Left bundle branch block

Definition

Disorder of the atrioventricular conduction system in which the QRS duration is greater than or equal to 120 ms in adults, greater than 100 ms in children 4 to 16 years of age, and greater than 90 ms in children less than 4 years of age; there is a QS or rS pattern in lead V1 and a wide slurred R wave in leads I and V6.

3 subordinate codes

• BC63.40Left anterior fascicular block
• BC63.41Left posterior fascicular block
• 4B4ZDiseases of the immune system, unspecified

Nearby in Conduction disorders

• BC63.0Atrioventricular block, first degree
• BC63.1Atrioventricular block, second degree
• BC63.2Complete atrioventricular block
• BC63.3Right bundle branch block
• BC63.5Nonspecific intraventricular conduction delay
• 4B4YOther specified diseases of the immune system
• 4B4ZDiseases of the immune system, unspecified