National Cardiology Supply by State — NPPES 2026 Snapshot

Heart disease has been the leading cause of death in the United States for over a century. The American Heart Association's annual Heart Disease and Stroke Statistics update reports that cardiovascular disease accounts for roughly one in three U.S. deaths, and the burden falls unevenly across states — with rural and Southern states carrying both the highest cardiovascular mortality and, frequently, the lowest cardiologist density.

The American College of Cardiology's workforce reports have flagged a structural undersupply of cardiologists relative to demand, particularly outside major metropolitan areas. National headlines on cardiology supply average across high- and low-density states; the state-level picture is what consumers and policy readers actually feel.

This study reports what the public NPPES dataset shows: every active NPI-1 cardiologist (NUCC parent code 207RC0000X — Internal Medicine, Cardiovascular Disease) bucketed by Practice Address state and divided by U.S. Census Bureau 2024-vintage state population. It is a density measurement at state granularity — not a spatial-access model, not an outcomes study, and not a count of all cardiology subspecialists.

Source. The U.S. Centers for Medicare & Medicaid Services (CMS) National Plan and Provider Enumeration System (NPPES) — the public NPI Registry. Every U.S. healthcare provider who bills any payer (commercial, Medicare, Medicaid) holds an NPI; NPPES is the registry of record for that identifier. The public API at https://npiregistry.cms.hhs.gov/api/?version=2.1 requires no authentication and is updated continuously by CMS as providers self-attest changes.

Counted (kept). Each provider in our snapshot meets all three criteria:

1. Type 1 NPI (individual practitioner). Type 2 NPIs (organizations / group practices) are a separate analysis surface and are not counted here.

2. Active — basic.status = "A" and basic.deactivation_date is null.

3. At least one Healthcare Provider Taxonomy code in the cardiology family:

   • 207RC0000X — Internal Medicine, Cardiovascular Disease (parent)

This study counts only physicians whose primary NPPES taxonomy is the parent cardiology code (207RC0000X). Subspecialties (Interventional Cardiology 207RI0011X, Clinical Cardiac Electrophysiology 207RC0001X, Adult Congenital Heart Disease 207RA0001X, Advanced Heart Failure 207RH0000X) carry their own codes and are out of scope. Cardiac surgeons (208G00000X), cardiology APPs, and cardiology-focused nurse practitioners (363LC0200X) are also out of scope and would be a separate study.

State assignment. Each NPI's Practice Address (LOCATION) state is used, not the Mailing Address. NPPES distinguishes the two; for cross-state telemedicine practices the Practice Address state may differ from where the provider primarily lives.

Not counted. Providers with deactivated NPIs, providers whose only cardiology-adjacent taxonomy is outside the codes above, residents and fellows whose primary taxonomy is the "Student" code (390200000X), and providers without a U.S. Practice Address.

The national rate of 10.29 active cardiologists per 100,000 residents is a single number; the state spread is what consumers, providers, and policy readers actually feel.

Top 5 by density:

• District of Columbia — 21.79 / 100k (n=153)
• Massachusetts — 18.10 / 100k (n=1,292)
• Connecticut — 16.46 / 100k (n=605)
• New York — 15.66 / 100k (n=3,111)
• Pennsylvania — 14.39 / 100k (n=1,882)

Bottom 5 by density:

• Idaho — 5.10 / 100k (n=102)
• Wyoming — 5.45 / 100k (n=32)
• Utah — 6.05 / 100k (n=212)
• Alaska — 6.08 / 100k (n=45)
• New Mexico — 6.57 / 100k (n=140)

The lowest-density state holds approximately 23% of the highest-density jurisdiction's per-capita supply. The chart below shows the full ranking; the dashed marker is the 4-per-100k threshold this study uses to flag underserved jurisdictions.

