The bradycardia ICD-10 code is R00.1, Bradycardia, unspecified. It’s billable for dates of service from October 1, 2026 through September 30, 2027. You report it once the provider documents a slow heart rate without naming the cause. A named mechanism, such as sick sinus syndrome or heart block, moves the claim to a more specific code.
We wrote this at One O Seven RCM for the coders, billers, and practice managers who handle cardiology claims. It covers the FY2027 rules, the codes that replace R00.1, drug-induced sequencing, newborn and fetal codes, and what R00.1 supports on monitoring and pacemaker claims.
Finding the ICD-10 code for bradycardia takes seconds. Claims break later, on a wrong replacement code, an invalid T code, or an old I49.8 favorite still sitting on the superbill.
| Key takeawaysR00.1 is billable from October 1, 2026 to September 30, 2027, unchanged since ICD-10-CM began.Sinus, sinoatrial, and vagal bradycardia all code to R00.1. No separate sinus bradycardia code exists.Sick sinus syndrome codes to I49.5, AV block to I44, and a sinus pause to I45.5.For a drug adverse effect, R00.1 goes first, then the T code with a fifth or sixth character of 5.ICD-10-CM sets no heart rate cutoff. The provider’s documented diagnosis decides the code.I49.8 became a header on October 1, 2026. Report I49.89 when the record supports it. |
Bradycardia ICD-10 code R00.1 at a glance
R00.1 is a billable symptom code in Chapter 18, inside category R00, Abnormalities of heart beat. You can’t put the R00 header on a claim. R00.1 is the reportable code for a slow heart rate that the provider documents without a named arrhythmia.
R00.1 ICD-10 code card for FY2027 (verified against the FY2027 ICD-10-CM code set)
| Field | Value |
|---|---|
| Code | R00.1 |
| Descriptor | Bradycardia, unspecified |
| Billable | Yes, valid on HIPAA claims |
| Chapter | 18, Symptoms, signs and abnormal clinical and laboratory findings (R00 to R99) |
| Block | R00 to R09, Symptoms and signs involving the circulatory and respiratory systems |
| Category | R00 Abnormalities of heart beat (header, not billable) |
| Inclusion terms | Sinoatrial bradycardia; sinus bradycardia; slow heart beat; vagal bradycardia |
| Excludes1 (at R00.1) | Neonatal bradycardia (P29.12) |
| Excludes1 (at R00) | Abnormalities originating in the perinatal period (P29.1-) |
| Excludes2 (at R00) | Specified arrhythmias (I47 to I49) |
| Use additional code | Adverse effect, if applicable, to identify the drug (T36 to T50, fifth or sixth character 5) |
| FY2027 validity | October 1, 2026 to September 30, 2027 |
| Code history | No change since ICD-10-CM took effect (FY2016) |
| Claim format | R001 |
| MS-DRG as principal diagnosis | 308, 309, or 310 (v44.0) |
| CMS-HCC V28 | None |
| Approximate ICD-9-CM | 427.89 (General Equivalence Mappings) |
R00.1 sits beside R00.0 for tachycardia, R00.2 for palpitations, R00.8, and R00.9. Our guide to the palpitations code R00.2 compares the whole R00 family side by side, including where each code fits on a monitoring claim.
Is R00.1 billable for 2026 and FY2027 dates of service?
Yes. Calendar 2026 spans two code sets, and the date of service picks the set. Your submission date plays no part. January 1 through September 30, 2026 falls under FY2026, while October 1, 2026 onward uses FY2027. Either way, the ICD-10 for bradycardia reads the same: R00.1.
Which code set applies to a 2026 bradycardia claim
| Date of service | Code set | R00.1 status |
|---|---|---|
| January 1 to March 31, 2026 | FY2026 (October 2025 release) | Billable |
| April 1 to September 30, 2026 | FY2026 (April 1 update) | Billable |
| October 1, 2026 onward | FY2027 | Billable, unchanged |
The risk sits in the codes next to R00.1. I49.8 became a header on October 1, 2026, so a superbill favorite carried over from last year fails edits on claims dated October 1 or later. Our cardiology revenue cycle management team rebuilds those favorites lists from the CMS FY2027 ICD-10-CM files before each October 1.
