Tx l/r atrial fib addl
CPT code 93657 covers the additional work when a physician performs ablation (controlled destruction of heart tissue) on both the left and right atria to treat atrial fibrillation during the same procedure session. This is an add-on code used only when ablation is performed on both chambers beyond the initial procedure.
RVU breakdown
Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High
Billing tips
Always verify that a primary ablation code (93653, 93654, or 93656) is billed on the same claim before submitting 93657, as this is an add-on code that cannot stand alone
Impact: Prevents 100% denial ($290.80 loss) and expedites clean claim processing; reduces rework and appeals costs
Document specific anatomic sites ablated in both left atrium (beyond pulmonary veins: roof line, mitral isthmus, posterior wall) and right atrium (CTI, SVC, other sites) with mapping evidence and ablation parameters
Impact: Critical for audit defense; inadequate documentation leads to recoupment of $290.80 plus potential extrapolation in RAC audits affecting multiple claims
Verify that the primary ablation code represents work on a different atrial chamber or different ablation targets than 93657 to avoid unbundling violations
Impact: Prevents compliance violations and False Claims Act exposure; incorrect unbundling can trigger OIG investigation beyond simple payment recovery
When bilateral ablation is planned but only partially completed, use modifier 53 and reduce charge proportionally based on work completed; do not bill full 93657
Impact: Ensures compliant billing; full billing for incomplete procedures risks fraud allegations and license board complaints beyond $290.80 overpayment
Review payer-specific LCD/LCA policies for 93657 as some Medicare MACs and commercial payers have specific coverage criteria requiring demonstration of complex arrhythmia substrates
Impact: Pre-procedure verification prevents denials; approximately 15-20% of 93657 claims denied for medical necessity annually
Bill facility and professional components separately with appropriate place of service codes; 93657 has identical facility and non-facility rates ($290.80) but documentation requirements differ
Impact: Ensures correct payment pathway; facility billing errors delay payment by 30-45 days on average
Common denials
Billed without a primary ablation procedure code (93653, 93654, or 93656) on the same claim or operative session
How to appeal: Submit corrected claim with both primary and add-on codes; include operative report clearly documenting all ablation sites. If codes were split across claims, request claim adjustment with explanatory letter citing same operative session with date/time documentation.
Medical necessity denial due to insufficient documentation demonstrating ablation of both left and right atrial structures beyond pulmonary vein isolation alone
How to appeal: Submit complete electrophysiology study report with detailed mapping data, ablation catheter positions, lesion sets created in both atria, and pre/post-ablation rhythm documentation. Include clinical notes explaining why bilateral comprehensive ablation was medically necessary based on arrhythmia complexity.
Bundling denial with primary ablation code due to payer edit viewing 93657 as inclusive component rather than separately reportable add-on service
How to appeal: Cite CPT guidelines defining 93657 as add-on code explicitly designed for bilateral ablation work. Reference CMS NCCI edits showing 93657 is not bundled with appropriate primary codes. Submit LCD/NCD documentation supporting separate payment. Request peer-to-peer review with medical director.
Duplicate service denial when multiple ablation add-on codes billed together without clear differentiation of distinct services
How to appeal: Provide anatomic diagram or mapping system screenshots showing distinct ablation lesion sets. Document time spent on each component. Use appropriate modifiers (59/XU) if billing other add-on procedures. Include electrophysiologist attestation of separate, medically necessary services.
Frequently asked questions
What is CPT code 93657 used for?
CPT code 93657 is an add-on code used to report additional physician work when performing comprehensive catheter ablation of both the left and right atria for treatment of atrial fibrillation during the same procedure session. It must be billed with a primary ablation code (93653, 93654, or 93656) and cannot be reported alone.
How much does Medicare pay for CPT 93657 in 2025?
Medicare pays $290.80 for CPT code 93657 in 2025 based on the national average rate. This rate is identical for both facility and non-facility settings. The code carries 8.99 total RVUs (5.5 work RVUs, 2.24 practice expense RVUs, and 1.25 malpractice RVUs) multiplied by the 2025 conversion factor of 32.3465.
Can CPT 93657 be billed alone?
No, CPT 93657 is an add-on code designated by the '+' symbol in CPT manuals and must always be reported with a primary atrial fibrillation ablation code such as 93653, 93654, or 93656. Billing 93657 without a qualifying primary procedure will result in automatic denial.
What documentation is required to bill CPT 93657?
Documentation must include a complete operative report detailing specific ablation sites in both the left atrium (beyond pulmonary veins) and right atrium, electroanatomic mapping data, ablation parameters for each lesion set, pre- and post-procedure rhythm strips, and clear medical necessity justification for bilateral comprehensive ablation. The report must demonstrate work beyond the primary ablation code.
What is the difference between CPT 93656 and 93657?
CPT 93656 is a primary procedure code for comprehensive left atrial ablation including pulmonary vein isolation, while 93657 is an add-on code reporting additional work when ablation extends to both left and right atrial structures. Code 93657 is billed in addition to 93656 when bilateral ablation is performed during the same session.
How many RVUs is CPT code 93657 worth?
CPT code 93657 has 8.99 total RVUs in 2025, consisting of 5.5 work RVUs, 2.24 practice expense RVUs (both facility and non-facility), and 1.25 malpractice RVUs. This represents substantial physician work reflecting the complexity of bilateral atrial ablation procedures.
What are common denial reasons for CPT 93657?
Common denials include billing 93657 without a primary ablation code, insufficient documentation proving ablation of both atrial chambers, medical necessity denials when only pulmonary vein isolation is documented, and bundling edits when payers incorrectly view the service as included in the primary procedure. Each denial requires specific documentation and appeals strategies to overturn.