Other cardiac arrhythmias (I49) ICD-10-CM
The I49 code range covers other cardiac arrhythmias with 16 ICD-10-CM diagnosis codes. 12 of them are billable and valid for claim submission in fiscal year 2027, 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 16 codes · 12 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 arrhythmiasNon-billable
- I49.81 Brugada syndrome New
- I49.82 Ventricular bigeminy New
- I49.89 Other specified cardiac arrhythmias not elsewhere classified New
- 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.
Arrhythmias, Cardiac
Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.
Bradycardia
Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.
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.
Cardiac Complexes, Premature
A group of cardiac arrhythmias in which the cardiac contractions are not initiated at the SINOATRIAL NODE. They include both atrial and ventricular premature beats, and are also known as extra or ectopic heartbeats. Their frequency is increased in heart diseases.
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 Bigeminy by ECG Finding
An electrocardiographic finding of a normal QRS followed by a premature ventricular contraction; a rhythmic pairing of normal and atypical beats originating in the ventricles in a 1-1 ratio.
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
These conditions involve disturbances in the heart’s rhythm. The codes separate named rhythm conditions from premature beats and arrhythmias that are specified in another way or left unspecified.
I49.0 divides ventricular fibrillation from ventricular flutter. Premature depolarization codes distinguish atrial, junctional, and ventricular types, plus other or unspecified types. I49.5 identifies sick sinus syndrome. I49.8 branches into Brugada syndrome, ventricular bigeminy, and other specified arrhythmias. I49.9 is for an unspecified cardiac arrhythmia.
FY 2027 changes: The FY 2027 ICD-10-CM update, effective October 1, 2026, added I49.81, I49.82 and I49.89 and deleted I49.8.
Questions About This Page
How many billable codes are in the I49 range?
Of the 16 codes in this range, 12 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. 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 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
