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ICD-10-CM 2027 diagnosis code

I45.6Pre-excitation syndrome

✓ Billable / specific

I45.6 is a valid, billable ICD-10-CM code for pre-excitation syndrome. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Lown-Ganong-Levine syndrome, ICD-10 code for Wolff-Parkinson-White syndrome, ICD-10 code for Accelerated atrioventricular conduction, ICD-10 code for Pre-excitation atrioventricular conduction.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I45.6

I45.6 is the ICD-10-CM diagnosis code for Pre-excitation syndrome. It belongs to category I45 (other conduction disorders), block I30-I5A (other forms of heart disease) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within I45 (other conduction disorders), I45.6 is specifically for Pre-excitation syndrome. Related codes cover right fascicular block (I45.0), other and unspecified right bundle-branch block (I45.1), Bifascicular block (I45.2), Trifascicular block (I45.3), nonspecific intraventricular block (I45.4), other specified heart block (I45.5), other specified conduction disorders (I45.8) and conduction disorder, unspecified (I45.9).

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 308 (Cardiac Arrhythmia and Conduction Disorders with MCC, relative weight 1.1806), DRG 309 (Cardiac Arrhythmia and Conduction Disorders with CC, relative weight 0.7316), DRG 310 (Cardiac Arrhythmia and Conduction Disorders without CC/MCC, relative weight 0.568), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 05 (Diseases and Disorders of the Circulatory System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 426.7 (anomalous atrioventricular excitation) and 426.81 (Lown-Ganong-Levine syndrome).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Accelerated atrioventricular conduction
  • Accessory atrioventricular conduction
  • Anomalous atrioventricular excitation
  • Lown-Ganong-Levine syndrome
  • Pre-excitation atrioventricular conduction
  • Wolff-Parkinson-White syndrome

Notes that apply from higher levels

Instructions written at a parent level also apply to I45.6.

Broader instructions also apply from Chapter 9: Diseases of the circulatory system.

Alphabetic index entries

7 entries

Terms in the official ICD-10-CM index that lead to I45.6.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

ICD-9-CM equivalent

Converter →
  • 426.7Anomalous atrioventricular excitationapproximate
  • 426.81Lown-Ganong-Levine syndromeapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about I45.6

Is I45.6 billable?

Yes. I45.6 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I45.6 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I45.6 as a principal diagnosis.

Is I45.6 a CC or MCC?

No. I45.6 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does I45.6 group to?

I45.6 is used in the MS-DRG v44.0 logic for MS-DRG 308 (Cardiac Arrhythmia and Conduction Disorders with MCC), MS-DRG 309 (Cardiac Arrhythmia and Conduction Disorders with CC), MS-DRG 310 (Cardiac Arrhythmia and Conduction Disorders without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for I45.6?

The CMS General Equivalence Mappings map I45.6 to ICD-9-CM 426.7 and 426.81.