Electrophysiology (EP) studies are highly detailed diagnostic procedures used to evaluate arrhythmias, conduction disorders, syncope, wide-complex tachycardia, pre-excitation, and other rhythm abnormalities. Because EP studies involve multiple catheters, multiple chambers, optional stimulation protocols, mapping, and add-on services, the CPT structure for 93600–93662 is one of the most complex areas in cardiovascular coding.
Accurate billing depends on understanding the difference between basic vs comprehensive EP studies, what the base codes include, when add-on codes apply, what documentation payers expect, and how to avoid unbundling errors and modifier misuse. This guide provides a full, highly practical explanation for clinicians and coders with no sales language—only value and clarity.
Understanding EP Study Structure Before Coding
EP studies typically include:
- Vascular access
- Multipolar catheter placement
- Baseline intracardiac electrograms
- Programmed stimulation from various chambers
- Arrhythmia induction attempts
- Response evaluation
- Mapping (when performed)
- Optional left atrial or left ventricular access
- Optional drug infusion testing
- Optional ablation (not part of EP study codes)
These elements build the foundation of the CPT range 93600–93662, which depends on:
- Number of chambers studied
- Whether pacing/stimulation occurred
- Whether left atrial or LV access occurred
- Whether 3D mapping or intracardiac echo (ICE) was used
- Whether drug testing was performed
- Whether the procedure was strictly diagnostic or led into ablation
CPT Code Overview (93600–93662)
Below is a practical breakdown of each code category.
Intracardiac Electrogram and Stimulation Codes
These codes represent targeted pacing or electrogram acquisition without a full comprehensive EP study.
93600 – Bundle of His recording only
93602 – Atrial recording
93603 – Ventricular recording
93610 – Intra-atrial pacing
93612 – Intraventricular pacing
93618 – Induction of arrhythmia by electrical stimulation
These are used when a full EP study is not performed, such as during device checks, targeted stimulation, or limited diagnostic needs.
Comprehensive EP Studies (Major Codes)
These codes represent complete studies with multipolar catheters and multiple chambers.
93619 – Comprehensive EP study (atrial + His + ventricular) without left atrial pacing/recording
93620 – Comprehensive EP study with left atrial pacing/recording
93653 – Comprehensive EP study with SVT ablation
93654 – Comprehensive EP study with VT ablation
93656 – Comprehensive EP study with atrial fibrillation ablation
Important:
When ablation is performed (93653–93656), the comprehensive diagnostic EP study is bundled and cannot be billed separately.
Add-on Codes Commonly Used
These may be billed only in addition to a primary code.
93621 – Left ventricular pacing & recording
93622 – Left atrial mapping
93623 – Drug infusion for arrhythmia induction
93662 – Intracardiac echocardiography (ICE)
93613 – 3D mapping
93609 – Additional mapping (older code; usage depends on payer)
Add-on codes require clear documentation of:
- Purpose
- Chamber
- Technique
- Interpretation
What’s Included in Base EP Study Codes
Failing to understand included services leads to many denials.
Comprehensive EP study codes include:
- Catheter placement
- Fluoroscopy
- Electrogram interpretation
- Baseline pacing
- Induction attempts
- His bundle recording
- Atrial and ventricular pacing/recording (depending on code)
Because these components are bundled, separate billing for:
- Fluoroscopy
- Vascular access
- Catheter placements
- Standard intracardiac electrograms
- Standard stimulation
…is not allowed.
When Add-On Codes Are Appropriate
Coders must know when add-ons are valid versus bundled.
Correct Examples
- 93620 + 93621 when LV pacing/recording is performed
- 93620 + 93613 for 3D mapping for complex arrhythmia evaluation
- 93620 + 93623 if isoproterenol or dobutamine is infused to induce arrhythmia
- 93656 + 93662 for ICE during AF ablation
Incorrect Examples
- Billing 93621 or 93622 without documentation of mapping or LV involvement
- Billing 93623 when medications were used for sedation, not arrhythmia
- Billing mapping (93613) when documentation says “mapping performed to guide ablation”—this is bundled into ablation
Documentation Requirements for EP Studies
Physicians must document:
Indication
Examples:
- SVT evaluation
- VT with structural heart disease
- Syncope with suspected conduction disease
- Pre-ablation diagnostic study
- Wide-complex tachycardia differentiation
Catheter Placement Details
- Number of catheters
- Location: RA, RV, His, coronary sinus, LV
- Mapping and pacing sites
Stimulation Protocol
- Baseline measurements
- Number of pacing trains
- Frequency/duration
- Arrhythmia induction attempts
- Clinical vs non-clinical arrhythmia induction
Mapping Documentation
Should include:
- Chamber
- Rationale
- Findings
- Map interpretations
Drug Testing
- Name of agent (e.g., isoproterenol)
- Doses & timeline
- Purpose (arrhythmia induction only)
Final Interpretation
- Mechanism of arrhythmia
- Conduction findings (AH, HV intervals)
- Response to pacing
- Implications for therapy
Modifier Rules for EP Study Billing
Modifier use is heavily audited.
