2025 ICD-10-CM Diagnosis Code I20.0

Unstable angina

• I20.0 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
• The 2025 edition of ICD-10-CM I20.0 became effective on October 1, 2024.
• This is the American ICD-10-CM version of I20.0 – other international versions of ICD-10 I20.0 may differ.

Applicable To

• Accelerated angina
• Crescendo angina
• De novo effort angina
• Intermediate coronary syndrome
• Preinfarction syndrome
• Worsening effort angina

The following code(s) above I20.0 contain annotation back-references

 that may be applicable to I20.0:

• I00-I99  Diseases of the circulatory system
• I20-I25  Ischemic heart diseases
• I20  Angina pectoris

Approximate Synonyms

• Preinfarction syndrome

Clinical Information

• Angina pectoris (or equivalent type of ischemic discomfort) which has recently changed in frequency, duration, intensity, or occurs at rest.
• Angina pectoris (or equivalent type of ischemic discomfort) with any 1 of the 3 following features: a) angina occurring at rest and prolonged, usually greater than 20 minutes; b) new onset angina of at least canadian cardiovascular society grading scale (or ccs classification system) classification severity iii or greater; c) recent acceleration in angina accentuated by an increase in severity of at least 1 ccs class to at least ccs class iii. The biomarkers of necrosis are below the threshold of myocardial infarction.
• Angina pectoris (or equivalent type of ischemic discomfort) with any 1 of the 3 following features: a) angina occurring at rest and prolonged, usually greater than 20 minutes; b) new onset angina of at least canadian cardiovascular society grading scale (or ccs classification system) classification severity iii or greater; c) recent acceleration in angina accentuated by an increase in severity of at least 1 ccs class to at least ccs class iii. The biomarkers of necrosis are below the threshold of myocardial infarction. (nih roadmap cardiovascular data standards working group)
• Precordial pain at rest, which may precede a myocardial infarction.

ICD-10-CM I20.0 is grouped within Diagnostic Related Group(s) (MS-DRG v42.0):

• 311 Angina pectoris

Convert I20.0 to ICD-9-CMCode History

• 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
• 2017 (effective 10/1/2016): No change
• 2018 (effective 10/1/2017): No change
• 2019 (effective 10/1/2018): No change
• 2020 (effective 10/1/2019): No change
• 2021 (effective 10/1/2020): No change
• 2022 (effective 10/1/2021): No change
• 2023 (effective 10/1/2022): No change
• 2024 (effective 10/1/2023): No change
• 2025 (effective 10/1/2024): No change

Code annotations containing back-references to I20.0:

• Type 1 Excludes: I25.110, I25.700, I25.720, I25.790, I25.710, I25.730

Diagnosis Index entries containing back-references to I20.0:

• Angina (attack) (cardiac) (chest) (heart) (pectoris) (syndrome) (vasomotor) I20.9
  • unstable I20.0
• Impending
  • coronary syndrome I20.0
  • myocardial infarction I20.0
• Infarct, infarction
  • impending I20.0 (myocardium)
• Syndrome – see also Disease
  • coronary
    • insufficiency or intermediate I20.0
  • impending coronary I20.0
  • intermediate coronary I20.0 (artery)
  • preinfarction I20.0