ICD-10 I51.0
Billable / Specific CCCardiac septal defect, acquired
About ICD-10-CM I51.0
ICD-10-CM code I51.0 represents Cardiac septal defect, acquired. This is a billable/specific code in the Circulatory System chapter (block I51). The 2026 edition of ICD-10-CM I51.0 became effective on October 1, 2025.
Coding Tips for I51.0
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
I51.0 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under I51.0. Per CMS ICD-10-CM Tabular 2026.
- Acquired septal atrial defect (old)
- Acquired septal auricular defect (old)
- Acquired septal ventricular defect (old)
Type 1 Excludes
Pure excludes, these codes can never be coded together with I51.0. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- cardiac septal defect as current complication following acute myocardial infarction (I23.1, I23.2)
Inpatient DRG Impact, CC
codes Cardiac septal defect, acquired. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for I51.0
Local Coverage Determinations (LCDs) from CMS MACs that list I51.0 as a covered diagnosis.
Showing top 10 of 305 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing I51.0.
2 Aetna
2 Cigna
5 Medicare
CPT Codes Commonly Billed with I51.0
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Convert I51.0 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| I51.0 | 42971 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To I51.0
Other codes in section I30-I5A (Other forms of heart disease).
ICD-10 I51.0, Billing FAQ
Is ICD-10 code I51.0 billable? +
Yes, I51.0 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to I51.0? +
ICD-10 I51.0 includes: Acquired septal atrial defect (old); Acquired septal auricular defect (old); Acquired septal ventricular defect (old).
What codes are Type 1 Excludes for I51.0? +
Type 1 Excludes (never code together with I51.0): cardiac septal defect as current complication following acute myocardial infarction (I23.1, I23.2)
Is I51.0 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What ICD-9 codes does I51.0 map to? +
Per CMS GEMs, I51.0 maps to ICD-9 codes: 42971. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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