Mason Marcus, MD
Mason Marcus, MD is a Clinical Cardiac Electrophysiology Physician in Dallas, TX, registered under NPI 1003300617. This provider registers 4 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
Here is what surrounds this office in Dallas, based on OpenStreetMap data collected Aug 28, 2026. Parking is available about 0.27 mi away at Staff Garage 2. The nearest transit stop is 465 ft away, served by Harry Hines @ Butler - N - NS. A pharmacy sits 230 ft from the entrance (UT Southwestern Campus Pharmacy), which helps if you leave with a prescription.
Getting here and what is nearby
Transit Harry Hines @ Parkland - S - MB 13 ft ~1 min
Pharmacy UT Southwestern Campus Pharmacy 230 ft ~1 min
5303 Harry Hines Boulevard, 75390
Mo-Fr 08:30-17:00
Transit Harry Hines @ Butler - N - MB 247 ft ~1 min
Transit Harry Hines @ Butler - N - NS 465 ft ~2 min
Restaurant Arby's 518 ft ~2 min
5350 Harry Hines Boulevard, Dallas 75235
10:00-23:00
Restaurant Mike Anderson's Barbeque 798 ft ~4 min
5406 Harry Hines Boulevard
Parking Faculty Parking Lot 1 1,029 ft ~4 min
5222 Southwestern Medical Avenue
Restaurant Wendy's 1,006 ft ~4 min
5502 Harry Hines Boulevard, Dallas 75235
Mo-Sa 07:00-20:00; Su 08:00-20:00
Parking Faculty Garage 1 0.23 mi ~5 min
2000 Inwood Road
Parking Staff Garage 2 0.27 mi ~6 min
2000 Inwood Road, 75390
Gas station Chevron 0.36 mi ~8 min
2606 North Stemmons Freeway
Convenience 7-Eleven 0.42 mi ~9 min
4840 Harry Hines Boulevard, Dallas 75235
Gas station 7-Eleven 0.42 mi ~9 min
Gas station 7-Eleven 0.46 mi ~10 min
2607 North Stemmons Freeway
Convenience 7-Eleven 0.47 mi ~10 min
Hotel Embassy Suites by Hilton Dallas Market Center 0.50 mi ~11 min
Distances are straight‑line estimates — walking routes may be longer. Hours and phone numbers can change; call ahead to confirm.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| MD2026-0339 | NM | Clinical Cardiac Electrophysiology… primary |
| T5387 | TX | Internal Medicine Physician |
| MD2026-0339 | NM | Cardiovascular Disease Physician |
| 276344 | MA | Student in an Organized Health Care… |
Licences are recorded in 3 states: NM, TX, MA. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Internal Medicine
- PAC ID
- 8426306713
- Enrollment ID
- I20260625000464
Medicare enrolment is recorded as approved under the provider type Practitioner - Internal Medicine. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 3 states
This provider holds licences in 3 states: Massachusetts, New Mexico and Texas. The practice address on file is in Dallas, TX, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- 276344
- Specialty
- Student in an Organized Health Care…
- Licence
- MD2026-0339
- Specialty
- Clinical Cardiac Electrophysiology…
- Licence
- T5387
- Specialty
- Internal Medicine Physician
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Clinical Cardiac Electrophysiology covers
A field of special interest within the subspecialty of cardiovascular disease, specialty of Internal Medicine, which involves intricate technical procedures to evaluate heart rhythms and determine appropriate treatment for them. NUCC Health Care Provider Taxonomy, code 207RC0001X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207RC0001X | Clinical Cardiac Electrophysiology Physician Clinical Cardiac Electrophysiology | MD2026-0339 | NM | primary |
| 207R00000X | Internal Medicine Physician | T5387 | TX | |
| 207RC0000X | Cardiovascular Disease Physician Cardiovascular Disease | MD2026-0339 | NM | |
| 390200000X | Student in an Organized Health Care Education/Training Program | 276344 | MA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1003300617 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jun 18, 2018 |
| Last updated | Jun 15, 2026 |
| Status | Active |
| Sole proprietor | No |
| Gender | Male |
| Credential | MD |
| Practice address |
5323 HARRY HINES BLVD Dallas, TX 75390 (214) 645-8000 |
| Mailing address |
2844 ALDEN AVE Dallas, TX 75211 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 0 | 3 | 3 | 0 | 0 | 6 | 1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 6 | 0 | 0 | 6 | 2 |
Sum = 43 · next multiple of 10 = 50 · check digit = 7 · actual last digit = 7
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.