Section analysis by Tatiana Kantor, CFPC, CPB, Billing Department, WCH
EDITOR’S NOTE: CMS finalized the Ambulatory Specialty Model (ASM) as part of the CY 2026 Medicare Physician Fee Schedule Final Rule, published October 31, 2025. The preliminary participant list was released in early 2026; the final participant list is expected in July 2026. ASM performance begins January 1, 2027. This section covers what general cardiology practices need to know now, while there is still time to prepare.
What the ASM Is and Why It Is Different From Everything That Came Before
The Ambulatory Specialty Model aims to improve prevention and upstream management of chronic disease, which would lead to reductions in avoidable hospitalizations and unnecessary procedures. Participation in ASM will be mandatory for specialists who commonly treat people with Original Medicare for heart failure in an outpatient setting across selected regions. ASM will begin on January 1, 2027, and run for five performance years through December 31, 2031.
The word mandatory carries real weight here, and it is worth reading carefully. Participation is mandatory — clinicians meeting ASM criteria within selected geographic markets will be automatically included, with no opt-out or hardship exemption pathway. CMS also confirmed that ASM is not designated as an Advanced APM under MACRA and therefore does not qualify participants for the 5% APM incentive bonus.
That last point deserves a second read. A cardiologist required to participate in ASM does not receive the APM incentive payment that participation in a qualifying advanced alternative payment model would normally generate. They absorb the financial risk, take on the reporting burden, and receive none of the incentive bonus. The ACC has flagged this asymmetry in its formal comments to CMS, and the agency made no substantive changes in the final rule.
An estimated 8,600 physicians will be required to participate. The model will span seven years, with five performance years running 2027–2031 and corresponding payment years running 2029–2033. The payment lag — two years between performance and financial consequence — mirrors the MIPS structure, but the stakes are different. Under ASM, payment adjustments of up to 9–12%, depending on the performance year, apply to all Medicare Part B services, not just the subset of services covered by a MIPS measure.
Who Is Included — and Who Is Explicitly Excluded
The eligibility criteria are specific, and the exclusions matter as much as the inclusions.
The model limits participants to Medicare PECOS-enrolled cardiologists while excluding cardiovascular subspecialties, including interventional cardiology, electrophysiology, and advanced heart failure and transplant. For practices that operate as multispecialty cardiology groups — with general cardiologists, interventionalists, and electrophysiologists under the same TIN — the attribution and eligibility analysis needs to be done at the individual clinician level, not the group level. A general cardiologist in a large cardiology group may be enrolled in ASM while colleagues in the same practice are not.
Participants are identified through retrospective analysis of Medicare claims data rather than a voluntary enrollment process. Clinicians and practices are identified based on historical outpatient care patterns for beneficiaries with heart failure, using objective utilization and billing data. Since the selection process is claims-driven, practices may not fully recognize their exposure to ASM until they receive formal notification.
The practical implication: general cardiology practices with meaningful heart failure patient populations in selected geographic areas should assume they are potentially in scope and act accordingly. CMS released the selected geographic areas and a preliminary list of participants in early 2026. The final participant list is expected in summer 2026. Practices that have not verified their status against the preliminary list should do so now.
How Performance Is Measured and What Drives Payment Adjustments
Under ASM, participants’ performance will be assessed across four categories: Quality, Cost, Improvement Activities, and Improving Interoperability — the same framework as MIPS, but with measures targeted to heart failure management.
The quality measures reflect what the ACC has long argued should drive cardiology reimbursement: blood pressure control in heart failure patients, functional status assessments, avoidable cardiovascular hospitalizations, and guideline-directed medical therapy adherence. These aren’t abstract administrative measures — they reflect the clinical work general cardiologists perform every visit. The problem is that capturing them reliably requires structured data collection at the point of care, which many cardiology practices haven’t fully built out.
Beneficiary attribution will be prospective and based on the plurality of evaluation and management visits during the attribution window, providing predictability for care planning and workflow design. Prospective attribution is a meaningful design feature. Unlike retrospective attribution models where the practice discovers at year-end which patients were attributed, ASM’s prospective approach allows cardiologists to identify their attributed heart failure population before the performance year begins and proactively manage their care.
The cost accountability piece is where the financial risk becomes concrete. ASM will hold participants financially responsible for the outcomes of their care, incentivizing better prevention and management of heart failure to reduce avoidable hospitalizations and unnecessary procedures. Total cost of care for attributed heart failure patients — including inpatient admissions the patient’s primary care physician or hospitalist managed — factors into performance. A patient with poorly controlled heart failure who is admitted to the hospital is a cost event for the ASM-participating cardiologist even if the cardiologist wasn’t directly involved in that admission.
The ACC’s Concerns — and What They Mean for Practices
The ACC is concerned that CMS chose to keep the proposed changes to site of service payment differential and efficiency adjustment, despite widespread concerns from the medical community. The ACC highlighted that the individual-level focus and lack of team-based care principles, issues with the patient attribution framework, and several operational and design flaws could limit effectiveness.
The team-based care concern is operationally significant. Heart failure management in the real world involves cardiologists, nurse practitioners, pharmacists, care coordinators, and primary care physicians. ASM holds the cardiologist financially accountable for outcomes across that entire care team — without giving the cardiologist direct authority over how other clinicians manage the patient. A general cardiologist whose attributed heart failure patients are also seeing NPs and PAs at a primary care practice has limited visibility into, and no contractual leverage over, those encounters.
What Cardiology Practices Should Do Between Now and January 2027
The six months between now and the ASM start date are the most valuable compliance window available.
Verify enrollment status. Practices should check the preliminary participant list CMS released in early 2026 and identify which individual clinicians within the group are enrolled. Don’t assume group-level status applies uniformly.
Assess attribution risk. Pull claims data for the past two calendar years and identify patients with HF diagnosis codes who had a plurality of E/M visits with general cardiology clinicians in the practice. That population approximates the attributed panel under ASM. Size matters: the model applies only to physicians who treated at least 20 Medicare heart failure episodes per year based on the episode-based cost measure threshold.
Build structured quality data capture into EHR workflows now. Blood pressure documentation, functional status assessments, GDMT medication reconciliation — these need to be captured in structured, extractable fields, not free text. Practices that run on free-text notes will have a hard time generating the data required for ASM quality reporting.
Engage with the ACC’s educational resources. The ACC has committed to producing webinars, Q&A materials, and practice guidance specifically for ASM-participating cardiologists. The final participant list is announced in summer 2026, and ASM Year 1 begins January 1, 2027. Use the time between those two dates to close operational gaps, not learn the rules.
Key ASM Timeline
| Milestone | Date |
| ASM finalized in CY 2026 MPFS Final Rule | October 31, 2025 |
| Preliminary participant list released | Early 2026 |
| Final participant list published | July 2026 |
| ASM Year 1 begins | January 1, 2027 |
| First payment adjustments | 2029 |
| Model concludes | December 31, 2031 |
References
- CMS. Ambulatory Specialty Model Overview. cms.gov/priorities/innovation/innovation-models/asm
- American College of Cardiology. ASM for Heart Failure: Overview and Key Considerations. acc.org
- Bass, Berry & Sims. CMS Launches Mandatory Two-Sided Risk Model for Specialists Treating Heart Failure and Low Back Pain. bassberry.com. February 25, 2026.
- Benesch Law. CMS Finalizes Mandatory Ambulatory Specialty Model. beneschlaw.com. April 14, 2026.
- ACC. Heart of Health Policy: 2026 Medicare PFS Final Rule; ASM for HF. acc.org. December 1, 2025.
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