Bifascicular block

This code represents a conduction abnormality in the heart where two of the three main fascicles of the His-Purkinje system are blocked. This typically involves a combination of right bundle branch block (RBBB) and either left anterior fascicular block (LAFB) or left posterior fascicular block (LPFB). It indicates a defect in the electrical pathway responsible for coordinating ventricular contraction.

Assign this code when documentation explicitly states "bifascicular block" or describes the presence of RBBB with either LAFB or LPFB. This diagnosis is typically made based on electrocardiogram (ECG) findings. Ensure the physician's interpretation of the ECG clearly supports this specific conduction defect.

• Do not code individual fascicular blocks separately if a bifascicular block is diagnosed; the bifascicular code is more specific.
• Distinguish from trifascicular block (I45.3), which involves all three fascicles.
• Review the ECG interpretation carefully to confirm the specific fascicles involved.