0 jurisdictions rank below the 4 active cardiologists per 100,000 residents threshold this study uses to flag underserved jurisdictions. The threshold is a transparent baseline cutoff stated explicitly here — it is not a clinical or regulatory definition. Stated baseline cutoff aligned with workforce-adequacy thresholds in the American College of Cardiology cardiovascular workforce literature, which puts the lower bound of national-average cardiologist density around 7–10 per 100,000 with bottom-quartile states at 3–5. We use 4 / 100k as the underserved cutoff. Stated explicitly here; not a clinical or regulatory definition.

The states below the threshold collectively hold 0 residents — about 0.0% of the U.S. population.

Important framing. "Underserved" here means density-below-threshold in the public NPPES dataset. It does not measure new-patient availability, insurance acceptance, sub-specialty match, travel time to the nearest practice, or whether the practice is accepting Medicaid. Network-distance and gravity-model methodologies produce a different, complementary picture — one we explicitly cite below.

Density per 100,000 residents is the most transparent supply baseline. It uses two public datasets, requires no modeling assumptions beyond arithmetic, and can be audited row-by-row in the downloadable dataset. Every reader can audit the numbers themselves.

It is not spatial access. A patient in a rural state and a patient in a metropolitan state both contribute the same "1" to their state's denominator, but their realized access differs by orders of magnitude. Headline figures derived from network-distance models (e.g. "X% of Americans live within Y minutes of a [specialist]") coexist with the present study's state-level density findings — both can be true simultaneously, because density and proximity capture different facets of "access."

The healthcare workforce literature has more advanced approaches:

• Two-Step Floating Catchment Area (E2SFCA) and gravity models treat access as a function of provider supply, population demand, and distance decay. A 2023 review of gravity models for potential spatial healthcare access (open-access spatial-epidemiology literature) is the standard reference.
• Network-based access measures compute drive-time isochrones from each Census tract centroid and count reachable providers within a window.

This study does not implement E2SFCA, gravity, or network distance. It reports state-level density and acknowledges the gap. Readers who need spatial-access estimates should pair our state ranking with the cited literature or specialty-specific access modules in the AAMC State Physician Workforce Data Reports.

Public-health relevance. The American Heart Association's annual Heart Disease and Stroke Statistics update consistently flags state-level disparities in cardiovascular mortality. Lower cardiologist density correlates with delayed diagnosis, fewer guideline-directed therapies, and higher excess mortality from preventable cardiovascular events — particularly in rural counties where the marginal value of one additional cardiologist is highest because there's often no nearby alternative.

Capacity-expansion vehicles flagged in the cardiology workforce literature: tele-cardiology (post-pandemic, geography-blind monitoring), advanced practice provider (APP) integration in cardiology clinics, and hub-and-spoke partnerships between academic medical centers and rural hospitals. None of these alters the NPI-1 cardiologist count this study tracks — but each materially changes patient-facing capacity. Future versions of the study may add parallel tracks for APP density once that is methodologically defensible to surface.

Citation transparency. This study makes no clinical claims about any individual provider. The density-to-outcomes link is documented in the cardiovascular-policy literature; we cite it as context for why density matters, not as a finding our dataset proves.

Most state-level cardiology supply numbers in circulation come from one of three places: (1) the AAMC State Physician Workforce reports, which use specialty-society membership and AMA Masterfile cross-references; (2) commercial workforce-data vendors that license those underlying datasets; or (3) press-release figures from advocacy organizations.

This study is different in three concrete ways:

1. Single public source family. Everything reported here ties back to the public NPPES API and the public Census Bureau population estimate. Both are free. Both are updated on cadences CMS and Census publish. Anyone with a web browser can re-run the underlying queries.
2. Record-level traceability. Every provider in the count has an NPI. The downloadable dataset preserves NPI numbers, the matched state, and the per-state aggregate. A reader auditing a specific state's count can pull the corresponding NPI list, look each one up in NPPES, and audit the active-cardiology-taxonomy criterion themselves.
3. No quality attestation. Fonteum does not run a checking process for individual cardiologists. The label "active in NPPES" describes a CMS registry status, not a quality, board-certification, or insurance-acceptance attestation. Patients who need clinical confirmation should consult the American Board of Medical Specialties (ABMS) registry for board-certification status and their insurer's directory for in-network availability.

