2027 ICD-10-CM Diagnosis Code I45.5Other specified heart block

ICD-10-CM Codes›I00–I99›I30-I5A›I45

ICD-10-CM I45.5
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I45.5 is a billable ICD-10-CM diagnosis code for other specified heart block. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 308 through 310. Coders also document this condition as ECG: partial sinoatrial block. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Conduction disorders.

Code Identity

ICD-10-CM Code
I45.5
Billable Status
Yes — Valid for Submission
Code Describes
Other specified heart block
Short Description
Other specified heart block
Same as the full description in the CMS dataset.
Parent Code
I45
Other conduction disorders

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI45Other conduction disorders
This CodeI45.5Other specified heart block

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • ECG: partial sinoatrial block
  • EKG: complete sinoatrial block
  • Progressive familial heart block
  • Progressive familial heart block, type II
  • Sinoatrial arrest with nodal/ventricular escape
  • Sinoatrial block
  • Sinus arrest
  • Sinus arrest with atrial escape
  • Sinus arrest with junctional escape
  • Sinus arrest with ventricular escape

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I45.5: its own notes plus those printed at Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Sinoatrial block
  • Sinoauricular block

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR016
Conduction disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Arrhythmia

An arrhythmia is a problem with the rate or rhythm of your heartbeat. Your heart beats too quickly, too slowly, or with an irregular pattern. Changes in the electrical signals that control your heartbeat cause arrhythmias.

The full article covers:

  • What is an arrhythmia?
  • What causes an arrhythmia?
  • What are the symptoms of an arrhythmia?
  • How is an arrhythmia diagnosed?
  • What are the treatments for an arrhythmia?
  • Can arrhythmias be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I45.5 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
426.6 Other heart block
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I45.5Overview

What is the ICD-10 code for other specified heart block?

The ICD-10-CM code for other specified heart block is I45.5 (sometimes written as I455). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I45.5 (Other conduction disorders) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified heart block on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I45.5 group to?

When other specified heart block is the principal diagnosis on an inpatient stay, it groups to MS-DRG 309, 310, 308, with relative weights from 0.5686 to 1.1809 depending on complications. Higher weights mean higher Medicare reimbursement.

Can I45.5 be reported with I45.9?

Not as a rule. The Excludes1 note on I45.5 lists "heart block NOS (I45.9)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of I45.5?

Under the General Equivalence Mappings, other specified heart block converts to ICD-9-CM 426.6 (other heart block). The mapping is a direct match.