Nathan E. Riddell, M.D.

Primary specialty

Cardiovascular Disease PhysicianTaxonomy code 207RC0000X

License

273386 Issued in MA

Practice address

55 Lake Ave N
Worcester, MA 01655-0002

Phone

(508) 334-1000

NPI assigned

Jun 26, 2013

Sex

Male

Sole proprietor

No

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 2

Addresses

Medicare fee-for-service enrollment

Enrolled in MA

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 1

Specialty

Internal MedicineAlso: Cardiovascular Disease (Cardiology)

Education

Other, 2013

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

TVCG Ste PLLCGroup PAC ID 2062958846, 7 clinicians

LGH Merrimack Valley Cardiology Associates, LLCGroup PAC ID 4082886569, 22 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Lowell General Hospital Hospital, Lowell, MA, CCN 220063
• Tufts Medical Center Hospital, Boston, MA, CCN 220116

Procedures performed for Medicare patients

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: nriddell27293@tuftsmedicine.direct-ci.com

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

• LGH Merrimack Valley Cardiology Associates, LLC

  • Cardiovascular Disease Physician
  • North Chelmsford, MA
  • NPI 1952695884
  Medicare reassignment Care Compare group NPD
• TVCG Ste PLLC

  • Vascular Surgery Physician
  • Lowell, MA
  • NPI 1215661780
  Medicare reassignment Care Compare group NPD
• Sound Physicians of Massachusetts II PC

  • Internal Medicine Physician
  • Brockton, MA
  • NPI 1306376397
  Medicare reassignment NPD
• Steward Medical Group, Inc

  • Specialist
  • Watertown, MA
  • NPI 1629398219
  Medicare reassignment NPD
• Merrimack Valley Cardiology

  • Cardiovascular Disease Physician
  • Chelmsford, MA
  • NPI 1235240821
  NPD
• Steward Medical Group, Inc

  • Specialist
  • Brighton, MA
  • NPI 1356654495
  NPD

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• The Lowell General Hospital

  • General Acute Care Hospital
  • Lowell, MA
  • NPI 1407804669
  Care Compare affiliation
• Tufts Medical Center, Inc.

  • General Acute Care Hospital
  • Boston, MA
  • NPI 1730132515
  Care Compare affiliation

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1372204800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1765152000000",
    "number": "1245670983",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "55 LAKE AVE N",
            "city": "WORCESTER",
            "state": "MA",
            "postal_code": "016550002",
            "telephone_number": "508-334-1000"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "55 LAKE AVE N",
            "city": "WORCESTER",
            "state": "MA",
            "postal_code": "016550002",
            "telephone_number": "508-334-1000"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "1115 Westford St Ste 2",
            "address_purpose": "LOCATION",
            "city": "Lowell",
            "state": "MA",
            "postal_code": "018512853",
            "country_code": "US",
            "telephone_number": "351-221-7080",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "RIDDELL",
        "first_name": "NATHAN",
        "middle_name": "E.",
        "credential": "M.D.",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2013-06-26",
        "last_updated": "2025-12-08",
        "certification_date": "2025-12-08",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207RC0000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine, Cardiovascular Disease",
            "state": "MA",
            "license": "273386",
            "primary": true
        },
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "MA",
            "license": "256554",
            "primary": false
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Nicole Richford
• Rowan Luca Mars Richman
• Deanna Sahady Richmond, M.S.
• Robert I. Richmond, M.D.
• Amber Rose Ricker
• Johanna Riddle
• Adam Ridley, MD
• Alexandra Mathasen Riedel
• Eden Riel
• Theresa Riel

• Cardiovascular Disease Physician in Worcester, MA
• Providers in Worcester, MA by specialty
• Cardiovascular Disease Physician in Massachusetts

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Dec 8, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.