Medicare Enrolled
Dr. Nathan Riddell, M.D.
Cardiovascular Disease · Worcester, MA
Practice pattern: Cardiac & Cardiac
— Practice combining cardiac and cardiac services
Very High
DATA COVERAGE
Data in 4 of 4 federal sources
Measures public federal data availability — not provider quality
Informational, not a quality rating.
This page presents federal public records about Dr. Riddell from CMS (NPPES, Open Payments, Medicare Provider Utilization, PECOS). It is not medical advice, an endorsement, or a judgment of clinical quality. Always consult the provider directly and a licensed clinician for medical decisions. Read methodology →
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What this data tells you about Dr. Riddell
Dr. Nathan Riddell is a cardiovascular disease specialist in Worcester, MA, with 13 years of NPI registration. Based on federal Medicare data, Dr. Riddell performed 1,910 Medicare services in 2023. These records do not provide a deduplicated patient total.
Between the years covered by Open Payments, Dr. Riddell received a total of $6,227 from 20 pharmaceutical and/or device companies across 75 payment records. A record can group multiple payments. These transfers are publicly reported through CMS Open Payments. Disclosure alone does not establish their effect on care. A reliable breakdown by payment category is not available in this snapshot. Patients may wish to discuss these relationships with their provider.
The Data Coverage level for Dr. Riddell is Very High — reflecting how much public federal data is available about this provider. Patients are encouraged to use this data as one of several factors when choosing a healthcare provider.
✓ 13 years of NPI registration
▲ 1,910 Medicare services
$6,227 industry payments
Medicare Practice Summary — 2023
Medicare Utilization ↗1,910
Medicare services
Bottom 48% in MA for cardiovascular disease
Not available
Unique patients (not deduplicated)
$71
Avg. Medicare payment
Medicare patients only (65+ / disabled) · How to read this →
Top procedures by volume
Ranked by number of services performed for Medicare patients. Avg. submitted charge is what the provider billed; avg. Medicare payment is what CMS paid.
| Procedure | Volume | Avg. paid | Avg. submitted |
|---|---|---|---|
| EKG interpretation and report A standard electrocardiogram test that records the heart's electrical activity using at least 12 leads. The service includes a professional interpretation of the results and a written report. |
630 | $6 | $28 |
| Echocardiogram, transthoracic An ultrasound of the heart that uses color to show blood flow, rate, direction, and valve function. |
297 | $67 | $564 |
| Electrocardiogram (EKG), 12-lead A standard heart rhythm test using at least 12 leads to record electrical activity. A healthcare provider interprets the results and provides a written report. |
166 | $12 | $98 |
| Hospital follow-up visit, moderate complexity Follow-up hospital visit for an existing patient involving moderate medical decision making. The visit requires at least 35 minutes of time spent on the date of service. |
121 | $64 | $240 |
| Office visit, established patient (30-39 min) A follow-up office visit for an existing patient lasting between 30 and 39 minutes. The visit involves medical evaluation and management of the patient's condition. |
88 | $102 | $358 |
| Office visit, established patient, complex (40-54 min) An office or outpatient visit for an existing patient lasting between 40 and 54 minutes. This level of service is determined by the total time spent on the date of the encounter. |
53 | $148 | $480 |
| Hospital follow-up visit, high complexity Subsequent hospital inpatient or observation care for an existing patient involving high-level medical decision making, with at least 50 minutes total time on the date of the encounter. |
50 | $100 | $343 |
| Initial hospital admission, moderate complexity Initial hospital inpatient or observation care for a new patient involving moderate-level medical decision making, with at least 55 minutes total time on the date of the encounter. |
40 | $110 | $452 |
| Initial hospital admission, high complexity Initial hospital inpatient or observation care for a new patient involving high-level medical decision making, with at least 75 minutes total time on the date of the encounter. |
39 | $143 | $667 |
| Regadenoson injection (Lexiscan) for heart stress test An injection of regadenoson, a medication used to stress the heart during diagnostic testing. |
39 | $44 | $152 |
| Cardiac catheterization | 38 | $194 | $1,098 |
| Follow-up heart ultrasound An ultrasound of the heart performed to monitor or reassess a previously identified condition or treatment progress. |
36 | $20 | $298 |