Modifier 26
Use when performing interpretation only (e.g., hospital-based).
Modifier 59 / XS
May be used when add-on mapping or LV pacing is performed as a truly separate service.
Must be supported clearly.
Modifier 52
For reduced services when the full EP study could not be completed (e.g., patient instability).
No modifier 25
Do not add modifier 25 to an E/M visit on the same day unless:
- The visit is unrelated AND
- There is a separate diagnosis AND
- Documentation shows distinct decision-making
Common EP Study Denials and How to Prevent Them
Insufficient Documentation
Most denials relate to missing documentation of:
- Chamber involvement
- Stimulation specifics
- Mapping purpose
- Drug testing purpose
Unbundling Errors
Examples:
- Billing 93620 + 93619 (not allowed)
- Billing catheter placements separately
- Billing standard pacing as add-on codes
Missing Medical Necessity
Payers expect clear diagnostic need when:
- No sustained arrhythmia was seen on ECG
- Prior Holter/event monitor did not show arrhythmia
- Syncope evaluation lacked supporting documentation
Mapping Denials
93613 and 93662 are audited because they increase reimbursement.
Every mapping or ICE procedure must include:
- Reason
- Technique
- Interpretation
Drug Testing Denials
93623 requires documentation that drug infusion was only for arrhythmia induction—not for sedation or perfusion support.
Audit-Ready Documentation Phrases
These statements strengthen claims:
- “Left atrial pacing performed as part of comprehensive EP study per CPT 93620.”
- “Left ventricular pacing performed to evaluate conduction disease; billed per CPT 93621.”
- “Drug infusion (isoproterenol) administered solely for arrhythmia induction—CPT 93623 indicated.”
- “ICE used to confirm transseptal puncture and catheter position—CPT 93662 supported.”
EP Study Billing Scenarios (Practical Examples)
Scenario 1 – Full EP Study
Catheters in RA, RV, His, CS. No LV or mapping.
→ 93619
Scenario 2 – Comprehensive EP Study With Left Atrial Pacing
→ 93620
Scenario 3 – Comprehensive EP Study + LV pacing
→ 93620 + 93621
Scenario 4 – Comprehensive EP Study + Mapping
→ 93620 + 93613
Scenario 5 – EP Study + Drug Infusion
→ 93620 + 93623
Scenario 6 – EP Study Turned Into Ablation
→ Use ablation codes (93653–93656)
→ Do NOT bill 93619/93620
Conclusion
Electrophysiology study billing requires a strong understanding of what each CPT code includes, how add-on codes work, which services are inherently bundled, and how to document the pacing, mapping, stimulation, and drug infusion protocols correctly. Because EP services generate frequent payer audits, clear procedural reports, vessel/chamber detail, and precise documentation of mapping, LV pacing, or drug infusion requirements are essential. Many practices strengthen accuracy and audit readiness by implementing structured EP reporting templates or by using specialized cardiology RCM partners such as Global Tech Billing LLC, mentioned here per your request.
FAQs
1. What is included in a comprehensive EP study (93619/93620)?
Catheter placement, baseline electrograms, His recording, atrial/ventricular pacing, and arrhythmia induction attempts.
2. Can 93619 and 93620 be billed together?
No. They are mutually exclusive comprehensive EP study codes.
3. When is 93621 appropriate?
When left ventricular pacing and recording are performed and documented.
4. What documentation is required for 93623 drug infusion?
Medication name, dose, duration, and confirmation that infusion was solely for arrhythmia induction.
5. Is ICE (93662) separately billable?
Yes, if documentation shows it was medically necessary and not simply part of routine catheter navigation.
6. When can mapping (93613) be billed?
When 3D mapping is performed for diagnostic clarity or procedural planning—not when it’s simply used to guide ablation.
7. Are catheter placement codes separately billable?
No, catheter placement is bundled into all EP study and ablation codes.
8. What causes most EP denials?
Missing chamber documentation, incorrect unbundling, and insufficient detail about mapping or drug infusion.
