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ICD-10-CM 2027

ICD-10 code for heart complication

I51.9

Heart disease, unspecified

✓ Billable / specific

From the official ICD-10-CM alphabetic index entry “Complication (s) (from) (of) › heart”. Page updated September 29, 2026.

About coding heart complication

The ICD-10-CM code for heart complication is I51.9 (Heart disease, unspecified). The official index lists 36 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I51.9.

Within I51, choose I51.9 (Heart disease, unspecified) only when documentation doesn't support a more specific option: cardiac septal defect, acquired (I51.0), rupture of chordae tendineae, not elsewhere classified (I51.1), rupture of papillary muscle, not elsewhere classified (I51.2), intracardiac thrombosis, not elsewhere classified (I51.3), myocarditis, unspecified (I51.4), myocardial degeneration (I51.5), Cardiomegaly (I51.7) and other ill-defined heart diseases (I51.8).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 302 (Atherosclerosis with MCC, relative weight 1.1984) and DRG 303 (Atherosclerosis without MCC, relative weight 0.6612), 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.

More specific heart complication codes (official index)

  • assist device
  • infection and inflammation T82.7 — Infection and inflammatory reaction due to other cardiac and vascular devices, implants and grafts
  • following acute myocardial infarction
  • postoperative
  • transplant
  • and lung (s)
  • valve
  • graft (biological) T82.9 — Unspecified complication of cardiac and vascular prosthetic device, implant and graft
  • embolism T82.817 — Embolism due to cardiac prosthetic devices, implants and grafts
  • fibrosis T82.827 — Fibrosis due to cardiac prosthetic devices, implants and grafts
  • hemorrhage T82.837 — Hemorrhage due to cardiac prosthetic devices, implants and grafts
  • infection and inflammation T82.7 — Infection and inflammatory reaction due to other cardiac and vascular devices, implants and grafts
  • mechanical T82.228 — Other mechanical complication of biological heart valve graft
  • breakdown T82.221 — Breakdown (mechanical) of biological heart valve graft
  • displacement T82.222 — Displacement of biological heart valve graft
  • leakage T82.223 — Leakage of biological heart valve graft
  • malposition T82.222 — Displacement of biological heart valve graft
  • obstruction T82.228 — Other mechanical complication of biological heart valve graft
  • perforation T82.228 — Other mechanical complication of biological heart valve graft
  • protrusion T82.228 — Other mechanical complication of biological heart valve graft
  • pain T82.847 — Pain due to cardiac prosthetic devices, implants and grafts
  • specified type NEC T82.897 — Other specified complication of cardiac prosthetic devices, implants and grafts
  • stenosis T82.857 — Stenosis of other cardiac prosthetic devices, implants and grafts
  • thrombosis T82.867 — Thrombosis due to cardiac prosthetic devices, implants and grafts
  • prosthesis T82.9 — Unspecified complication of cardiac and vascular prosthetic device, implant and graft
  • embolism T82.817 — Embolism due to cardiac prosthetic devices, implants and grafts
  • fibrosis T82.827 — Fibrosis due to cardiac prosthetic devices, implants and grafts
  • hemorrhage T82.837 — Hemorrhage due to cardiac prosthetic devices, implants and grafts
  • infection or inflammation T82.6 — Infection and inflammatory reaction due to cardiac valve prosthesis
  • mechanical T82.09 — Other mechanical complication of heart valve prosthesis
  • breakdown T82.01 — Breakdown (mechanical) of heart valve prosthesis
  • displacement T82.02 — Displacement of heart valve prosthesis
  • leakage T82.03 — Leakage of heart valve prosthesis
  • malposition T82.02 — Displacement of heart valve prosthesis
  • obstruction T82.09 — Other mechanical complication of heart valve prosthesis
  • perforation T82.09 — Other mechanical complication of heart valve prosthesis
  • protrusion T82.09 — Other mechanical complication of heart valve prosthesis
  • pain T82.847 — Pain due to cardiac prosthetic devices, implants and grafts
  • specified type NEC T82.897 — Other specified complication of cardiac prosthetic devices, implants and grafts
  • mechanical T82.09 — Other mechanical complication of heart valve prosthesis
  • stenosis T82.857 — Stenosis of other cardiac prosthetic devices, implants and grafts
  • thrombosis T82.867 — Thrombosis due to cardiac prosthetic devices, implants and grafts

Common questions about heart complication ICD-10 codes

What is the ICD-10 code for heart complication?

I51.9 — Heart disease, unspecified. More specific codes apply when the documentation supports them: T82.7, T82.9, T82.817, T82.827 and others below.

Is I51.9 billable?

Yes. I51.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I51.9 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I51.9 as a principal diagnosis.

Is I51.9 a CC or MCC?

No. I51.9 is neither a CC nor an MCC under MS-DRG v44.0.