ICD-10-CM 2027 diagnosis code
I51.3Intracardiac thrombosis, not elsewhere classified
I51.3 is a valid, billable ICD-10-CM code for intracardiac thrombosis, not elsewhere classified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
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 I51.3
I51.3 is the ICD-10-CM diagnosis code for intracardiac thrombosis, not elsewhere classified. It belongs to category I51 (complications and ill-defined descriptions of heart disease), block I30-I5A (other forms of heart disease) 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 I51 (complications and ill-defined descriptions of heart disease), I51.3 is specifically for intracardiac thrombosis, not elsewhere classified. Related codes cover cardiac septal defect, acquired (I51.0), rupture of chordae tendineae, not elsewhere classified (I51.1), rupture of papillary muscle, not elsewhere classified (I51.2), myocarditis, unspecified (I51.4), myocardial degeneration (I51.5), Cardiomegaly (I51.7), other ill-defined heart diseases (I51.8) and heart disease, unspecified (I51.9).
Don't report I51.3 together with the conditions in its Excludes1 note: intracardiac thrombosis as current complication following acute myocardial infarction (I23.6).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 302 (Atherosclerosis with MCC, relative weight 1.1984) and DRG 303 (Atherosclerosis without MCC, relative weight 0.6612), 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.
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 429.89 (other ill-defined heart diseases).
Coding notes
- Apical thrombosis (old)
- Atrial thrombosis (old)
- Auricular thrombosis (old)
- Mural thrombosis (old)
- Ventricular thrombosis (old)
- intracardiac thrombosis as current complication following acute myocardial infarction (I23.6)
Notes that apply from higher levels
Instructions written at a parent level also apply to I51.3.
Broader instructions also apply from Chapter 9: Diseases of the circulatory system.
Alphabetic index entries
17 entriesTerms in the official ICD-10-CM index that lead to I51.3.
- Clot (blood) › heart › not resulting in infarction
- Embolism (multiple) (paradoxical) › cardiac › not resulting in infarction
- Embolism (multiple) (paradoxical) › heart (fatty) › not resulting in infarction
- Ischemia, ischemic › myocardium, myocardial (chronic or with a stated duration of over 4 weeks) › acute, without myocardial infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › atrium, auricular › not resulting in infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › atrium, auricular › old
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › cardiac › not resulting in infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › cardiac › old
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › endocardial › not resulting in infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › heart (chamber) › not resulting in infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › heart (chamber) › old
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › intracardiac NEC (apical) (atrial) (auricular) (ventricular) (old)
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › intramural › not resulting in infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › intramural › old
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › mural › not resulting in infarction
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › mural › old
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) › ventricle › old
Codes whose notes reference I51.3
- I23.6Excludes1
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.
MDC 05 · Diseases and Disorders of the Circulatory System
ICD-9-CM equivalent
Converter →- 429.89Other ill-defined heart diseasesapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about I51.3
Is I51.3 billable?
- Yes. I51.3 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I51.3 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I51.3 as a principal diagnosis.
Is I51.3 a CC or MCC?
- No. I51.3 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does I51.3 group to?
- I51.3 is used in the MS-DRG v44.0 logic for MS-DRG 302 (Atherosclerosis with MCC) and MS-DRG 303 (Atherosclerosis without 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 I51.3?
- The CMS General Equivalence Mappings map I51.3 to ICD-9-CM 429.89.