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ICD-10-CM 2027 diagnosis code

I23.6Thrombosis of atrium, auricular appendage, and ventricle as current complications following acute myocardial infarction

✓ Billable / specificCC — complication/comorbidityAdult · age 15–124

I23.6 is a valid, billable ICD-10-CM code for thrombosis of atrium, auricular appendage, and ventricle as current complications following acute myocardial infarction. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Thombos of atrium/auric append/ventr as current comp fol AMI

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I23.6

I23.6 is the ICD-10-CM diagnosis code for thrombosis of atrium, auricular appendage, and ventricle as current complications following acute myocardial infarction. It belongs to category I23 (certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)), block I20-I25 (ischemic heart diseases) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within I23 (certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)), I23.6 is specifically for thrombosis of atrium, auricular appendage, and ventricle as current complications following acute myocardial infarction. Related codes cover hemopericardium as current complication following acute myocardial infarction (I23.0), atrial septal defect as current complication following acute myocardial infarction (I23.1), ventricular septal defect as current complication following acute myocardial infarction (I23.2), rupture of cardiac wall without hemopericardium as current complication following acute myocardial infarction (I23.3), rupture of chordae tendineae as current complication following acute myocardial infarction (I23.4), rupture of papillary muscle as current complication following acute myocardial infarction (I23.5), Postinfarction angina (I23.7) and other current complications following acute myocardial infarction (I23.8).

Don't report I23.6 together with the conditions in its Excludes1 note: thrombosis of atrium, auricular appendage, and ventricle not specified as current complication following acute myocardial infarction (I51.3).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 314 (Other Circulatory System Diagnoses with MCC, relative weight 2.0873), DRG 315 (Other Circulatory System Diagnoses with CC, relative weight 0.9508) and DRG 316 (Other Circulatory System Diagnoses without CC/MCC, relative weight 0.6677), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

The Medicare Code Editor expects this diagnosis only for patients age 15 through 124.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 429.79 (certain sequelae of myocardial infarction, not elsewhere classified, other).

Coding notes

Excludes1Not coded here — never report together with this code
  • thrombosis of atrium, auricular appendage, and ventricle not specified as current complication following acute myocardial infarction (I51.3)

Notes that apply from higher levels

Instructions written at a parent level also apply to I23.6.

Broader instructions also apply from I20-I25 Ischemic heart diseases and Chapter 9: Diseases of the circulatory system.

Alphabetic index entries

7 entries

Terms in the official ICD-10-CM index that lead to I23.6.

Codes whose notes reference I23.6

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 429.79Certain sequelae of myocardial infarction, not elsewhere classified, otherapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about I23.6

Is I23.6 billable?

Yes. I23.6 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I23.6 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I23.6 as a principal diagnosis.

Is I23.6 a CC or MCC?

I23.6 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does I23.6 group to?

I23.6 is used in the MS-DRG v44.0 logic for MS-DRG 314 (Other Circulatory System Diagnoses with MCC), MS-DRG 315 (Other Circulatory System Diagnoses with CC) and MS-DRG 316 (Other Circulatory System Diagnoses without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for I23.6?

The CMS General Equivalence Mappings map I23.6 to ICD-9-CM 429.79.