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v1.0.0
ICD-10 Guide
DiagnosesAngina At Rest

Angina At Rest

ICD-10 Coding for Angina at Rest(I20.0, I25.110)

PRIMARY SPECIALTYCardiology
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Angina At Rest?
Essential facts and insights about Angina at Rest

Key Clinical Considerations:

  • Chest pain or discomfort that occurs at rest, typically lasting more than 10 minutes.
  • Symptoms may include shortness of breath, fatigue, or nausea accompanying chest pain.
  • Physical examination may reveal signs of cardiovascular distress, such as elevated blood pressure or abnormal heart sounds.
  • Diagnostic tests such as an electrocardiogram (ECG) may show ST-segment changes during episodes of angina.
  • Severity is often assessed based on frequency and duration of episodes, as well as response to nitroglycerin.

Clinical Information

Clinical Criteria & Documentation Requirements

  • Document the patient's history of angina, including frequency and triggers of episodes.
  • Use specific terminology such as 'angina at rest' or 'unstable angina' in the medical record.
  • Examples include: 'Patient reports episodes of chest pain at rest occurring 3 times a week.'
  • Medical necessity must be established, indicating why the diagnosis warrants treatment.
  • Quality measures may include documentation of risk factors and treatment plans.

Coding Guidelines

Usage Guidelines & Examples

  • Use I20.0 for unstable angina at rest; use I25.110 for stable angina with a history of myocardial infarction.
  • Do not use I20.0 for stable angina or angina due to non-cardiac causes.
  • I20.9 (Angina, unspecified) may be used when the specific type of angina is not documented.
  • Common errors include misclassifying stable angina as unstable; ensure clinical context is clear.
  • In complex cases, consider the patient's full clinical picture and any co-existing conditions.

Code Exclusions

Important Exclusions

  • Exclude I20.9 for unspecified angina when the type is known.
  • Alternative codes for excluded conditions include I21 (Acute myocardial infarction) for acute events.
  • Conditions are excluded to ensure accurate representation of the patient's clinical status.
  • Avoid confusion with I20.1, which specifies angina due to coronary artery spasm.
  • Related conditions like stable angina should be documented separately.

Related ICD-10 Codes

Primary Codes
I20.0
Unstable angina
I25.110
Atherosclerotic heart disease of native coronary artery with unstable angina
Ancillary Codes
Z79.84
Differential Codes
I20.1
I20.1
if coronary spasm is confirmed.
I25.119
I25.119
if angina type is not specified.

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Cardiology

Specialty Applications

  • Patients with known coronary artery disease or risk factors for heart disease.
  • Typically affects adults, particularly those over 50, with higher prevalence in males.
  • Clinical settings include outpatient cardiology clinics and emergency departments.
  • Relevant for cardiology specialists and primary care providers managing heart disease.
  • Treatment contexts include medication management and potential surgical interventions.

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Template 1

Template: 'Patient diagnosed with angina at rest based on clinical findings of chest pain.'

Template 2

Template: 'Clinical presentation consistent with unstable angina including prolonged chest pain.'

Template 3

Template: 'Diagnostic criteria for unstable angina met as evidenced by ECG changes.'

Template 4

Template: 'Treatment plan initiated for angina at rest with nitrates and beta-blockers.'

Template 5

Template: 'Follow-up care for angina at rest including monitoring of symptoms and medication adherence.'

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What documentation is required for this diagnosis?

Document the patient's symptoms, duration, and frequency of angina episodes.

How does this differ from similar diagnoses?

Unstable angina occurs at rest and is more severe than stable angina.

What are common billing considerations?

Ensure medical necessity is clearly documented to support claims.

What procedures are typically associated?

CPT codes for stress tests, angiography, and medication management may apply.

Are there any quality reporting implications?

Quality measures may include monitoring of risk factors and treatment outcomes.