The downloadable CSV at the top of this study includes per-state count, density, rank, quartile, and the underserved-threshold flag. The downloadable JSON adds the snapshot metadata and source URLs.

Suggested citation:

Ownlisted Research. (2026). National Cardiology Supply by State — NPPES 2026 Snapshot. Ownlisted. Retrieved from https://fonteum.com/research/cardiology-supply-by-state-2026

Reuse and attribution. Charts, tables, and the downloadable CSV / JSON may be cited or reproduced with attribution to Ownlisted Research and a link to this study. Carry the snapshot date (2026-05-06) so readers know the dataset version. Future NPPES snapshots will produce different state-level counts as providers update their NPPES status.

The methodology, the explicit underserved-threshold definition, and the density-vs-spatial-access distinction must travel with the figures. Per-state counts published without those caveats risk being misread as a clinical-access measurement, which the dataset does not support.

Press / media inquiries. Reach the Ownlisted Research team via the brand-hub contact page. We are happy to clarify methodology for health-policy and access-equity reporters; we will not provide patient-side clinical commentary.

Cited literature (suggested for follow-up reading):

• American College of Cardiology — most recent cardiovascular workforce report. The standard reference for U.S. cardiologist supply, demand, and projection forecasts.
• American Heart Association. Heart Disease and Stroke Statistics — annual update. State-level cardiovascular mortality and morbidity statistics.
• Peer-reviewed cardiology workforce studies (e.g., Health Affairs, JACC, Circulation) on density-to-outcomes linkage in U.S. cardiovascular care delivery.
• Gravity models for potential spatial healthcare access (2023). Methodological reference for E2SFCA and gravity-decay approaches not implemented here.

• Density is not spatial access. Per-100,000 resident density measures supply-to-population ratio at the state level. It does not measure travel time, new-patient availability, insurance acceptance, or sub-specialty match. Network-based and gravity-decay methods (E2SFCA) provide more accurate access measurements. We have not implemented those methods.
• NPPES taxonomies are self-reported. Providers select their own taxonomy codes when registering or updating their NPI. There is no specialty-board cross-check built into NPPES; a board-certified physician and a non-board-certified provider who self-attests the specialty code both appear. Patients confirming clinical credentials should consult ABMS / AOA registries directly.
• Practice Address state, not where the provider lives or practices most. A multi-site practitioner is counted once at their Practice Address state. Cross-state telemedicine practices may be undercounted in the patient-facing state.
• Active-flag accuracy. NPPES updates active/deactivated status as providers self-attest. Some providers carry stale NPIs from earlier career stages. The deactivation flag captures most cases; minor over-counting at the margin is possible.
• Census ACS 2024 vintage uncertainty. State population denominators come from the Census Bureau 2024 V2024 estimate. ACS estimates carry margin-of-error bands; per-100k figures are point estimates from a point-estimate denominator and should not be treated as exact to two decimal places.
• No procedure-mix or sub-specialty breakout. This study does not distinguish sub-specialties beyond what the taxonomy codes encode. A provider's primary clinical practice may differ from their NPPES taxonomy code.
• Type 2 (organization) NPIs excluded. Hospital-employed cardiologists who only operate under a Type 2 organization NPI are under-counted. Most cardiologists carry both, so the under-count effect is small but non-zero.
• No outcomes / quality-of-care claims. This study reports NPPES-listed counts and Census-derived densities. It makes no claims about practice quality, board certification status, sub-specialty expertise, or any clinical outcome metric. This is not medical advice. Patients should look up board certification through ABMS or AOA, confirm insurance acceptance with the practice, and consult their primary care physician for referrals.
• Snapshot in time. Counts reflect the 2026-05-06 NPPES snapshot. The cached dataset is preserved at data/nppes/cardiology-2026-05-06.json for re-analysis.