CMS modified NCD 104 governing diagnostic endocardial electrical stimulation (EES), also called programmed electrical stimulation of the heart, effective March 7, 2026. Here's what billing teams need to know.
The Centers for Medicare & Medicaid Services updated NCD 104 — the National Coverage Determination governing Medicare's EES coverage policy — as of the effective date of March 7, 2026. This policy covers diagnostic procedures used to study cardiac arrhythmias and conduction abnormalities in patients with severe cardiac conditions. The policy does not list specific CPT or HCPCS codes, which creates a real challenge for charge capture and claim submission that your billing team needs to address now.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS (Medicare) |
| Policy | Diagnostic Endocardial Electrical Stimulation (Pacing) |
| Policy Code | NCD 104 |
| Change Type | Modified |
| Effective Date | 2026-03-07 |
| Impact Level | Medium |
| Specialties Affected | Electrophysiology, Cardiology, Interventional Cardiology, Outpatient Hospital Billing |
| Key Action | Confirm your charge capture aligns with updated medical necessity criteria and verify code assignment with your MAC before billing EES procedures |
CMS Endocardial Electrical Stimulation Coverage Criteria and Medical Necessity Requirements 2026
The CMS EES coverage policy is narrow by design. Medicare covers diagnostic endocardial electrical stimulation only for patients with severe cardiac arrhythmias. That's the threshold — and it matters, because "severe" is doing a lot of work in that sentence.
The policy describes EES as a diagnostic procedure used to investigate the mechanisms, site of origin, and pathways of cardiac arrhythmias. It's also used to select the right treatment approach and to identify patients at risk of sudden arrhythmic death. The principal use is in the diagnosis and treatment of sustained ventricular tachycardia.
The Centers for Medicare & Medicaid Services also recognizes EES for diagnosis and management of other complex arrhythmias, conduction defects, and post-cardiac arrest evaluation. These secondary indications are covered — but they have to be documented as complex. Routine arrhythmia workups don't meet the bar.
Medical necessity documentation must support the severity and complexity of the arrhythmia being investigated. If your clinical notes say "palpitations" or "mild arrhythmia," expect a claim denial. Your physicians need to clearly document why EES — an invasive, catheter-based procedure — is the appropriate diagnostic step, not just a convenient one.
The procedure itself requires intracardiac electrode catheters, intracardiac and extracardiac recordings, and a stimulator device. Between two and six multipolar electrode catheters are inserted percutaneously — usually through the femoral veins — and advanced to the heart under fluoroscopic control. Other venous or arterial routes may be used as well. An intracardiac His bundle cardiogram is typically obtained during EES, along with conventional electrocardiograms.
Here's a billing point that trips up a lot of teams: Medicare will not recognize a separate charge for the His bundle cardiogram. It's bundled into the EES procedure. If your charge capture is generating a separate line item for the His bundle study, remove it. That charge will deny.
This coverage policy applies across benefit categories — including diagnostic services in outpatient hospital settings, diagnostic tests, and physicians' services. So whether you're billing the facility side or the professional side, NCD 104 governs the coverage.
The policy does not mention prior authorization requirements at the NCD level. That said, your Medicare Administrative Contractor may have additional local coverage determination rules that layer on top. Check with your MAC before assuming prior authorization isn't needed for your region.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Sustained ventricular tachycardia — diagnosis and treatment | Covered | Not specified in NCD 104 | Principal use per CMS; strong medical necessity documentation required |
| Identifying patients at risk of sudden arrhythmic death | Covered | Not specified in NCD 104 | Must document risk factors and clinical rationale |
| Complex arrhythmias — diagnosis and management | Covered | Not specified in NCD 104 | Must document complexity; routine arrhythmias do not qualify |
| Conduction defects — diagnosis and management | Covered | Not specified in NCD 104 | Clinical notes must support EES as appropriate diagnostic step |
| Post-cardiac arrest evaluation | Covered | Not specified in NCD 104 | Document arrest history and clinical indication clearly |
| His bundle cardiogram (separately billed) | Not Covered | Not specified in NCD 104 | Bundled into EES; no separate reimbursement recognized by Medicare |
CMS Endocardial Electrical Stimulation Billing Guidelines and Action Items 2026
The absence of specific CPT or HCPCS codes in NCD 104 is the biggest practical problem here. It doesn't mean you can't bill — it means you need to do more homework before March 7, 2026 to make sure your coding is defensible.
