2021 ICD-10-CM Code I46.9

Cardiac arrest, cause unspecified

Version 2021
Billable Code
Unspecified Code
MS-DRG Mapping

Valid for Submission

I46.9 is a billable diagnosis code used to specify a medical diagnosis of cardiac arrest, cause unspecified. The code I46.9 is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.

The ICD-10-CM code I46.9 might also be used to specify conditions or terms like asystole, atrial standstill, cardiac arrest, cardiac arrest after obstetrical surgery and/or other procedure including delivery, cardiac arrest and/or failure following anesthesia and/or sedation in labor and/or delivery , cardiac arrest with successful resuscitation, etc.

Unspecified diagnosis codes like I46.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

ICD-10:I46.9
Short Description:Cardiac arrest, cause unspecified
Long Description:Cardiac arrest, cause unspecified

Code Classification

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code I46.9 are found in the index:

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Convert I46.9 to ICD-9 Code

The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code I46.9 its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.

Information for Patients


Cardiac Arrest

Also called: SCA, Sudden cardiac death

The heart has an internal electrical system that controls the rhythm of the heartbeat. Problems can cause abnormal heart rhythms, called arrhythmias. There are many types of arrhythmia. During an arrhythmia, the heart can beat too fast, too slow, or it can stop beating. Sudden cardiac arrest (SCA) occurs when the heart develops an arrhythmia that causes it to stop beating. This is different than a heart attack, where the heart usually continues to beat but blood flow to the heart is blocked.

There are many possible causes of SCA. They include coronary heart disease, physical stress, and some inherited disorders. Sometimes there is no known cause for the SCA.

Without medical attention, the person will die within a few minutes. People are less likely to die if they have early defibrillation. Defibrillation sends an electric shock to restore the heart rhythm to normal. You should give cardiopulmonary resuscitation (CPR) to a person having SCA until defibrillation can be done.

If you have had an SCA, an implantable cardiac defibrillator (ICD) reduces the chance of dying from a second SCA.

NIH: National Heart, Lung, and Blood Institute


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Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)