How R00.1 appears on an electronic claim
On the 837 transaction, the decimal drops, so you send the R00.1 diagnosis code as R001. A CMS-1500 carries it in Box 21. Watch for one slip that shows up on EKG lines more than you’d expect: someone keys R00.1 as R01.1, cardiac murmur. Most payers deny that pairing as a diagnosis mismatch.
What R00.1 covers: inclusion terms, Index entries, and sinus bradycardia
An ICD-10 bradycardia lookup ends at the same Tabular entry no matter which wording the provider used. R00.1 covers four inclusion terms plus several Alphabetic Index entries. Sinus bradycardia is one of those inclusion terms, so it has no code of its own.
The four official inclusion terms
The Tabular List puts four terms under R00.1: sinoatrial bradycardia, sinus bradycardia, slow heart beat, and vagal bradycardia. Guideline I.A.11 adds a wrinkle. Inclusion terms aren’t exhaustive, and terms found only in the Index can also lead to the code, so wording outside these four can still land on R00.1.
Category I49 points the same way. Its Excludes2 list sends bradycardia NOS, sinoatrial bradycardia, sinus bradycardia, and vagal bradycardia back to R00.1, which tells you those phrasings don’t belong in the I49 arrhythmia codes.
Index entries and other wording that lead to R00.1
Documentation wording that leads to R00.1 (Alphabetic Index and common chart phrasing)
| Provider wording | Where it comes from | Code |
|---|---|---|
| Bradycardia; sinus, sinoatrial, or vagal bradycardia | Index main term | R00.1 |
| Brachycardia | Index entry (older spelling) | R00.1 |
| Slow heart beat; heart beat, slow | Index | R00.1 |
| Syncope with bradycardia | Index: Syncope, bradycardia | R00.1 (see the symptomatic bradycardia section) |
| “Bradycardic,” “low heart rate,” “HR 48, bradycardic” | Chart phrasing | R00.1 once the provider states it as a diagnosis |
| Bradycardia, neonatal | Index subterm | P29.12 |
| Bradycardia, reflex | Index subterm | G90.09 |
| Bradycardia, tachycardia syndrome | Index subterm | I49.5 |
Read the Index all the way to the subterm. The last three rows leave R00.1 behind, and “reflex” sends you to G90.09, a nervous system code that catches plenty of cardiology coders off guard.
Coders often run a low heart rate ICD-10 search after seeing “bradycardic” in a nurse’s note. Vitals and nursing notes don’t count on their own. You need the provider’s own statement of bradycardia before R00.1 goes on the claim.
Some lookup sites list “AV bradycardia” and “drug-induced bradycardia” as synonyms of R00.1. Neither phrase is a Tabular inclusion term. Drug-induced cases also need a T code, and you’ll find the sequencing in the drug section below.
Is there a separate sinus bradycardia ICD-10 code?
No. The ICD-10 code for sinus bradycardia is R00.1, because sinus bradycardia is an inclusion term under it. Coders keep searching for a separate code because the rhythm sounds specific. The Tabular doesn’t split R00.1 by where in the heart the slow rate starts.
ICD-10 sinus bradycardia questions sometimes hide a different diagnosis. If the provider documents sinus node dysfunction or sick sinus syndrome, you’re coding I49.5 instead. Check any wording in the CDC ICD-10-CM Browser Tool before you code it.
What “unspecified” means in bradycardia, unspecified
In R00.1, “unspecified” means the provider documented a slow heart rate without naming the mechanism behind it. Once the provider names a sinus node, AV conduction, or junctional mechanism, the diagnosis moves to a Chapter 9 code. The ICD-10 code for bradycardia unspecified stays R00.1 until then.
Guideline I.B.18 says unspecified codes have acceptable, even necessary, uses. An unspecified code works like a check engine light: you know something’s off, but not which part. The same guideline warns against ordering tests the patient doesn’t need to reach a more specific code.
ICD-10-CM sets no heart rate threshold for R00.1
No ICD-10-CM rule ties R00.1 to a heart rate. Guideline I.A.19 in the FY2027 ICD-10-CM Official Guidelines bases code assignment on the provider’s diagnostic statement, not on clinical criteria. A pulse of 52 in the vitals isn’t a diagnosis until the provider assesses it as bradycardia.
