2026 ICD-10-CM Diagnosis Code I51.3Intracardiac thrombosis, not elsewhere classified
ICD-10-CM Codes›I00–I99›I30-I5A›I51
- Billable — Valid for Submission
- Chronic Condition
I51.3 is a billable ICD-10-CM diagnosis code for intracardiac thrombosis, not elsewhere classified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 302 through 303. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined heart disease.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Arterial obstruction due to nonthrombotic embolism from heart
- Arterial obstruction due to thrombotic embolism from mural thrombus of heart
- Atrial thrombosis
- Disorder of left atrium as complication of procedure
- Disorder of right atrium as complication of procedure
- Intracardiac thrombosis in low output state
- Left ventricular thrombus
- Mural thrombus of atrium of heart
- Mural thrombus of heart
- Mural thrombus of left atrium
- Mural thrombus of left ventricle
- Mural thrombus of right atrium
- Mural thrombus of right ventricle
- Mural thrombus of ventricle of heart
- Occlusion of cutaneous microvasculature structure by cardiac embolus
- Occlusion of microvasculature of skin caused by embolus
- Post-infarction mural thrombus
- Right ventricular thrombus
- Thromboembolism due to mural thrombus
- Thrombotic embolism from cardiac atrium
- Thrombotic embolism from cardiac ventricle
- Thrombus of cardiac chamber
- Thrombus of left atrium
- Thrombus of physiologic left atrium as complication of procedure
- Thrombus of physiologic right atrium as complication of procedure
- Thrombus of right atrium
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Apical thrombosis (old)
- Atrial thrombosis (old)
- Auricular thrombosis (old)
- Mural thrombosis (old)
- Ventricular thrombosis (old)
Type 1 Excludes
- intracardiac thrombosis as current complication following acute myocardial infarction I23.6
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Clot (blood) - See Also: Embolism;
- heart - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- Embolism (multiple) (paradoxical) - I74.9
- cardiac - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- heart (fatty) - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel) - I82.90
- atrium, auricular - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- old - I51.3
- cardiac - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- old - I51.3
- endocardial - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- heart (chamber) - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- old - I51.3
- intracardiac NEC (apical) (atrial) (auricular) (ventricular) (old) - I51.3
- intramural - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- old - I51.3
- mural - See Also: Infarct, myocardium;
- not resulting in infarction - I51.3
- old - I51.3
- ventricle - See Also: Infarct, myocardium;
- old - I51.3
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- 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
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Coronary Artery Disease
Coronary artery disease (CAD) is the most common type of heart disease. It is the leading cause of death in the United States in both men and women.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I51.3 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I51.3Overview
Is I51.3 (Complications and ill-defined descriptions of heart disease) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report intracardiac thrombosis, not elsewhere classified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I51.3 group to?
When intracardiac thrombosis, not elsewhere classified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 302, 303, with relative weights from 0.6732 to 1.1966 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of I51.3?
Under the General Equivalence Mappings, intracardiac thrombosis, not elsewhere classified converts to ICD-9-CM 429.89 (ill-defined hrt dis NEC). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
