ICD-10 Code I21.3

ST elevation (STEMI) myocardial infarction of unsp site

Diagnosis Code I21.3

ICD-10: I21.3
Short Description: ST elevation (STEMI) myocardial infarction of unsp site
Long Description: ST elevation (STEMI) myocardial infarction of unspecified site
Version 2019 of the ICD-10-CM diagnosis code I21.3

Valid for Submission
The code I21.3 is valid for submission for HIPAA-covered transactions.

Deleted Code
This code was deleted in the 2019 ICD-10 code set with the code(s) listed below. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2018. This code was replaced for the FY 2019 (October 1, 2018 - September 30, 2019).
  • I21.9 - Acute myocardial infarction, unspecified
  • I21.A1 - Myocardial infarction type 2
  • I21.A9 - Other myocardial infarction type

Code Classification
  • Diseases of the circulatory system (I00–I99)
    • Ischemic heart diseases (I20-I25)
      • Acute myocardial infarction (I21)
Version 2019 Replaced Code Billable Code

Information for Medical Professionals

Diagnostic Related Groups
The diagnosis code I21.3 is grouped in the following Diagnostic Related Group(s) (MS-DRG V35.0)

  • 222 - CARDIAC DEFIBRILLATOR IMPLANT WITH CARDIAC CATHETERIZATION WITH AMI/HF/SHOCK WITH MCC
  • 223 - CARDIAC DEFIBRILLATOR IMPLANT WITH CARDIAC CATHETERIZATION WITH AMI/HF/SHOCK WITHOUT MCC
  • 224 - CARDIAC DEFIBRILLATOR IMPLANT WITH CARDIAC CATHETERIZATION WITHOUT AMI/HF/SHOCK WITH MCC
  • 225 - CARDIAC DEFIBRILLATOR IMPLANT WITH CARDIAC CATHETERIZATION WITHOUT AMI/HF/SHOCK WITHOUT MCC
  • 226 - CARDIAC DEFIBRILLATOR IMPLANT WITHOUT CARDIAC CATHETERIZATION WITH MCC
  • 227 - CARDIAC DEFIBRILLATOR IMPLANT WITHOUT CARDIAC CATHETERIZATION WITHOUT MCC

Convert to ICD-9
  • 410.91 - AMI NOS, initial (Approximate Flag)

Synonyms
  • Acute Q wave infarction - widespread
  • Acute Q wave myocardial infarction
  • Acute ST segment elevation myocardial infarction
  • Acute widespread myocardial infarction
  • Postoperative myocardial infarction

Index to Diseases and Injuries
References found for the code I21.3 in the Index to Diseases and Injuries:

  • - STEMI - See Also: - Infarct, myocardium, ST elevation; - I21.3

Tabular List of Diseases and Injuries
References found for the code I21.3 in the Tabular List of Diseases and Injuries:

  • Inclusion Terms:
    • Acute transmural myocardial infarction of unspecified site
    • Transmural (Q wave) myocardial infarction NOS
    • Type 1 ST elevation myocardial infarction of unspecified site

Information for Patients


Heart Attack

Also called: MI, Myocardial infarction

Each year almost 800,000 Americans have a heart attack. A heart attack happens when blood flow to the heart suddenly becomes blocked. Without the blood coming in, the heart can't get oxygen. If not treated quickly, the heart muscle begins to die. But if you do get quick treatment, you may be able to prevent or limit damage to the heart muscle. That's why it's important to know the symptoms of a heart attack and call 9-1-1 if you or someone else is having them. You should call, even if you are not sure that it is a heart attack.

The most common symptoms in men and women are

  • Chest discomfort. It is often in center or left side of the chest. It usually lasts more than a few minutes. It may go away and come back. It can feel like pressure, squeezing, fullness, or pain. It also can feel like heartburn or indigestion.
  • Shortness of breath. Sometimes this is your only symptom. You may get it before or during the chest discomfort. It can happen when you are resting or doing a little bit of physical activity.
  • Discomfort in the upper body. You may feel pain or discomfort in one or both arms, the back, shoulders, neck, jaw, or upper part of the stomach.

You may also have other symptoms, such as nausea, vomiting, dizziness, and lightheadedness. You may break out in a cold sweat. Sometimes women will have different symptoms then men. For example, they are more likely to feel tired for no reason.

The most common cause of heart attacks is coronary artery disease (CAD). With CAD, there is a buildup of cholesterol and other material, called plaque, on their inner walls or the arteries. This is atherosclerosis. It can build up for years. Eventually an area of plaque can rupture (break open). A blood clot can form around the plaque and block the artery.

A less common cause of heart attack is a severe spasm (tightening) of a coronary artery. The spasm cuts off blood flow through the artery.

At the hospital, health care providers make a diagnosis based on your symptoms, blood tests, and different heart health tests. Treatments may include medicines and medical procedures such as coronary angioplasty. After a heart attack, cardiac rehabilitation and lifestyle changes can help you recover.

NIH: National Heart, Lung, and Blood Institute

  • Being active after your heart attack (Medical Encyclopedia)
  • Cardiac catheterization - discharge (Medical Encyclopedia)
  • Heart attack (Medical Encyclopedia)
  • Heart attack - discharge (Medical Encyclopedia)
  • Learn What a Heart Attack Feels Like--It Could Save Your Life - NIH - Easy-to-Read (National Heart, Lung, and Blood Institute)
  • Troponin test (Medical Encyclopedia)

[Read More]

ICD-10 Footnotes

General Equivalence Map Definitions
The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.

  • Approximate Flag - The approximate flag is on, indicating that the relationship between the code in the source system and the code in the target system is an approximate equivalent.
  • No Map Flag - The no map flag indicates that a code in the source system is not linked to any code in the target system.
  • Combination Flag - The combination flag indicates that more than one code in the target system is required to satisfy the full equivalent meaning of a code in the source system.

Index of Diseases and Injuries Definitions

  • And - The word "and" should be interpreted to mean either "and" or "or" when it appears in a title.
  • Code also note - A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
  • 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.
  • Type 1 Excludes Notes - 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.
  • Type 2 Excludes Notes - 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.
  • Includes Notes - This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
  • Inclusion terms - List of terms is included under some codes. 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.
  • NEC "Not elsewhere classifiable" - This abbreviation in the Alphabetic Index represents "other specified". When a specific code is not available for a condition, the Alphabetic Index directs the coder to the "other specified” code in the Tabular List.
  • NOS "Not otherwise specified" - This abbreviation is the equivalent of unspecified.
  • See - The "see" instruction following a main term in the Alphabetic Index indicates that another term should be referenced. It is necessary to go to the main term referenced with the "see" note to locate the correct code.
  • See Also - A "see also" instruction following a main term in the Alphabetic Index instructs that there is another main term that may also be referenced that may provide additional Alphabetic Index entries that may be useful. It is not necessary to follow the "see also" note when the original main term provides the necessary code.
  • 7th Characters - Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
  • With - The word "with" should be interpreted to mean "associated with" or "due to" when it appears in a code title, the Alphabetic Index, or an instructional note in the Tabular List. The word "with" in the Alphabetic Index is sequenced immediately following the main term, not in alphabetical order.

Present on Admission
The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement.

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