Clinical sources create the “50 or 60” confusion. The MedlinePlus bradycardia definition describes a resting rate under 60 beats per minute, with 60 to 100 as the normal adult range. NLM’s MeSH bradycardia entry puts the adult rate below 50 in most cases. Neither one is a coding rule.
Some reference tools claim R00.1 requires a rate under 50. It doesn’t. Search the bradycardia, unspecified, ICD-10 rules for a cutoff and you’ll come up empty, because you code from what the provider wrote.
Severe, chronic, and “other” bradycardia: how each one codes
How severity, duration, and “other” wording affect the bradycardia code
| Documentation | Code | Why |
|---|---|---|
| “Severe” or “marked” bradycardia, HR in the 30s, no mechanism named | R00.1 | R00 doesn’t classify by severity. Document the rate and symptoms for medical necessity. |
| “Chronic bradycardia,” still present and addressed | R00.1 | R00.1 has no chronicity axis |
| Bradycardia resolved, no longer treated | No active code for the symptom (see the history section) | R00.1 drops once the problem is gone |
| “Other bradycardia” with a named mechanism such as sinus node dysfunction, AV block, or junctional rhythm | Chapter 9 code (see the comparison section) | The named mechanism moves it out of R00 |
| “Other abnormalities of heart beat” with no bradycardia stated | R00.8 | A different concept from bradycardia |
The ICD-10 code for severe bradycardia is still R00.1. Severity changes what the claim has to show for medical necessity, and it leaves the code alone. Chronic bradycardia and other bradycardia follow the same logic, since no bradycardia ICD-10 rule changes the code for duration or wording until the provider names a mechanism.
The instructional notes that control R00.1
Three notes govern R00.1. An Excludes1 covers neonatal bradycardia, an Excludes2 at category R00 covers specified arrhythmias, and a “use additional code” note covers drug adverse effects. Each one changes what else can, or must, go on the claim.
Excludes1: neonatal bradycardia (P29.12)
Guideline I.A.12.a calls Excludes1 a pure excludes, “NOT CODED HERE.” You don’t report the two codes together. At R00, the note covers abnormalities originating in the perinatal period, so the deciding fact is what the provider documents about where the bradycardia came from. Age alone doesn’t settle it.
The guideline allows both codes when the two conditions are unrelated, and two descriptions of the same slow rate almost never qualify. A claim scrubbing before submission edit that flags R00.1 and P29.12 on one claim lets your team fix the conflict before the payer sees it.
Excludes2 at R00: specified arrhythmias (I47 to I49)
You can code R00.1 with I49.5 only when the record shows the bradycardia as a separate, unexplained finding. Guideline I.A.12.b defines Excludes2 as “not included here,” so both conditions can exist and both codes may appear when appropriate.
Guideline I.B.5 settles most charts. Signs that are a routine part of a disease don’t get separate codes. Once the provider documents sick sinus syndrome, the slow rate is part of that diagnosis, and I49.5 stands alone. If the note leaves the link unclear, query the provider.
Use additional code: drug adverse effects (T36 to T50)
The note tells you to add a T36 to T50 code, with a fifth or sixth character of 5, once a drug taken as prescribed causes the bradycardia. R00.1 goes first for an adverse effect, and the order flips for poisoning. Some references list T50.9X5A. That code doesn’t exist in the FY2027 set.
When to report R00.1 under the FY2027 coding guidelines
Report R00.1 when the provider documents bradycardia and hasn’t confirmed a cause by the end of the encounter. It can be the first-listed diagnosis on an outpatient claim. Once the provider confirms a related diagnosis, such as sick sinus syndrome or heart block, that code replaces it.
A symptom code is correct until the provider confirms a cause
Guideline I.B.4 accepts symptom codes when the provider hasn’t established a related definitive diagnosis, and Guideline IV.D repeats the rule for outpatient care. R00.1 can lead the claim when bradycardia is the reason for the visit. Outpatient coders call that first-listed; principal diagnosis is the inpatient term.
Picture a referral that reads “bradycardia, HR 46,” followed by a normal workup at the visit. The cardiologist finds nothing more specific. That encounter stays at R00.1, and your team doesn’t need to hunt for a better code.
