Cardiology ICD-10 Codes & CPT Codes

Accurate cardiology coding is critical for reimbursement and compliance. This reference covers the most-used ICD-10-CM diagnosis codes and CPT procedure codes for cardiology practices in the United States. Whether you are billing for hypertension management, echocardiography, or arrhythmia treatment, these codes reflect current CMS guidelines and are updated for the 2025-2026 fiscal year.

FY 2026 ICD-10-CM (CMS) · CPT codes updated annually · All codes verified billable

Top ICD-10 Codes for Cardiology

ICD-10 Code Description Billable
I10 Essential (primary) hypertension ✓
I25.10 Atherosclerotic heart disease of native coronary artery w/o angina ✓
I25.9 Chronic ischemic heart disease, unspecified ✓
I48.91 Unspecified atrial fibrillation ✓
I48.0 Paroxysmal atrial fibrillation ✓
I50.9 Heart failure, unspecified ✓
I50.22 Chronic systolic (congestive) heart failure ✓
I21.9 Acute myocardial infarction, unspecified ✓
I20.9 Angina pectoris, unspecified ✓
I42.9 Cardiomyopathy, unspecified ✓
I44.2 Atrioventricular block, complete ✓
I47.2 Ventricular tachycardia ✓
I49.9 Cardiac arrhythmia, unspecified ✓
I35.0 Nonrheumatic aortic (valve) stenosis ✓
I11.9 Hypertensive heart disease without heart failure ✓
R00.0 Tachycardia, unspecified ✓
R00.1 Bradycardia, unspecified ✓
R07.9 Chest pain, unspecified ✓
Z95.0 Presence of cardiac pacemaker ✓
Z82.49 Family history of ischemic heart disease and other diseases of the circulatory system ✓

Source: CMS ICD-10-CM Official Code Set FY 2026

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Common CPT Codes for Cardiology Billing

CPT Code Description
93000 Electrocardiogram, routine ECG with at least 12 leads; with interpretation and report
93306 Echocardiography, transthoracic, real-time with image documentation
93017 Cardiovascular stress test using maximal or submaximal treadmill/bicycle exercise
93010 Electrocardiogram, routine ECG; interpretation and report only
93880 Duplex scan of extracranial arteries; complete bilateral study
99213 Office or other outpatient visit, established patient, low complexity
99214 Office or other outpatient visit, established patient, moderate complexity

CPT descriptions are editorial summaries. Refer to the CMS Physician Fee Schedule for official rates.

Cardiology Billing & Coding Tips

  • Always specify laterality and acuity in MI coding — I21 codes differ by STEMI/NSTEMI and vessel site.
  • Atrial fibrillation has four billable subtypes (I48.0–I48.19, I48.2x, I48.91); query the physician before defaulting to I48.91.
  • Document the causal relationship explicitly when coding hypertensive heart disease (I11.x) to satisfy CMS medical necessity.
  • 93306 (echo) requires a separate interpretation report signed by the cardiologist to be billable under Part B.

Frequently Asked Questions

What is the ICD-10 code for atrial fibrillation?

The most common code is I48.91 (Unspecified atrial fibrillation). However, coders should specify the type when documented: I48.0 (Paroxysmal), I48.11/I48.19 (Persistent), I48.20/I48.21 (Chronic/Long-standing persistent), or I48.11 (Longstanding persistent).

Is I10 (essential hypertension) billable?

Yes. I10 is a valid, billable ICD-10-CM code. It is the primary diagnosis for essential (primary) hypertension and is accepted by all major payers.

What CPT code is used for an EKG?

93000 covers a routine ECG with interpretation and report. Use 93010 if you are only providing the interpretation (reading only, no tracing performed at your site).

How does OmniMD help with cardiology coding?

OmniMD’s Cardiology EHR embeds ICD-10 and CPT code suggestions directly into the encounter workflow, reducing manual lookup time and claim denial rates.

What is the difference between I25.10 and I25.9?

I25.10 specifies atherosclerotic heart disease of a native coronary artery without angina pectoris. I25.9 is a less-specific chronic ischemic heart disease code. Always code to the highest specificity supported by the documentation.

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