Atypical atrial flutter

This code represents a form of atrial flutter that deviates from the typical "sawtooth" pattern seen in common atrial flutter. It often involves re-entrant circuits that are not confined to the cavotricuspid isthmus, leading to variable P-wave morphologies and cycle lengths. This atypical presentation can make diagnosis and treatment more challenging.

Use this code when documentation specifically identifies atrial flutter as "atypical," "non-isthmus dependent," or describes characteristics inconsistent with typical atrial flutter (e.g., left atrial flutter, incisional flutter). Supporting documentation should include electrophysiological study findings or detailed ECG interpretations noting the atypical features.

• Differentiate from typical atrial flutter (I48.3) based on electrophysiological findings or explicit physician documentation of "atypical."
• Do not use this code for atrial fibrillation (I48.0, I48.1, I48.2) or unspecified atrial flutter (I48.91).
• Ensure the medical record clearly supports the "atypical" designation, as this impacts treatment strategies.