| # | Action Item |
|---|---|
| 1 | Contact your MAC immediately. Because NCD 104 does not list specific CPT or HCPCS codes, your Medicare Administrative Contractor is your next stop. Ask which codes your MAC recognizes for diagnostic endocardial electrical stimulation billing in your region. Some MACs have issued local coverage determinations that specify codes — get that documentation in hand before the effective date. |
| 2 | Audit your charge capture for the His bundle cardiogram. If your team has been billing a separate charge for the His bundle cardiogram during EES procedures, stop. NCD 104 explicitly states that no separate charge will be recognized. Pull the last 90 days of EES claims and look for any unbundled His bundle line items. If you find them, assess whether you need to file corrected claims. |
| 3 | Tighten your medical necessity documentation requirements. Work with your cardiology and electrophysiology medical directors to set clear documentation standards before March 7, 2026. The operative word in this coverage policy is "severe." Clinical notes must document severe cardiac arrhythmias — not just arrhythmias. A diagnosis of sustained ventricular tachycardia, complex arrhythmias requiring EES-level investigation, post-arrest evaluation, or documented risk of sudden arrhythmic death should all be explicitly stated in the medical record. |
| 4 | Verify benefit category assignment on your claims. NCD 104 spans multiple benefit categories: outpatient hospital diagnostic services, other diagnostic tests, and physicians' services. Make sure your facility and professional claims correctly reflect the benefit category. Misassignment is a clean path to a claim denial. |
| 5 | Cross-reference NCD 20.16 for His bundle cardiogram policy. CMS references Section 20.16 in NCD 104 for the His bundle cardiogram bundling rule. Pull that section and make sure your billing guidelines reflect the same bundling logic. If there's any ambiguity in how your team interprets the overlap between these two policies, loop in your compliance officer before the effective date. |
| 6 | Train your coding team on the procedure requirements. EES requires intracardiac electrode catheters, intracardiac and extracardiac recordings, and a stimulator device. Your coders need to confirm these elements are documented in the procedure note before submitting an EES claim. Missing documentation of required components is grounds for denial or post-payment audit. |
| 7 | Flag EES claims for pre-submission review until code clarity is confirmed. Until your MAC confirms which codes to use, route all EES claims through a billing supervisor or coder with electrophysiology experience for pre-submission review. One denied claim is manageable. A pattern of denials while you're figuring out coding creates a compliance exposure you don't want. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Diagnostic Endocardial Electrical Stimulation Under NCD 104
This is where diagnostic endocardial electrical stimulation billing gets frustrating. NCD 104 does not specify CPT, HCPCS, or ICD-10 codes. That's not an oversight in this article — it's the actual state of the policy document.
Covered CPT Codes (When Medical Necessity Criteria Are Met)
| Code | Type | Description |
|---|---|---|
| Not specified | — | NCD 104 does not list specific CPT or HCPCS codes. Contact your MAC for regional guidance on applicable codes. |
Key ICD-10-CM Diagnosis Codes
| Code | Description |
|---|---|
| Not specified | NCD 104 does not list specific ICD-10-CM diagnosis codes. Document the underlying arrhythmia or conduction defect diagnosis from your physician's clinical record. |
The real answer here is that your MAC is the authoritative source for which codes apply in your jurisdiction. Electrophysiology procedures like EES typically map to established CPT codes in the cardiac catheterization and electrophysiology range — but because NCD 104 doesn't name them, billing those codes under this NCD requires MAC confirmation. Don't guess. The reimbursement risk isn't worth it.
If you're billing EES in an outpatient hospital setting, work with your facility coder and compliance officer together. Facility and professional fee billing for invasive cardiac diagnostic procedures carry audit risk, especially when the underlying NCD lacks specific code guidance.
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