More than 5,550 clinicians must take part in Medicare's mandatory Ambulatory Specialty Model starting in January 2027, according to the American College of Cardiology's September 15, 2026 report on the final CMS participant list. Of those, 2,215 are in the heart failure cohort.
The model changes Part B payment by up to 9% in its first payment year and up to 12% by its last, according to Benesch's December 3, 2025 summary of the final rule. The adjustment applies to every Part B dollar a participant bills, so it reaches well past the two conditions the model tracks.
Who is on the participant list
The ACC counted more than 5,550 clinicians on the final list, with 2,215 in the heart failure cohort. The ACC also reported that CMS added no new participants beyond the preliminary list it published in February 2026. In the rule, CMS had projected about 8,600 physicians in the selected areas, according to Benesch. The ACC also noted that many physicians in cardiology subspecialties such as electrophysiology, interventional cardiology, and advanced heart failure and transplant remain on the list. CMS proposed an exception process for heart failure specialty changes in the 2027 fee schedule proposed rule.
Eligibility rests on specialty, location and volume. Forvis Mazars, in a January 16, 2026 article, reports that general cardiology is the only specialty in the heart failure track. The low back pain track covers anesthesiology, pain management, interventional pain management, neurosurgery, orthopedic surgery, and physical medicine and rehabilitation.
Location is set by CMS, not by the practice. Forvis Mazars reports that CMS selected core-based statistical areas (CBSAs) and metropolitan divisions at random, with a 40% probability, from six stratified groups. Benesch cites CMS projections that this covers roughly one-quarter of all CBSAs and metropolitan divisions.
A clinician also needs volume. Both Benesch and Forvis Mazars state a minimum of 20 attributed heart failure or low back pain episodes in a 12-month period for Original Medicare beneficiaries. Eligibility is assessed for each physician, not for the practice as a whole.
How much payment is at risk
The model is two-sided. A participant can gain or lose a share of Part B payments, and the share grows each year. Benesch reports no opt-out and no hardship exemption, and the model does not qualify as an Advanced APM, so it carries no 5% APM bonus.
| Performance year | Payment year | Maximum upside or downside |
|---|---|---|
| 2027 | 2029 | 9% |
| 2028 | 2030 | 9% |
| 2029 | 2031 | 10% |
| 2030 | 2032 | 11% |
| 2031 | 2033 | 12% |
Source: Benesch, December 3, 2025, summarizing the CY 2026 Medicare physician fee schedule final rule of October 31, 2025. The National Law Review's December 9, 2025 article gives the same endpoints, 9% in 2029 and 12% by 2033.
Benesch states that the adjustment applies to all Part B allowed charges, not only to heart failure or low back pain services. Take a physician with $500,000 in annual Part B allowed charges. By simple arithmetic, a 9% adjustment moves $45,000 and a 12% adjustment moves $60,000. The $500,000 figure is a round input for the calculation, not data from any practice.
How the score is built
Forvis Mazars and Benesch both report that quality counts for 50% of the score and cost for the other 50%. Two further categories can only subtract. Benesch reports that improvement activities can lower the score by up to 20 points and promoting interoperability by up to 10 points.
The final rule also adds points. Benesch reports up to 10 points for treating complex patient populations, measured by HCC risk and dual-eligible share, and up to 10 points for solo clinicians and practices of 15 or fewer clinicians. The total is capped at 100 points. Forvis Mazars reports that CMS converts the aggregate score into a payment factor with a logistic function.
The National Law Review reports two further rules. Performance is attributed only to participants who had at least one visit with the beneficiary. Small practices can report quality measures at the Taxpayer Identification Number level. Participants must also set up collaborative care arrangements with primary care providers who share at least one model beneficiary with them.
Volume and spending CMS projects
Benesch lists CMS projections of about 600,000 heart failure and low back pain episodes a year, about 550,000 beneficiaries and about $2.8 billion in annual episode spending. Dividing the spending by the episodes gives about $4,667 per episode, an average calculated from those two projections.
The model runs five performance years, 2027 through 2031, with payment adjustments applied from 2029 through 2033, according to Benesch and the National Law Review. Benesch also reported that CMS expected to issue more operational guidance in late 2026.
What a practice can check now
Start with the participant list. The ACC article links to the CMS data page for the list, and each clinician in the selected specialties can be looked up by name. The ACC reports that once the proposed exception process is final, incorrectly selected participants can submit specialty documentation for removal, and it said it would share instructions when available.
Next, find the Part B base. Pull each listed clinician's annual Medicare Part B allowed charges from the billing system. Multiply by 9% for the first payment year to see the amount exposed in 2029, then by 12% for 2033.
Then count episodes. A clinician below 20 attributed episodes in a 12-month period does not meet the volume minimum. Practices with 15 or fewer clinicians also qualify for the small practice score bonus of up to 10 points.
The first performance year starts January 1, 2027, and the first payment adjustment lands in 2029.
Sources
- American College of Cardiology, CMS Releases Final Ambulatory Specialty Model Participant List For 2027, September 15, 2026
- Benesch, CMS Finalizes Mandatory Ambulatory Specialty Model for Heart Failure and Low Back Pain Specialists, December 3, 2025
- Forvis Mazars, What Physicians Should Know About CMS' Ambulatory Specialty Model, January 16, 2026
- National Law Review, Ambulatory Specialty Model Final Rule: Bringing Specialists Into Value-Based Payment, December 9, 2025
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