriptions:

I45.2 - Left anterior fascicular block: Used for LBBB that affects the left anterior fascicle, a subdivision of the left bundle branch.
I45.3 - Left posterior fascicular block: Applied when LBBB specifically involves the left posterior fascicle, another subdivision of the left bundle branch.
I45.4 - Other and unspecified fascicular block: Utilized for LBBB cases that affect other or unspecified fascicles of the left bundle branch.
I49.4 - Bundle-branch reentry ventricular tachycardia: This code may be used for LBBB when it leads to bundle-branch reentry ventricular tachycardia, a specific heart rhythm abnormality.

Which LBBB ICD Codes are Billable

The billable status of the mentioned ICD-10 codes for LBBB varies:

I45.2 - Left anterior fascicular block: Yes, billable. Medical expenses for LBBB involving the left anterior fascicle can be claimed.
I45.3 - Left posterior fascicular block: Yes, billable. Costs associated with LBBB affecting the left posterior fascicle can be reimbursed.
I45.4 - Other and unspecified fascicular block: Yes, billable. Medical expenses for other or unspecified fascicular block-related LBBB can be claimed.
I49.4 - Bundle-branch reentry ventricular tachycardia: Yes, billable. Costs associated with LBBB leading to bundle-branch reentry ventricular tachycardia can be reimbursed.

Clinical Information

Left Bundle Branch Block (LBBB) is an abnormal pattern seen on an electrocardiogram (ECG) that indicates a delay or blockage in the electrical conduction of the heart's left bundle branch.
It can be caused by various heart conditions, such as heart disease, high blood pressure, or cardiomyopathy, or it can be benign.
Diagnosis is made through an ECG, which shows characteristic changes in the QRS complex, specifically a widened QRS complex and changes in the direction of electrical depolarization in the heart.
LBBB can affect the heart's ability to pump blood effectively, potentially leading to symptoms like palpitations or shortness of breath.
Treatment depends on the underlying cause. Identifying and managing any heart conditions is crucial.
If LBBB is causing severe symptoms or heart failure, a pacemaker may be considered to restore normal heart rhythm.
Patient education should include understanding the potential causes and the need for ongoing monitoring and management of LBBB.
Healthcare practitioners play a key role in diagnosing the condition, determining its underlying cause, and providing appropriate treatm

Synonyms Include

ICD-10 LBBB
Left Bundle Branch Block
Heart Conduction Abnormality
I45.2
I45.3
Bundle-Branch Reentry Ventricular Tachycardia

Commonly asked questions

LBBB may not be serious, but it is often associated with underlying heart conditions. The significance of LBBB depends on the individual's overall heart health and other heart problems.

LBBB can result from various factors, including heart disease, heart attacks, cardiomyopathy, and certain medications. It may also occur in isolation without an underlying heart condition.

LBBB is typically diagnosed through an electrocardiogram (ECG or EKG), a non-invasive test that records the heart's electrical activity. If LBBB is detected, further evaluation may be needed to determine the underlying cause.

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