2026 ICD-10-CM Diagnosis Code R00.0Tachycardia, unspecified

ICD-10-CM CodesR00–R99R00-R09R00

ICD-10-CM R00.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R00.0 is a billable ICD-10-CM diagnosis code for tachycardia, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) 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
R00.0
Billable Status
Yes — Valid for Submission
Code Describes
Tachycardia, unspecified
Short Description
Tachycardia, unspecified
Same as the full description in the CMS dataset.
Parent Code
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 CodeR00.0Tachycardia, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal pulse rate
  • Borderline fast pulse
  • Cardiac pacemaker re-entrant tachycardia
  • Finding of pulse rate
  • Irregular tachycardia
  • Pacemaker mediated tachycardia
  • Persistent tachycardia during pregnancy
  • Pulse fast
  • QRS complex - finding
  • Reflex tachycardia
  • Regular wide QRS complex tachycardia
  • Sinoatrial node tachycardia
  • Sinus tachycardia
  • Stable tachyarrhythmia
  • Tachyarrhythmia
  • Tachycardia
  • Tachycardia-induced cardiomyopathy
  • Wide QRS complex

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Rapid heart beat
  • Sinoauricular tachycardia NOS
  • Sinus sinusal tachycardia NOS

Type 1 Excludes

  • inappropriate sinus tachycardia, so stated I47.11
  • neonatal tachycardia P29.11
  • paroxysmal tachycardia I47

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Fast pulse
    • Heart beat
      • rapid
    • Pulse
      • fast
    • Pulse
      • rapid
    • Rapid
      • heart (beat)
    • Sinus
      • tachycardia
    • Tachycardia
    • Tachycardia
      • sinoauricular NOS
    • Tachycardia
      • sinus [sinusal] NOS

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

  • Polymorphic Catecholaminergic Ventricular Tachycardia

    an arrhythmogenic disorder of the heart characterized by irregular heart rhythms in response to physical activity, stress, or catecholamine infusion, often transitioning into ventricular fibrillation.
  • Postural Orthostatic Tachycardia Syndrome

    a syndrome of orthostatic intolerance combined with excessive upright tachycardia, and usually without associated orthostatic hypotension. all variants have in common an excessively reduced venous return to the heart (central hypovolemia) while upright.
  • Tachycardia

    abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.
  • Tachycardia, Atrioventricular Nodal Reentry

    abnormally rapid heartbeats caused by reentry of atrial impulse into the dual (fast and slow) pathways of atrioventricular node. the common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid heart rate of 150-250 beats per minute.
  • Tachycardia, Ectopic Atrial

    abnormally rapid heartbeats originating from one or more automatic foci (nonsinus pacemakers) in the heart atrium but away from the sinoatrial node. unlike the reentry mechanism, automatic tachycardia speeds up and slows down gradually. the episode is characterized by a heart rate between 135 to less than 200 beats per minute and lasting 30 seconds or longer.
  • Tachycardia, Ectopic Junctional

    a rare form of supraventricular tachycardia caused by automatic, not reentrant, conduction initiated from sites at the atrioventricular junction, but not the atrioventricular node. it usually occurs during myocardial infarction, after heart surgery, or in digitalis intoxication with a heart rate ranging from 140 to 250 beats per minute.
  • Tachycardia, Paroxysmal

    abnormally rapid heartbeats with sudden onset and cessation.
  • Tachycardia, Reciprocating

    abnormally rapid heartbeats caused by reentrant conduction over the accessory pathways between the heart atria and the heart ventricles. the impulse can also travel in the reverse direction, as in some cases, atrial impulses travel to the ventricles over the accessory pathways and back to the atria over the bundle of his and the atrioventricular node.
  • Tachycardia, Sinoatrial Nodal Reentry

    abnormally rapid heartbeats caused by reentry circuit in or around the sinoatrial node. it is characterized by sudden onset and offset episodes of tachycardia with a heart rate of 100-150 beats per minute. the p wave is identical to the sinus p wave but with a longer pr interval.
  • Tachycardia, Sinus

    simple rapid heartbeats caused by rapid discharge of impulses from the sinoatrial node, usually between 100 and 180 beats/min in adults. it is characterized by a gradual onset and termination. sinus tachycardia is common in infants, young children, and adults during strenuous physical activities.
  • Tachycardia, Supraventricular

    a generic expression for any tachycardia that originates above the bundle of his.
  • Tachycardia, Ventricular

    an abnormally rapid ventricular rhythm usually in excess of 150 beats per minute. it is generated within the ventricle below the bundle of his, either as autonomic impulse formation or reentrant impulse conduction. depending on the etiology, onset of ventricular tachycardia can be paroxysmal (sudden) or nonparoxysmal, its wide qrs complexes can be uniform or polymorphic, and the ventricular beating may be independent of the atrial beating (av dissociation).
  • Ventricular Fibrillation

    a potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in heart ventricles. such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (syncope). it is one of the major electrocardiographic patterns seen with cardiac arrest.
  • Heart Rate

    the number of times the heart ventricles contract per unit of time, usually per minute.
  • Sinoatrial Node

