ICD-10-CM 2027
ICD-10 code for coronary sinus defect
From the official ICD-10-CM alphabetic index entry “Defect, defective › coronary sinus”. Page updated September 29, 2026.
About coding coronary sinus defect
The ICD-10-CM code for coronary sinus defect is Q21.13 (Coronary sinus atrial septal defect).
Within Q21.1 (atrial septal defect), Q21.13 is specifically for coronary sinus atrial septal defect. Related codes cover unspecified (Q21.10), secundum atrial septal defect (Q21.11), Patent foramen ovale (Q21.12), superior sinus venosus atrial septal defect (Q21.14), inferior sinus venosus atrial septal defect (Q21.15), sinus venosus atrial septal defect, unspecified (Q21.16) and other specified atrial septal defect (Q21.19).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 306 (Cardiac Congenital and Valvular Disorders with MCC, relative weight 1.546) and DRG 307 (Cardiac Congenital and Valvular Disorders without MCC, relative weight 0.9148), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about coronary sinus defect ICD-10 codes
What is the ICD-10 code for coronary sinus defect?
- Q21.13 — Coronary sinus atrial septal defect.
Is Q21.13 billable?
- Yes. Q21.13 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q21.13 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q21.13 as a principal diagnosis.
Is Q21.13 a CC or MCC?
- Q21.13 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.