Outpatient visits: “rule out” and “possible” diagnoses still code to R00.1
Guideline IV.H tells outpatient coders not to code diagnoses documented as probable, suspected, questionable, rule out, or working diagnosis. Uncertain wording stays off the claim. You code to the highest degree of certainty for that encounter instead.
Worked example: an outpatient bradycardia visit
| Note says | First-listed code |
|---|---|
| “Sinus bradycardia, HR 48 on EKG. Rule out sick sinus syndrome. Holter ordered.” | R00.1, with no I49.5 until the provider confirms it |
Inpatient rules differ. Section II.H lets facility coders report an uncertain diagnosis documented at discharge as if the provider had established it. Most compliance teams still apply the outpatient rules to physician claims for hospital visits, so confirm your own policy.
Once a Holter result or a signed EKG read names the rhythm, the code can move. Our guide to EKG billing with 93000 covers how that interpretation line bills and which diagnoses it carries.
Symptomatic bradycardia ICD-10 coding
There’s no separate code for symptomatic bradycardia. The ICD-10 code for symptomatic bradycardia is R00.1 unless the provider names a mechanism. In the Alphabetic Index, “Syncope, bradycardia” points to R00.1, which shows how the classification treats that pairing.
Practices differ on adding R55 or R42 as separate codes. Follow the Index first, then check AHA Coding Clinic and your compliance policy before anyone adds them out of habit.
Document the symptoms anyway. Medical necessity for the EKG, Holter, or pacemaker evaluation rests on them, and the 2018 ACC/AHA/HRS bradycardia guideline stresses correlating symptoms with the slow rhythm.
Asymptomatic, athletic, and sleep-related bradycardia
A slow rate the provider documents as a normal finding, such as a trained athlete at rest or a rate during sleep, gives you nothing to code. If the provider diagnoses asymptomatic bradycardia and addresses it at the visit, R00.1 applies.
The coverage catch comes later. Medicare’s pacemaker policy lists asymptomatic sinus bradycardia as non-covered, and the 2018 guideline says bradycardia during sleep isn’t a pacing indication by itself. Read the NCD 20.8.3 pacemaker rules before anyone schedules the implant.
Take a Friday EKG read: “sinus brady, HR 49, asymptomatic.” Someone on the team reaches for I49.5 because it looks more complete. Nothing in that read names sinus node dysfunction, so R00.1 is the code, and I49.5 on that claim turns into an audit finding.
If your team keeps coding R00.1 when the note supports I49.5, or the other way around, the pattern shows up in denials and audits. We can run a cardiology coding audit on your recent bradycardia claims and show you where the documentation and the code split.
R00.1 versus specific bradyarrhythmia codes
R00.1 describes a slow rate without a mechanism. Once the provider names the mechanism, a specific code replaces it, and the bradycardia ICD-10 choice moves out of Chapter 18. Use the table below to match the documented mechanism to its code.
Category R00 carries an Excludes2 for I47 to I49, which permits pairing R00.1 with those codes. Guideline I.B.5 still bars coding a symptom that comes with the confirmed disease. That’s why R00.1 drops when sick sinus syndrome or complete heart block explains the slow rate.
Which code replaces R00.1 once the provider names a mechanism (FY2027)
| Provider documents | Code | Note |
|---|---|---|
| Bradycardia, no mechanism named | R00.1 | Symptom code |
| Sick sinus syndrome, tachy-brady syndrome, sinus node dysfunction | I49.5 | Bradycardia is integral; don’t add R00.1 |
| Sinus pause, sinus arrest, SA block | I45.5 | Index: Sinus, pause and Sinus, arrest |
| First-degree AV block | I44.0 | PR prolongation without dropped beats |
| Second-degree AV block, Mobitz I or II | I44.1 | One code covers both types |
| Complete (third-degree) heart block | I44.2 | Pacemaker indication under NCD 20.8.3 when symptomatic |
| AV block, degree not stated | I44.30 | Not on WPS A57476; query for the degree |
| Congenital heart block | Q24.6 | Chapter 17 code |
| Junctional or nodal rhythm | I49.89 | FY2027 code; I49.8 is now a header |
Sick sinus syndrome and tachy-brady syndrome: I49.5
The sick sinus syndrome ICD-10 code is I49.5. A sinus node dysfunction ICD-10 lookup lands on the same code, and so does an SSS ICD-10 search. Use it once the provider documents the syndrome, with the strips or monitor findings that support it.