    the small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (vena cava, superior) and right atrium. contraction impulses probably start in this node, spread over the atrium (heart atrium) and are then transmitted by the atrioventricular bundle (bundle of his) to the ventricle (heart ventricle).
  • Bundle of His

    small band of specialized cardiac muscle fibers that originates in the atrioventricular node and extends into the membranous part of the interventricular septum. the bundle of his, consisting of the left and the right bundle branches, conducts the electrical impulses to the heart ventricles in generation of myocardial contraction.
  • Fetal Tachyarrhythmia

    an abnormality in the fetal heart rhythm associated with an increase in fetal heart rate above 160 beats per minute.
  • Grade 1 Neonatal Tachyarrhythmia, AE|Grade 1 Neonatal Tachyarrhythmia|Grade 1 Neonatal Tachyarrhythmia, Adverse Event

    an adverse event in a newborn characterized by brief, self-limiting, episodes of asymptomatic tachyarrhythmia (e.g. extra-systolic beats); no care changes.
  • Grade 2 Neonatal Tachyarrhythmia, AE|Grade 2 Neonatal Tachyarrhythmia|Grade 2 Neonatal Tachyarrhythmia, Adverse Event

    a tachyarrhythmia adverse event in a newborn characterized by no change in age-appropriate behavior; requiring minor care changes (e.g. increased monitoring).
  • Grade 3 Neonatal Tachyarrhythmia, AE|Grade 3 Neonatal Tachyarrhythmia|Grade 3 Neonatal Tachyarrhythmia, Adverse Event

    a tachyarrhythmia adverse event in a newborn resulting in non-life threatening hemodynamic compromise or changes in age-appropriate behavior; requiring major care changes (e.g. new medication or intervention).
  • Grade 4 Neonatal Tachyarrhythmia, AE|Grade 4 Neonatal Tachyarrhythmia|Grade 4 Neonatal Tachyarrhythmia, Adverse Event

    a tachyarrhythmia adverse event in a newborn characterized by life-threatening consequences (e.g. shock); requiring urgent major care changes.
  • Grade 5 Neonatal Tachyarrhythmia, AE|Grade 5 Neonatal Tachyarrhythmia|Grade 5 Neonatal Tachyarrhythmia, Adverse Event

    a tachyarrhythmia adverse event in a newborn which results in death.
  • Neonatal Tachyarrhythmia, AE|Neonatal Tachyarrhythmia|Neonatal Tachyarrhythmia, Adverse Event|Neonatal tachyarrhythmia

    an adverse event in a newborn characterized by non-sinus rhythm with an abnormally high heart rate for age.
  • Supraventricular Tachyarrhythmia ECG Assessment|SPRTARRY|SPRTARRY|Supraventricular Tachyarrhythmias|Supraventricular Tachyarrhythmias|Supraventricular Tachyarrhythmias

    an electrocardiographic assessment of the abnormally fast cardiac rhythms originating above the ventricles.
  • Supraventricular Tachyarrhythmia Other than Atrial Fibrillation or Atrial Flutter Associated with Post-Acute Sequelae of SARS-CoV-2 Infection|PASC Supraventricular Tachyarrhythmia Other than Atrial Fibrillation or Atrial Flutter|PASC supraventricular tachyarrhythmia other than AF or atrial flutter|Post-Acute Sequelae of COVID-19 Supraventricular Tachyarrhythmia Other than Atrial Fibrillation or Atrial Flutter

    supraventricular tachycardia other than atrial fibrillation or atrial flutter in a patient without prior history of atrial tachyarrhythmias that started during probable or confirmed acute covid-19 and persisted beyond four weeks after the initial diagnosis of covid-19.
  • Sustained Atrial Tachyarrhythmia Related to COVID-19 other than Atrial Fibrillation or Atrial Flutter|Sustained atrial tachyarrhythmia other than AF or atrial flutter

    a supraventricular tachycardia, including av nodal re-entry, orthodromic re-entrant tachycardia, multifocal atrial tachycardia, other atrial tachycardia that lasts more then 30 seconds in a patient with probable or confirmed acute covid-19.
  • Tachyarrhythmia

    a disorder characterized by an arrhythmia with an above normal rate.
  • Ventricular Tachyarrhythmia ECG Assessment|VTTARRY|VTTARRY|Ventricular Tachyarrhythmias|Ventricular Tachyarrhythmias|Ventricular Tachyarrhythmias

    an electrocardiographic assessment of the abnormally fast cardiac rhythms originating within the ventricles.

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 R00.0 to ICD-9-CMHistory

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

ICD-9-CM
785.0 Tachycardia NOS
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R00.0Overview

Is R00.0 (Abnormalities of heart beat) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report tachycardia, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R00.0 group to?

When tachycardia, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 308, 309, 310, with relative weights from 0.5661 to 1.2040 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R00.0 be a principal diagnosis?

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

What is the ICD-9 equivalent of R00.0?

Under the General Equivalence Mappings, tachycardia, unspecified converts to ICD-9-CM 785.0 (tachycardia NOS). 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.