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

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
2 inclusion terms · 1 Excludes1

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 308 — CARDIAC ARRHYTHMIA AND CONDUCTION DISORDERS WITH MCC (MDC 05)
  • MS-DRG 309 — CARDIAC ARRHYTHMIA AND CONDUCTION DISORDERS WITH CC (MDC 05)
  • MS-DRG 310 — CARDIAC ARRHYTHMIA AND CONDUCTION DISORDERS WITHOUT CC/MCC (MDC 05)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I45.5 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Sinoatrial block
  • Sinoauricular block

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Coder workflow for I45.5

MedCoder structured workflow — derived from this code’s own official record

Before you code I45.5

  1. “Other” (NEC) means the condition is specified in the record but no dedicated code captures it. Confirm the documented form is not one a sibling code names before settling on I45.5; if the record states no specifics at all, the unspecified sibling applies instead. “Other” codes are for documented conditions the classification gives no specific code; “unspecified” codes are for records lacking the detail (Guidelines I.A.9.a, I.A.9.b).

    ReviewI45.0, I45.2, I45.3, I45.4, I45.6

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with I45.5. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in I45.5’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewI45.9

Consider I45.5. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes1 — check before selecting I45.5(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with I45.5: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareI45.9

    See the official tabular notes · Guidelines I.A.12.a

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition I45.5 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewI45.9

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Other specified heart block is a billable ICD-10-CM diagnosis code (I45.5).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (11)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 3 MS-DRGs: DRG 308 (MDC 05), DRG 309 (MDC 05), DRG 310 (MDC 05).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):CIR016 — Conduction disorders (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Conduction disorders).

I44.30 — Unspecified atrioventricular block, I44.39 — Other atrioventricular block, I44.4 — Left anterior fascicular block, I44.5 — Left posterior fascicular block, I44.60 — Unspecified fascicular block, I44.69 — Other fascicular block, I44.7 — Left bundle-branch block, unspecified, I45.0 — Right fascicular block, I45.10 — Unspecified right bundle-branch block, I45.19 — Other right bundle-branch block, I45.2 — Bifascicular block, I45.3 — Trifascicular block, I45.4 — Nonspecific intraventricular block, I45.6 — Pre-excitation syndrome, I45.81 — Long QT syndrome, I45.89 — Other specified conduction disorders, I45.9 — Conduction disorder, unspecified, Z45.010 — Encounter for checking and testing of cardiac pacemaker pulse generator [battery], Z45.018 — Encounter for adjustment and management of other part of cardiac pacemaker, Z95.0 — Presence of cardiac pacemaker, +3 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Arrest, arrested”, “Sinus”, “Block, blocked”; these codes share that main term but sit in a different category of the Tabular List.

I44.0 — Atrioventricular block, first degree (heart, first degree), I44.1 — Atrioventricular block, second degree (Mobitz), I44.2 — Atrioventricular block, complete (third degree), I44.30 — Unspecified atrioventricular block (atrioventricular), I44.39 — Other atrioventricular block (atrioventricular, specified NEC), I44.4 — Left anterior fascicular block (fascicular, anterior), I44.5 — Left posterior fascicular block (fascicular, posterior), I44.60 — Unspecified fascicular block (fascicular), I44.69 — Other fascicular block (fascicular, specified NEC), I44.7 — Left bundle-branch block, unspecified (bundle-branch, left), I46.2 — Cardiac arrest due to underlying cardiac condition (cardiac, due to, cardiac condition), I46.8 — Cardiac arrest due to other underlying condition (cardiac, due to, specified condition NEC), I46.9 — Cardiac arrest, cause unspecified (cardiac), I47.19 — Other supraventricular tachycardia (tachycardia, paroxysmal), I49.89 — Other specified cardiac arrhythmias not elsewhere classified (arrhythmia), I81 — Portal vein thrombosis (portal), I82.0 — Budd-Chiari syndrome (hepatic vein), I82.90 — Acute embolism and thrombosis of unspecified vein (vein NOS), I97.12 — Postprocedural cardiac arrest (cardiac, postprocedural), I97.71 — Intraoperative cardiac arrest (cardiac, intraoperative), +42 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Iron Panel

Contextual Map

Every relationship of I45.5 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run I45.5 with this related code in Claim Check

Hierarchy

Excludes1

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 05 — Diseases and Disorders of the Circulatory System[MDC crossing]: “Diseases and Disorders of the Circulatory System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 17,209 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries (11)

  • Arborization block (heart)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Arrest, arrested, sinus[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Block, blocked, arborization (heart)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Block, blocked, heart, specified type NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Block, blocked, nodal[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Block, blocked, sinoatrial[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Block, blocked, sinoauricular[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Sinus, arrest[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 3 more

Nearest codes (13)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "I45.5 — Other specified heart block." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/i45.5-other-specified-heart-block

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Other specified heart block

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to I45.5 in its code family, with their registry titles.

View all codes in the I45 family