2026 ICD-10-CM Diagnosis Code I51.81Takotsubo syndrome
ICD-10-CM Codes›I00–I99›I30-I5A›I51
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
I51.81 is a billable ICD-10-CM diagnosis code for takotsubo syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 34 closely related codes. Coders also document this condition as takotsubo cardiomyopathy. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined heart disease.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Takotsubo cardiomyopathy
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Reversible left ventricular dysfunction following sudden emotional stress
- Stress induced cardiomyopathy
- Takotsubo cardiomyopathy
- Transient left ventricular apical ballooning syndrome
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Cardiomyopathy (familial) (idiopathic) I42.9
stress induced I51.81
takotsubo I51.81
Syndrome See Also: Disease;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Takotsubo Cardiomyopathy
a transient left ventricular apical dysfunction or ballooning accompanied by electrocardiographic (ecg) t wave inversions. this abnormality is associated with high levels of catecholamines, either administered or endogenously secreted from a tumor or during extreme stress.
Patient EducationClinical
Cardiomyopathy
Cardiomyopathy is the name for diseases of the heart muscle. These diseases enlarge your heart muscle or make it thicker and more rigid than normal. In rare cases, scar tissue replaces the muscle tissue.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I51.81 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I51.81Overview
What is the ICD-10 code for takotsubo syndrome?
The ICD-10-CM code for takotsubo syndrome is I51.81 (sometimes written as I5181). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is I51.81 (Other ill-defined heart diseases) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report takotsubo syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I51.81 group to?
When takotsubo syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.
Is I51.81 a CC or MCC?
CMS lists I51.81 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 34 closely related codes in its exclusion list.
What is the ICD-9 equivalent of I51.81?
Under the General Equivalence Mappings, takotsubo syndrome converts to ICD-9-CM 429.83 (takotsubo syndrome). The mapping is a direct match.