| Technetium Tc-99m tetrofosmin diagnostic injection A diagnostic injection of Technetium Tc-99m tetrofosmin used for imaging studies. |
31 | $261 | $369 |
| New patient office visit (45-59 min) An initial office visit for a new patient lasting between 45 and 59 minutes. This code covers the total time spent by the physician or qualified healthcare professional on the date of the encounter. |
30 | $139 | $542 |
| Exercise or drug-induced heart stress test with ECG A heart stress test performed using exercise or medication while monitoring the electrocardiogram under physician supervision and review. |
29 | $55 | $235 |
| Right heart catheterization with coronary angiography A procedure to insert a tube into the right side of the heart and coronary arteries to gather diagnostic information, with review by a radiologist. |
29 | $235 | $1,157 |
| Coronary stent placement A procedure to insert a stent into a coronary artery or its branch to keep it open, using balloon dilation during the process. |
26 | $429 | $2,017 |
| Sedation by physician, initial 15 minutes Administration of a drug to induce depression of consciousness by the physician performing a procedure. This code covers the initial 15 minutes of sedation for patients aged 5 years or older. |
24 | $10 | $168 |
| Nuclear stress test of heart muscle A nuclear medicine imaging test that evaluates blood flow to the heart muscle at rest and during stress using a special camera. |
18 | $372 | $1,313 |
| Emergency department visit, moderate complexity An emergency department visit for an established or new patient involving a moderate level of medical decision making. |
18 | $89 | $388 |
| Transcatheter aortic valve replacement via femoral artery A minimally invasive procedure to replace a diseased aortic heart valve using a catheter inserted through the skin and femoral artery. |
17 | $618 | $3,520 |
| Office visit for established patient An office visit for an existing patient that may not require the healthcare professional to be present. |
15 | $20 | $75 |
| External shock to heart to regulate heart beat A procedure that delivers an electric shock to the heart from outside the body to restore a normal heart rhythm. |
14 | $92 | $435 |
| Continuous ECG monitoring with transmission and review Continuous electrocardiogram monitoring for up to 30 days with symptom tracking. The data is transmitted and reviewed by a healthcare professional who provides a report. |
14 | $20 | $84 |
| New patient office visit, complex (60-74 min) | 13 | $176 | $681 |
| Right heart catheterization A procedure where a thin, flexible tube is inserted into the right side of the heart to measure pressure and oxygen levels. |
12 | $94 | $481 |
| Intravascular ultrasound of heart vessel, initial An ultrasound procedure used to evaluate a blood vessel within the heart during a diagnostic or treatment procedure. |
12 | $54 | $400 |
| Insertion of tube in right and left heart chambers and coronary artery for diagnosis with review by radiologist | 11 | $292 | $1,390 |
How to read this data: This reflects Medicare patients only (typically 65+). Payment amounts are what Medicare paid the provider, not your out-of-pocket cost. These counts do not measure clinical quality or years of experience.
21.9% high complexity
8.6% medium
69.4% routine
Industry Payment Transparency
Open Payments through 2024 ↗$6,227
Total received (2019-2024)
Avg $1,038/year across 6 years
Top 29% in MA for cardiovascular disease
A higher payment rank reflects disclosed industry relationships (consulting, research, speaking) common among subspecialists — not wrongdoing.
20
Companies
75
Payment records
Payments are publicly reported; disclosure does not establish legality · Not evidence of wrongdoing · How to interpret →
Payment categories are unavailable while the source breakdown is being rebuilt. Company and year totals do not identify how much belongs to each category.
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
2024
$1,562
2023
$2,954
2022
$1,402
2021
$129
2020
$80
2019
$100
Payments by company (2024)
Penumbra, Inc.
$854
Boston Scientific Corporation
$335
Amgen Inc.
$116
Novartis Pharmaceuticals Corporation
$95
PFIZER INC.
$83
AstraZeneca Pharmaceuticals LP
$39
Janssen Pharmaceuticals, Inc
$19
E.R. Squibb & Sons, L.L.C.
$14
AltaThera Pharmaceuticals LLC
$9
Top 3 companies account for 83.5% of 2024 payments
All-time payments by company (2019-2024) ›
ABIOMED
$2,750
Penumbra, Inc.
$1,017
Medtronic, Inc.
$1,016
Boston Scientific Corporation
$351
Novartis Pharmaceuticals Corporation
$154
Amgen Inc.
$140
Janssen Pharmaceuticals, Inc
$115
Merck Sharp & Dohme LLC
$114
PFIZER INC.
$103
Abbott Laboratories
$100
AstraZeneca Pharmaceuticals LP
$98
E.R. Squibb & Sons, L.L.C.
