ICD-10 Code I23.1 – Atrial septal defect as current complication following acute myocardial infarction (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I23.1 – Atrial septal defect as current complication following acute myocardial infarction
What it is
This code identifies an atrial septal defect that occurs as a current complication after an acute myocardial infarction. Use it when the heart attack has led to an abnormal opening between the atria.
Clinical signs
Clinical features vary; refer to documentation. Records may note a post-infarction interatrial communication, left-to-right shunt, new murmur, or hemodynamic compromise after myocardial infarction.
When to use this code
Use I23.1 when the provider documents an atrial septal defect as an active complication of a recent acute MI. This applies to post-infarction septal rupture or similar interatrial defect described as current. If the defect is congenital, historical, or unrelated to the MI, do not assign this code.
Do not use for
Do not use this code for congenital atrial septal defect or for other septal defects without a documented acute MI complication. Check documentation if the record only mentions a murmur or unspecified cardiac shunt.
Coding tip
Link the defect explicitly to the acute myocardial infarction in the provider note before assigning I23.1.