I49.9 — Cardiac arrhythmia, unspecified

I49.9

ICD-10 Chapter 9: Circulatory System — illustrative image — Chapter 9: Diseases of the circulatory system (I00–I99) — illustrative image

What this code means

A cardiac arrhythmia is any abnormality of the heart's rhythm; the type is not specified here.

Also called: arrhythmia, cardiac arrhythmia, irregular heartbeat.

When this code is used

Used for cardiac arrhythmia, unspecified.

Where it sits in ICD-10-CM

Code I49.9 belongs to Chapter 9: Diseases of the circulatory system, which covers codes I00–I99 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.

Related symptoms

Palpitations

Related anatomy

Heart

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Frequently asked questions

What is ICD-10-CM code I49.9?

I49.9 is the ICD-10-CM diagnosis code for “Cardiac arrhythmia, unspecified”. A cardiac arrhythmia is any abnormality of the heart's rhythm; the type is not specified here.

When is code I49.9 used?

Used for cardiac arrhythmia, unspecified. It belongs to Chapter 9 of ICD-10-CM (Diseases of the circulatory system).

This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.