$67
Lantheus Medical Imaging, Inc.
$48
Astellas Pharma US Inc
$37
Esperion Therapeutics, Inc.
$29
Shockwave Medical, Inc
$28
Opsens Inc.
$23
CHIESI USA, INC.
$15
Bayer Healthcare Pharmaceuticals Inc.
$13
AltaThera Pharmaceuticals LLC
$9
Top 3 companies account for 76.8% of all-time payments
Associated products mentioned in payments ›
AVVIGO Guidance System · BRIDION · BRILINTA · CAMZYOS · COREVALVE EVOLUT R · DEFINITY · ELIQUIS · ELUVIA · ENTRESTO · FARXIGA · Impella · Indigo System · KENGREAL 50MG/10ML L · Kerendia · LEQVIO · LEXISCAN · Lexiscan · Mitra Clip system · NEXLETOL · NEXLIZET · ONYX FRONTIER · OptoWire · Repatha · SHOCKWAVE IVL SYSTEM WITH THE SHOCKWAVE C2 CORONARY IVL CATHETER · Sotalol Hydrochloride · VERQUVO · VYNDAQEL · WAINUA · Wolverine Coronary Cutting Balloon · XARELTO
Should you be concerned? Industry payments are disclosed through CMS Open Payments. Disclosure alone does not establish their purpose, legality, or effect on care. What matters is whether a recommended drug or device appears in your doctor's payment records. If so, consider asking your doctor about it. How to interpret this data →
Data Sources
| Provider Registry | ✓ NPPES | NPPES snapshot; verify current record |
| Medicare Enrollment | ✓ PECOS | PECOS snapshot |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | ✓ Open Payments | CY 2024 |
| Disciplinary History | — Not included | N/A |
This provider has data in 4 of 4 available federal datasets, with a Data Coverage level of Very High. This reflects how much public data is available about a provider. How we calculate this →
Summary
Dr. Riddell is a cardiac & cardiac specialist, with moderate Medicare volume.
This summary is auto-generated from federal data, describing data availability and patterns. Read our methodology →
Frequently Asked Questions
Is Dr. Riddell experienced with ekg interpretation and report?
Based on Medicare claims data, Dr. Riddell performed 630 ekg interpretation and report services. These records cover Medicare fee-for-service activity, including eligible younger beneficiaries; they do not measure total practice volume or clinical quality.
Does Dr. Riddell receive payments from pharmaceutical companies?
Yes. Dr. Riddell received a total of $6,227 from 20 companies across 75 payment records. A record can group multiple payments. These transfers are publicly disclosed through CMS Open Payments. Disclosure alone does not establish their legality or effect on care. Patients may wish to ask their doctor about these relationships, especially if a recommended drug or device appears in the payment records.
How do Dr. Riddell's costs compare to other cardiologists in Worcester?
Dr. Riddell's average Medicare payment per service is $71. Note that these figures represent what Medicare pays, not your out-of-pocket cost, which depends on your specific insurance plan and deductible. Procedure-level data above shows both what was submitted and what Medicare paid for each service type.
What does Data Coverage mean?
Data Coverage (currently Very High for Dr. Riddell) measures how much public federal data is available about a provider. It is not a quality rating. A "Very High" or "High" level means the provider has data across multiple federal sources (NPPES, PECOS, Medicare Utilization, Open Payments), indicating the presence of registry, enrollment, activity or payment records, not verified experience or clinical quality. A "Low" or "Moderate" level may simply mean the provider is newer, does not see Medicare patients, or has not received any industry payments — none of which are inherently negative. Read our full methodology →
Is this data up to date?
Source publication dates and the snapshots loaded on this site can differ. Rebuilding a page does not refresh its source records. Check the Medicare reporting year and the payment interval shown above; consult the linked official sources for newer releases and current registry details. See our data freshness policy →
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About this page
This page combines public CMS records with calculated summaries and explanatory procedure labels. These transformations are not verbatim federal records. Sources: NPPES ↗, Open Payments ↗, Medicare Provider Utilization ↗, and PECOS. Publication is mandated by the Physician Payments Sunshine Act (§6002 ACA, 42 U.S.C. §1320a-7h) and the Freedom of Information Act.
This page is not medical advice, an endorsement, a recommendation, or a quality rating. Data Coverage reflects data completeness — how much federal information exists for this provider — not clinical performance, patient outcomes, or quality of care. Always verify information directly with the provider and consult a licensed clinician before making medical decisions.
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