2026 ICD-10-CM Diagnosis Code R00.0

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Clinical Information

• 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.

MS-DRG Mapping for ICD-10-CM Code R00.0

Diagnosis-Related Groups (DRGs) are used to classify hospital cases for billing and healthcare management. They help standardize how hospitals and other providers are reimbursed for inpatient care. Patients are grouped based on their principal diagnosis into broader categories called Major Diagnostic Categories (MDCs).

Once assigned to a DRG, the hospital receives a set payment for the patient’s care, regardless of the actual services provided. This fixed rate is intended to cover the typical cost of treating patients within that group. The payment amount depends on the DRG's relative weight, which reflects the expected complexity and cost of care based on the severity of the patient’s condition.

Diagnostic related groups encourage healthcare providers to focus on quality and efficiency in patient care while managing costs effectively. The diagnosis code is present in the following groups for version MS-DRG V43.0 applicable from 10/01/2025 through 09/30/2026.

Convert R00.0 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Patient Education

Arrhythmia

What is an 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.

• When your heart beats faster than normal, it's called tachycardia.
• When your heart beats too slowly, it's called bradycardia.
• When the signal to beat comes too early, it's called a premature or extra heartbeat. It may feel like your heart skipped a beat.

There are many types of arrhythmias. Arrhythmias may affect the upper or lower chamber of your heart. The most common type of arrhythmia is atrial fibrillation, which causes an irregular and fast heartbeat.

Some arrhythmias are harmless, such as when your heart rate speeds up during exercise and slows down when you sleep. But if you have a frequent irregular rhythm, it may mean your heart isn't pumping enough blood into your body. Getting treatment and following a heart-healthy lifestyle can help control arrhythmias. It may also help prevent heart damage that can trigger some heart arrhythmias.

What causes an arrhythmia?

Many factors can affect your heart's rhythm, such as having had a heart attack, smoking, congenital heart defects, and stress. Other factors that could increase your risk for some types of arrhythmias could include if you:

• Have a family history of arrhythmias.
• Have certain health conditions, which can include heart and blood vessel diseases, lung diseases, kidney diseases, obesity, and sleep apnea.
• Are an older adult.
• Have had recent surgery for your heart, lungs, or throat.
• Take certain medicines for other health conditions.
• Use illegal drugs.

If you have risk factors, some situations that make your heart work harder, raise your blood pressure, or cause strong emotional stress may trigger an arrhythmia.

What are the symptoms of an arrhythmia?

You may not have any noticeable symptoms of an arrhythmia. Your provider may find an arrhythmia during your routine checkup. Symptoms of an arrhythmia can include:

• Fast or slow heartbeat
• Skipping, fluttering, or pounding heartbeats
• Chest pain or discomfort
• Dizziness or fainting
• Shortness of breath
• Sweating
• Tiredness or weakness

Seek emergency medical care if you have chest pain, shortness of breath, or think you are having a heart attack.

How is an arrhythmia diagnosed?

To find out if you have an arrhythmia, your health care provider may order an electrocardiogram (EKG). This test records your heart's electrical activity and is the most common for finding an arrhythmia. Your provider may also:

• Ask about your medical history, including your symptoms and lifestyle habits.
• Do a physical exam, which includes checking your heartbeat and pulse.
• Order blood tests and other heart tests.
• Check your legs or feet for swelling.
• Look for signs of other health conditions that could cause an arrythmia, such as thyroid disease.

What are the treatments for an arrhythmia?

Treatment may include medicines, an implantable cardioverter-defibrillator (ICD) or pacemaker, or sometimes surgery. Your provider may also recommend avoiding activities that may trigger your arrhythmia.

The goal of treatment is to restore a normal heart rhythm. If not treated, arrhythmias can damage your heart, brain, and other organs and could be life-threatening.

Can arrhythmias be prevented?

To help prevent an arrhythmia, your provider may suggest that you make heart-healthy lifestyle changes and treat health conditions that may cause arrhythmias.

NIH: National Heart, Lung, and Blood Institute

Code History

• FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
• FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
• FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
• FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
• FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
• FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
• FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
• FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
• FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
• FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
• FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.