ICD-10 Code I48.11 – Longstanding persistent atrial fibrillation (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I48.11 – Longstanding persistent atrial fibrillation
What it is
I48.11 identifies atrial fibrillation that has continued for a long time and is no longer easily reversed. Use it when the record clearly states longstanding persistent atrial fibrillation.
Clinical signs
Clinical features vary; refer to documentation. Commonly, the rhythm is irregularly irregular, and the arrhythmia has persisted beyond the persistent phase without successful restoration of normal sinus rhythm.
When to use this code
Use this code when the provider documents longstanding persistent atrial fibrillation as the diagnosis. It may appear in cardiology notes, discharge summaries, or problem lists when the condition has been present for a prolonged period and remains ongoing. If the note only says atrial fibrillation, check documentation.
Do not use for
Do not use I48.11 for paroxysmal, persistent, or permanent atrial fibrillation unless the documentation specifically supports this subtype. Do not assume chronicity from anticoagulation or rate-control therapy alone.
Coding tip
Code the exact atrial fibrillation type stated by the provider; when the subtype is unclear, query for clarification.