Other cardiac arrhythmias (I49) ICD-10-CM
The I49 code range covers other cardiac arrhythmias with 13 ICD-10-CM diagnosis codes. 10 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
- cardiac arrhythmia complicating:
- abortion or ectopic or molar pregnancy O00 O07 O08.8
- obstetric surgery and procedures O75.4
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Codes in the I49 Range 13 codes · 10 billable
- I49 Other cardiac arrhythmiasNon-billable
- I49.0 Ventricular fibrillation and flutterNon-billable
- I49.01 Ventricular fibrillation
- I49.02 Ventricular flutter
- I49.1 Atrial premature depolarization
- I49.2 Junctional premature depolarization
- I49.3 Ventricular premature depolarization
- I49.4 Other and unspecified premature depolarizationNon-billable
- I49.40 Unspecified premature depolarization
- I49.49 Other premature depolarization
- I49.5 Sick sinus syndrome
- I49.8 Other specified cardiac arrhythmias
- I49.9 Cardiac arrhythmia, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the I49 range.
Brugada Syndrome
An autosomal dominant defect of cardiac conduction that is characterized by an abnormal ST-segment in leads V1-V3 on the ELECTROCARDIOGRAM resembling a right BUNDLE-BRANCH BLOCK; high risk of VENTRICULAR TACHYCARDIA; or VENTRICULAR FIBRILLATION; SYNCOPAL EPISODE; and possible sudden death. This syndrome is linked to mutations of gene encoding the cardiac SODIUM CHANNEL alpha subunit.
Parasystole
A cardiac arrhythmia that is caused by interaction of two independently initiated cardiac impulses of different rates from two separate foci. Generally one focus is the SINOATRIAL NODE, the normal pacemaker. The ectopic focus is usually in the HEART VENTRICLE but can be in the HEART ATRIUM or the ATRIOVENTRICULAR NODE. Modulation of the parasystolic rhythm by the sinus rhythm depends on the completeness of entrance block surrounding the parasystolic focus.
Romano-Ward Syndrome
A form of long QT syndrome that is without congenital deafness. It is caused by mutation of the KCNQ1 gene which encodes a protein in the VOLTAGE-GATED POTASSIUM CHANNEL.
Sick Sinus Syndrome
A condition caused by dysfunctions related to the SINOATRIAL NODE including impulse generation (CARDIAC SINUS ARREST) and impulse conduction (SINOATRIAL EXIT BLOCK). It is characterized by persistent BRADYCARDIA, chronic ATRIAL FIBRILLATION, and failure to resume sinus rhythm following CARDIOVERSION. This syndrome can be congenital or acquired, particularly after surgical correction for heart defects.
Ventricular Fibrillation
A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.
Ventricular Flutter
A potentially lethal cardiac arrhythmia characterized by an extremely rapid, hemodynamically unstable ventricular tachycardia (150-300 beats/min) with a large oscillating sine-wave appearance. If untreated, ventricular flutter typically progresses to VENTRICULAR FIBRILLATION.
About the I49 Code Range
ICD-10 code I49 covers various other cardiac arrhythmias, which are irregular heart rhythms not classified elsewhere. This group includes conditions like ventricular fibrillation, ventricular flutter, premature heartbeats from different heart areas, sick sinus syndrome, and unspecified or other specified arrhythmias.
The ICD-10 codes for other cardiac arrhythmias detail arrhythmias such as I49.01 (ventricular fibrillation) and I49.02 (ventricular flutter), both life-threatening irregular rhythms sometimes called ventricular flutter or ventricular tachyarrhythmia. Premature depolarizations like I49.1 (atrial premature depolarization) and I49.3 (ventricular premature depolarization) are also included, commonly known as premature atrial contractions (PACs) or premature ventricular complexes (PVCs). The section further identifies I49.5 for sick sinus syndrome, a disorder of the heart's natural pacemaker. For arrhythmias without a more precise diagnosis, codes I49.8 and I49.9 classify other specified or unspecified cardiac arrhythmias. Recognizing synonyms like “ectopic beats,” “paroxysmal ventricular fibrillation,” or “tachycardia-bradycardia” helps medical coders choose the correct code when documentation references these common terms.
Questions About This Page
How many billable codes are in the I49 range?
Of the 13 codes in this range, 10 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the I49 range classify?
The range classifies other cardiac arrhythmias. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
