2027 ICD-10-CM Diagnosis Code R00.1Bradycardia, unspecified

ICD-10-CM Codes›R00–R99›R00-R09›R00

ICD-10-CM R00.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

R00.1 is a billable ICD-10-CM diagnosis code for bradycardia, unspecified. 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. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Circulatory signs and symptoms.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such abnormalities of heart rhythm.

Code Identity

ICD-10-CM Code
R00.1
Billable Status
Yes — Valid for Submission
Code Describes
Bradycardia, unspecified
Short Description
Bradycardia, unspecified
Same as the full description in the CMS dataset.
Parent Code
R00
Abnormalities of heart beat

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR00-R09Symptoms and signs involving the circulatory and respiratory systems
CategoryR00Abnormalities of heart beat
This CodeR00.1Bradycardia, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal pulse rate
  • Asymptomatic bradycardia
  • Borderline slow pulse
  • Bradycardia
  • Bradycardic cardiac arrest
  • Drug-induced bradycardia
  • Finding of pulse rate
  • Persistent sinus bradycardia
  • Pulse slow
  • Reflex bradycardia
  • Severe sinus bradycardia
  • Sinus bradycardia
  • Sinus bradycardia caused by drug
  • Sinus bradycardia due to metabolic disease
  • Symptomatic sinus bradycardia
  • Vagal autonomic bradycardia
  • Vagal autonomic bradycardia of prematurity

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to R00.1: its own notes plus those printed at R00 and Chapter 18. 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 bradycardia
  • Sinus bradycardia
  • Slow heart beat
  • Vagal bradycardia

Excludes1

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

On R00.1 itself
From R00 Abnormalities of heart beat applies to 5 codes
  • abnormalities originating in the perinatal period (P29.1-)

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 R00 Abnormalities of heart beat applies to 5 codes
  • specified arrhythmias (I47-I49)
From Chapter 18 (R00-R99) Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified applies to 774 codes
  • abnormal findings on antenatal screening of mother (O28.-)
  • certain conditions originating in the perinatal period (P04-P96)
  • signs and symptoms classified in the body system chapters
  • signs and symptoms of breast (N63, N64.5)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)

Notes

General instructions on how these codes are used.

From Chapter 18 (R00-R99) Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified applies to 774 codes
  • This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.
  • Signs and symptoms that point rather definitely to a given diagnosis have been assigned to a category in other chapters of the classification. In general, categories in this chapter include the less well-defined conditions and symptoms that, without the necessary study of the case to establish a final diagnosis, point perhaps equally to two or more diseases or to two or more systems of the body. Practically all categories in the chapter could be designated 'not otherwise specified', 'unknown etiology' or 'transient'. The Alphabetical Index should be consulted to determine which symptoms and signs are to be allocated here and which to other chapters. The residual subcategories, numbered .8, are generally provided for other relevant symptoms that cannot be allocated elsewhere in the classification.
  • The conditions and signs or symptoms included in categories R00-R94 consist of:
  • (a) cases for which no more specific diagnosis can be made even after all the facts bearing on the case have been investigated;
  • (b) signs or symptoms existing at the time of initial encounter that proved to be transient and whose causes could not be determined;
  • (c) provisional diagnosis in a patient who failed to return for further investigation or care;
  • (d) cases referred elsewhere for investigation or treatment before the diagnosis was made;
  • (e) cases in which a more precise diagnosis was not available for any other reason;
  • (f) certain symptoms, for which supplementary information is provided, that represent important problems in medical care in their own right.

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name R00.1, its category, or a range that includes it.

Excludes2 4

These codes carry an Excludes2 note naming R00.1: its condition is not part of those codes, and both may be reported when the patient has both.

  • I49 Other cardiac arrhythmias
    bradycardia NOS (R00.1)
  • I49 Other cardiac arrhythmias
    sinoatrial bradycardia (R00.1)
  • I49 Other cardiac arrhythmias
    sinus bradycardia (R00.1)
  • I49 Other cardiac arrhythmias
    vagal bradycardia (R00.1)

Use Additional Code 1

These codes say to use an additional code from the note, and R00.1 is one of the codes named.

  • T65.85 Toxic effect of medetomidine
    bradycardia NOS (R00.1)

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 SYM012
Circulatory signs and symptoms
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Bradycardia

    cardiac arrhythmias that are characterized by excessively slow heart rate, usually below 50 beats per minute in human adults. they can be classified broadly into sinoatrial node dysfunction and atrioventricular block.

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 R00.1 to ICD-9-CMHistory

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

ICD-9-CM
427.81 Sinoatrial node dysfunct
Approximate The match is approximate rather than exact.
ICD-9-CM
427.89 Cardiac dysrhythmias NEC
Approximate The match is approximate rather than exact.

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 R00.1Overview

What is the ICD-10 code for bradycardia, unspecified?

The ICD-10-CM code for bradycardia, unspecified is R00.1 (sometimes written as R001). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is R00.1 (Abnormalities of heart beat) a billable code?

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

What MS-DRG does R00.1 group to?

When bradycardia, unspecified 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 R00.1 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the bradycardia, unspecified is established, that condition takes the principal position instead.

Can R00.1 be reported with P29.12?

Not as a rule. The Excludes1 note on R00.1 lists "neonatal bradycardia (P29.12)". 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).