ICD-10 Code I44.4 – Left anterior fascicular block (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I44.4 – Left anterior fascicular block
What it is
Left anterior fascicular block is a conduction delay in the left anterior fascicle of the heart’s electrical system. It changes the direction of ventricular activation on the ECG.
Clinical signs
It is usually identified on electrocardiogram, often with left axis deviation and a characteristic QRS pattern. Clinical features vary; refer to documentation.
When to use this code
Use I44.4 when the provider documents left anterior fascicular block, left anterior hemiblock, or an equivalent ECG diagnosis. Code it when the finding is confirmed and part of the current record. If the chart only notes an abnormal ECG without naming the block, check documentation.
Do not use for
Do not use this code for nonspecific conduction abnormalities or other fascicular or bundle branch blocks. If the diagnosis is uncertain or undocumented, check documentation.
Coding tip
Assign I44.4 only when the provider clearly documents the specific left anterior fascicular block diagnosis.