Make your practice more efficient. Get in touch with our Sales team today at (415) 993-4977.

ICD-10 Tips for Cardiologists

The clinical concepts for cardiology guide includes common ICD-10 codes, clinical documentation tips and clinical scenarios.

Specifying anatomical location and laterality required by ICD-10 is easier than you think.

This detail reflects how physicians and clinicians communicate and to what they pay attention. It is a matter of ensuring the information is captured in your documentation.

In ICD-10-CM, there are three main categories of changes:

  • Definition Changes
  • Terminology Differences
  • Increased Specificity

For cardiology, the focus is increased specificity and documenting the downstream effects of the patient’s condition


Definition Change

When documenting hypertension, include the following:

  1. Timeframe An AMI is now considered “acute” for 4 weeks from the time of the incident, a revised timeframe from the current ICD-9 period of 8 weeks.
  2. Episode of care ICD-10 does not capture episode of care (e.g. initial, subsequent, sequelae).
  3. Subsequent AMI ICD-10 allows coding of a new MI that occurs during the 4 week “acute period” of the original AMI.

ICD-10 Code Examples

I21.02 ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery
I21.4 Non-ST elevation (NSTEMI) myocardial infarction
I22.1 Subsequent ST elevation (STEMI) myocardial infarction of inferior wall


Definition Change
In ICD-10, hypertension is defined as essential (primary).
The concept of “benign or malignant” as it relates to hypertension no longer exists.
When documenting hypertension, include the following:

  1. Type e.g. essential, secondary, etc.
  2. Causal relationship e.g. Renal, pulmonary, etc.

ICD-10 Code Examples

I10 Essential (primary) hypertension
I11.9 Hypertensive heart disease without heart failure
I15.0 Renovascular hypertension


Terminology Differences & Increased Specificity
The terminology used in ICD-10 exactly matches the types of CHF. If you document “decompensation” or “exacerbation,” the CHF type will be coded as “acute on chronic.”
When documenting CHF, include the following:

  1. Cause e.g. Acute, chronic
  2. Severity e.g. Systolic, diastolic

ICD-10 Code Examples

I50.23 Acute on chronic systolic (congestive) heart failure
I50.33 Acute on chronic diastolic (congestive) heart failure
I50.43 Acute on chronic combined systolic (congestive) and diastolic (congestive) heart failure


Terminology Difference
Underdosing is an important new concept and term in ICD-10.
It allows you to identify when a patient is taking less of a medication than is prescribed.
When documenting underdosing, include the following:

  1. Intentional, Unintentional, Non-compliance Is the underdosing deliberate? (e.g., patient refusal)
  2. Reason Why is the patient not taking the medication? ( hardship, age-related debility)

ICD-10 Code Examples

Z91.120 Patient’s intentional underdosing of medication regimen due to financial hardship
T36.4x6A Underdosing of tetracyclines, initial encounter
T45.526D Underdosing of antithrombotic drugs, subsequent encounter


Terminology Difference When documenting atherosclerotic heart disease with angina pectoris, include the following:

  1. Cause Assumed to be atherosclerosis; notate if there is another cause
  2. Stability e.g. Stable angina pectoris, unstable angina pectoris
  3. Vessel Note which artery (if known) is involved and whether the artery is native or autologous
  4. Graft involvement If appropriate, whether a bypass graft was involved in the angina pectoris diagnosis; also note the original location of the graft and whether it is autologous or biologic

ICD-10 Code Examples

I25.110 Atherosclerotic heart disease of a native coronary artery with unstable angina pectoris
I25.710 Atherosclerosis of autologous vein coronary artery bypass graft(s) with unstable angina pectoris


Increased Specificity
When documenting cardiomyopathy, include the following, where appropriate:

  1. Type e.g. Dilated/congestive, obstructive or nonobstructive hypertrophic, etc.
  2. Location e.g. Endocarditis, right ventricle, etc.
  3. Cause e.g. Congenital, alcohol, etc. List cardiomyopathy seen in other diseases such as gout, amyloidosis, etc.

ICD-10 Code Examples

I42.0 Dilated cardiomyopathy
I42.1 Obstructive hypertrophic cardiomyopathy
I42.3 Endomyocardial (eosinophilic) disease


Increased Specificity
ICD-10 assumes heart valve diseases are rheumatic; if this is not the case, notate otherwise.
When documenting heart valve disease, include the following:

  1. Cause e.g. Rheumatic or non-rheumatic
  2. Type e.g. Prolapse, insufficiency, regurgitation, incompetence, stenosis, etc.
  3. Location e.g. Mitral valve, aortic valve, etc.

ICD-10 Code Examples

I06.2 Rheumatic aortic stenosis with insufficiency
I34.1 Nonrheumatic mitral (valve) prolapse


Increased Specificity
When documenting arrhythmias, include the following:

  1. Location e.g. Atrial, ventricular, supraventricular, etc.
  2. Rhythm name e.g. Flutter, fibrillation, type 1 atrial flutter, long QT syndrome, sick sinus syndrome, etc.
  3. Acuity e.g. Acute, chronic, etc.
  4. Cause e.g., Hyperkalemia, hypertension, alcohol consumption, digoxin, amiodarone, verapamil HCl

ICD-10 Code Examples

I48.2 Chronic atrial fibrillation
I49.01 Ventricular fibrillation