2026 ICD-10-CM Diagnosis Code I31.4Cardiac tamponade
I31.4 is a billable ICD-10-CM diagnosis code for cardiac tamponade. 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. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Pericarditis and pericardial disease.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for I31.4.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Cardiac tamponade
- Postoperative cardiac tamponade
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
- underlying cause
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Tamponade, heart - I31.4
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Cardiac
- tamponade
- Tamponade, heart
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Cardiac Tamponade
compression of the heart by accumulated fluid (pericardial effusion) or blood (hemopericardium) in the pericardium surrounding the heart. the affected cardiac functions and cardiac output can range from minimal to total hemodynamic collapse.
Patient EducationClinical
Pericardial Disorders
The pericardium is a membrane, or sac, that surrounds your heart. It holds the heart in place and helps it work properly. Problems with the pericardium include:
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Convert I31.4 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I31.4Overview
Is I31.4 (Other diseases of pericardium) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report cardiac tamponade on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I31.4 group to?
On inpatient claims, cardiac tamponade maps to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.
Can I31.4 be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because cardiac tamponade describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
What is the ICD-9 equivalent of I31.4?
Under the General Equivalence Mappings, cardiac tamponade converts to ICD-9-CM 423.3 (cardiac tamponade). The mapping is a direct match.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