The Index sends bradycardia-tachycardia syndrome to I49.5 too. A tachy-brady syndrome ICD-10 claim doesn’t need a separate tachycardia code, and R00.1 stays off. An ICD-10 sick sinus syndrome claim also carries risk-adjustment weight, since I49.5 shares a category with atrial fibrillation, as our guide to HCC 238 for arrhythmia codes explains.
Sinus pause, sinus arrest, and SA block: I45.5
The sinus pause ICD-10 code is I45.5, Other specified heart block. In the Index, both “Sinus, pause” and “Sinus, arrest” lead there, so a sinus arrest ICD-10 claim uses the same code. Several coding sites place sinus pause under I49.5, and the Index doesn’t support that.
Pause length doesn’t change the code. A 3.2-second pause on a Holter with no sick sinus diagnosis stays at I45.5. If the provider later diagnoses sick sinus syndrome, I49.5 replaces it and the pause becomes part of the syndrome.
AV block and complete heart block: I44 codes
AV block ICD-10 coding turns on the degree the provider documents. First-degree block is I44.0, second-degree block of either Mobitz type is I44.1, and the complete heart block ICD-10 code is I44.2. Congenital heart block moves to Q24.6.
Watch the unspecified code. WPS billing article A57476 lists I44.0, I44.1, I44.2, and I44.39 for Holter monitoring, but it doesn’t list I44.30, unspecified AV block. In WPS states, a Holter claim with I44.30 has no covered-list match, so ask the provider to document the degree.
Junctional bradycardia ICD-10: I49.89 or R00.1
The Bradycardia main term in the Index has no junctional subterm. A note that says only “junctional bradycardia” defaults to R00.1. Once the provider documents a junctional rhythm or nodal rhythm, the junctional rhythm ICD-10 code for FY2027 dates of service is I49.89.
Search results and AI tools still give I49.8. That code turned into a non-billable header on October 1, 2026, when the FY2027 update split it into I49.81, I49.82, and I49.89. WPS made the same swap on its Holter coverage list, as our note on the I49.8 change on Holter claims explains.
If the provider documents a slow rate and a junctional rhythm disorder as separate findings, the Excludes2 at R00 allows R00.1 and I49.89 together. Confirm the FY2027 Index entry for “Rhythm, nodal” in your encoder before you lock in a charge template.
Sinus bradycardia with sinus arrhythmia
The Index sends sinus arrhythmia to the I49.8 subcategory, so the sinus arrhythmia ICD-10 code for FY2027 dates is I49.89. Sinus bradycardia stays at R00.1. If the provider documents both, you report both, since the Excludes2 at R00 allows the pair.
R00.1 versus R94.31
R94.31 is the code for an abnormal electrocardiogram. Use it when the record shows an abnormal tracing and the provider hasn’t stated a condition. Once the provider states bradycardia, R00.1 is the more specific choice, and the R94.31 diagnosis code drops for that same finding. Report both only if the EKG shows a separate abnormality.
Drug-induced bradycardia ICD-10: adverse effect versus poisoning
The coding turns on one question: did the patient take the drug as prescribed? If yes, it’s an adverse effect, and R00.1 goes first. A wrong drug, a wrong dose, or an overdose makes it a poisoning, and the T code goes first.
Guideline I.C.19.e.5.(a) covers adverse effects: sequence the effect first, then the T code with a fifth or sixth character of 5. Poisoning falls under I.C.19.e.5.(b), which includes errors in prescription or administration and drugs taken with alcohol. The T code leads there, and unknown intent defaults to accidental.
Adverse effect and accidental poisoning codes for common bradycardia drugs (FY2027, initial encounter)
| Drug class | Adverse effect | Accidental poisoning |
|---|---|---|
| Beta-blockers (metoprolol, atenolol) | T44.7X5A | T44.7X1A |
| Calcium channel blockers (diltiazem, verapamil) | T46.1X5A | T46.1X1A |
| Digoxin and other cardiac glycosides | T46.0X5A | T46.0X1A |
| Other antidysrhythmics (amiodarone) | T46.2X5A | T46.2X1A |
| Drug not specified | T50.905A | Report the drug once the provider names it |
| Two codes AI tools get wrongT50.9X5A doesn’t exist. Use T50.905A for an unspecified drug.T45.1X5A is the adverse effect of antineoplastic drugs. Beta-blocker bradycardia takes T44.7X5A. |
The seventh character tracks the encounter: A for active treatment, D for a subsequent encounter, and S for sequela. Watch the phrase “digoxin toxicity.” It doesn’t settle the question by itself, so check whether the patient took the drug as prescribed and query the provider if the note doesn’t say.
Medicare’s pacemaker policy lists medication-caused bradycardia as a non-covered indication because the cause is reversible. Your T code documents that cause, and the pacemaker coverage section below shows where that affects an implant claim.
Neonatal and fetal bradycardia ICD-10 codes
Bradycardia around birth can land on three different records. The newborn’s chart gets P29.12 for neonatal bradycardia. On the mother’s record, you use O36.83- during antepartum care and O76 during labor and delivery. A newborn affected by a fetal heart rate abnormality gets a P03.81- code.
Neonatal and fetal heart rate codes by record
| Whose record | Situation | Code |
|---|---|---|
| Newborn | Bradycardia in the newborn | P29.12 |
| Mother, antepartum | Care for a fetal heart rate abnormality | O36.83- (sixth character for trimester, seventh for the fetus, such as O36.8330) |
| Mother, labor and delivery | Fetal heart rate abnormality during labor | O76 |
| Newborn | Affected by a fetal heart rate abnormality | P03.810, P03.811, or P03.819, by time of onset |
Guideline I.C.16.a keeps Chapter 16 codes off the maternal record. The same guideline lets a perinatal condition keep its P code at any age while the condition continues, so a toddler with ongoing perinatal bradycardia can still carry P29.12. R00.1 and P29.12 never share a claim.
The maternal pair trips up OB coders. O76 belongs to the labor and delivery encounter. O36.83- covers antepartum visits where the abnormality changes how the provider manages the pregnancy.
History of bradycardia and pacemaker status codes
Stop reporting R00.1 once the bradycardia has resolved and the provider no longer treats it. A symptom doesn’t carry forward the way a chronic disease does. Code what the provider addresses at this visit.
Z86.79, personal history of other diseases of the circulatory system, fits resolved Chapter 9 conditions such as sick sinus syndrome or AV block. R00.1 is a Chapter 18 symptom, so Z86.79 isn’t its history code. Check “History, personal” in the Index before you report any history code for a resolved symptom.
Z95.0, presence of cardiac pacemaker, adds status. Code the underlying condition too when the provider documents it as current. Encounters for checking and testing the pulse generator use Z45.010. Our guide to remote pacemaker interrogation billing shows Novitas listing both Z95.0 and R00.1 for device monitoring.
Documentation-to-code scenarios and provider checklist
Start with the words. Getting bradycardia ICD-10 coding right means reading the note the way an auditor would, line by line. Each row below pairs a chart phrase your coders will recognize with the code it supports.
Documentation-to-code scenarios for bradycardia (FY2027)
| Note says | Codes | Why |
|---|---|---|
| “Bradycardia due to metoprolol, dose reduced” | R00.1, T44.7X5A | Adverse effect: the effect goes first |
| “Took a double dose of diltiazem by mistake, HR 38” | T46.1X1A, R00.1 | Poisoning: the T code goes first |
| “Tachy-brady syndrome, plan pacemaker” | I49.5 | Bradycardia is integral to the syndrome |
| “Complete heart block, ventricular escape” | I44.2 | Mechanism named |
| “3.2-second sinus pause on Holter, no SSS” | I45.5 | Index: Sinus, pause |
| “Junctional rhythm at 42 bpm” | I49.89 | FY2027 code for a nodal rhythm |
| “Newborn, day 2, recurrent bradycardia” | P29.12 | Newborn record |
| EKG read: “sinus bradycardia, rate 52” | R00.1 on the interpretation claim | Guideline IV.K: code the confirmed diagnosis in the read |
The last row catches plenty of billing teams. Guideline IV.K says that when a physician has interpreted a diagnostic test and the final report is available, you code the confirmed diagnosis documented in the interpretation. For that claim, you code from the read.
Hand this checklist to your providers. Each item closes a gap that sends bradycardia claims back for queries, denials, or recoding.
- Mechanism: sinus, junctional, pause, or AV block with its degree
- Symptoms, and whether the provider links them to the slow rate
- Cause: the drug name, and whether the patient took it as prescribed
- Reversibility, which drives pacemaker coverage under NCD 20.8.3
- Rate, plus the strip or monitor it came from
- Plan: watch, adjust medication, monitor, or refer for pacing
CPT services R00.1 supports and Medicare coverage limits
R00.1 supports most diagnostic cardiac testing, and it falls short on pacemaker implants. A bradycardia ICD-10 code that names only the symptom can justify an EKG or Holter, while Medicare’s pacemaker policy wants the mechanism. Our cardiology CPT code hub covers each test in depth.
How R00.1 lines up with common cardiology CPT services
| Service | CPT | R00.1 status | Our guide |
|---|---|---|---|
| EKG | 93000 | Supports a diagnostic EKG; screening EKGs follow separate rules | CPT 93000 EKG coverage |
| Holter, up to 48 hours | 93224 to 93227 | Listed in WPS article A57476, Groups 1 to 3 | Holter monitor billing |
| Event monitor | 93268 | Listed in Novitas billing articles | event monitor coverage lists |
| Remote pacemaker check | 93294 | Listed in Novitas article A56602 | See the history section above |
| Pacemaker implant | 33208 | Doesn’t state the NCD 20.8.3 indication on its own | dual-chamber pacemaker billing |
Medicare’s NCD 20.8.3 for permanent pacemakers covers implants for documented, non-reversible, symptomatic bradycardia due to sinus node dysfunction or second- or third-degree AV block. R00.1 names neither cause. Lead the implant claim with I49.5, I44.1, or I44.2, and leave R00.1 off once you’ve coded the mechanism.
Coverage and coding run on separate rulebooks. The NCD ties bradycardia symptoms to a heart rate under 60 beats per minute, while ICD-10-CM sets no threshold at all. A note can support R00.1 and still fall short of the coverage rule.
Covered diagnosis lists differ by MAC. The WPS billing article A57476 lists R00.1 for Holter monitoring, and your contractor’s article may carry a different list. Our primer on LCDs and billing articles explains how to find yours.
Many Medicare Advantage and commercial plans require prior authorization for pacemaker implants and extended monitoring. Our eligibility and prior authorization team confirms the requirements before the procedure goes on the schedule, so a missing authorization doesn’t sink a clean code.
MS-DRG and HCC impact of R00.1 versus specific codes
On the inpatient side, specificity seldom changes the DRG family. R00.1 and I49.5 both group to MS-DRG 308, 309, or 310 as principal diagnosis under the FY2027 grouper, with CC and MCC status setting the level.
Risk adjustment follows its own rules. R00.1 carries no CMS-HCC V28 category. Under the 2027 CMS risk adjustment mappings, I49.5 and I44.2 map to HCC 238, Specified Heart Arrhythmias. Medicare Advantage plans need the condition documented and addressed at a face-to-face encounter each calendar year.
HCC value never justifies a code the record doesn’t support. A coding specificity review checks whether your providers document the mechanism once they’ve found one. Our cardiology billing specialists apply the same check to daily claims, so specificity doesn’t depend on who’s coding that morning.
Why R00.1 claims get denied and how to fix them
Most bradycardia ICD-10 denials trace back to four habits: an outdated code, a wrong T code, reversed sequencing, or a symptom code where the payer wanted a mechanism. Each one has a fix at the coding step.
Common R00.1 claim problems and fixes
| Problem | What happens | Fix | Our guide |
|---|---|---|---|
| I49.8 on a date of service October 1, 2026 or later | Front-end rejection: non-billable header | I49.89 if the record supports it | |
| T50.9X5A on the claim | Rejected as an invalid code | T50.905A | |
| T code first-listed for an adverse effect | Sequencing error | R00.1 first, then the T code | |
| R00.1 and P29.12 on one claim | Excludes1 edit | One code only, by record type | |
| R00.1 on a pacemaker claim with no SND or AV block code | CO-11 or CO-50 denial | Code the documented mechanism | CO-11 diagnosis mismatch denials |
| Asymptomatic or reversible bradycardia on a pacemaker claim | CO-50 with N115 (NCD 20.8.3) | Get a signed ABN before the service and append GA; never change the diagnosis | CO-50 medical necessity denials |
| I44.30 on a WPS Holter claim | No covered-list match | Ask the provider to document the AV block degree |
Front-end rejections never reach a remittance, so track them apart from denials. A rejected I49.8 or T50.9X5A claim sits in the clearinghouse queue until someone corrects and resubmits it. Our front-end edit checks stop those codes before the claim leaves your system.
If the same bradycardia denials come back every month, our denial management team traces them to the coding step that produced them and fixes the workflow there.
Bradycardia ICD-10 FAQs
What is the ICD-10 code for bradycardia?
R00.1, Bradycardia, unspecified, is the ICD-10 code for bradycardia when the provider hasn’t named a mechanism. The same code covers all 2026 dates of service, because the FY2026 and FY2027 code sets both carry R00.1 with no change. A named cause such as sick sinus syndrome or heart block moves you to a specific code.
Is R00.1 billable in 2026?
Yes. R00.1 is billable for all 2026 dates of service, and you report it as R001 on electronic claims. Claims dated October 1, 2026 or later use the FY2027 code set, where the ICD-10 for bradycardia hasn’t changed. Check that the codes around it are current too, such as I49.89 in place of I49.8.
What is the ICD-10 code for junctional bradycardia?
Code R00.1 when the provider names only a slow rate. Once the provider documents a junctional or nodal rhythm, the FY2027 code is I49.89. I49.8 turned into a non-billable header on October 1, 2026, so answers that still give I49.8 will fail claim edits for current dates of service.
What is the ICD-10 code for sinus pause?
I45.5, Other specified heart block. The Alphabetic Index sends both sinus pause and sinus arrest to I45.5, even though some references list I49.5. If the provider later diagnoses sick sinus syndrome, I49.5 replaces I45.5, and the pause becomes part of that diagnosis.
Is bradycardia an HCC?
R00.1 isn’t. The symptom code carries no CMS-HCC V28 category. Sick sinus syndrome (I49.5) and complete heart block (I44.2) map to HCC 238, Specified Heart Arrhythmias, so the documented mechanism carries weight in Medicare Advantage risk scores. The provider still has to document and address the condition each calendar year.
Can R00.1 be a principal diagnosis?
Yes. R00.1 can serve as the principal diagnosis when the workup doesn’t establish a definitive cause. It groups to MS-DRG 308, 309, or 310, with CC and MCC status setting the level. Outpatient claims use the term first-listed diagnosis for the same role.
What was the ICD-9 code for bradycardia?
Under the General Equivalence Mappings, R00.1 corresponds to ICD-9-CM 427.89, other specified cardiac dysrhythmias. Neonatal bradycardia was 779.81. The mappings are approximate, so use them for historical data work and keep current claims on ICD-10-CM.
Can bradycardia be coded when a patient has a pacemaker?
Yes, when the provider documents bradycardia as a current, addressed problem. Add Z95.0 to show the pacemaker status. If the device controls the rate and the provider doesn’t address bradycardia at the visit, report Z95.0 with the conduction diagnosis the provider documents and leave R00.1 off. Suspected device malfunction needs its own complication code.
Getting bradycardia claims paid the first time
Clean bradycardia ICD-10 claims come down to three habits. Name the mechanism once the provider has found one. Code the cause if a drug or a newborn condition explains the slow rate, and check the payer’s covered list before the test goes out the door.
If your team wants that discipline on each cardiology claim without adding staff, One O Seven RCM’s full-service RCM team codes, scrubs, and follows up on those claims for you. Bring the bradycardia denials you’re seeing when you schedule a consultation.
Sources
- CMS: ICD-10 codes and FY2027 files
- CDC ICD-10-CM Browser Tool
- FY2027 ICD-10-CM Official Guidelines for Coding and Reporting
- MedlinePlus (NIH/NLM): Bradycardia
- NLM MeSH: Bradycardia
- 2018 ACC/AHA/HRS Guideline on Bradycardia and Cardiac Conduction Delay
- CMS NCD 20.8.3: Single Chamber and Dual Chamber Permanent Cardiac Pacemakers
- CMS MCD: WPS Billing and Coding Article A57476
- CMS: Medicare Advantage Risk Adjustment
