2026 NPPES data Clinical Cardiac Electrophysiology Physician NPI 1811542723 MD PHD
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MARK CHUBB, MD PHD

Clinical Cardiac Electrophysiology Physician in PALO ALTO, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
24
Medicare Part D claims · Clinical Cardiac Electrophysiology Physician avg: 2K
Generic prescribing
50%
generic claims · 50% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$145.09
5 payments · CMS Open Payments (Sunshine Act)
What the federal data reveals: MARK CHUBB, MD PHD is a Clinical Cardiac Electrophysiology Physician ([object Object]) practicing in PALO ALTO, California with a Medicare Part D prescribing footprint of 24 claims — 50% brand-name prescribing . Industry payments of $145.09 across 5 transactions are disclosed under CMS Open Payments (Sunshine Act).

What the federal data shows

MARK CHUBB, MD PHD filed 24 Medicare Part D claims in 2023 as a Clinical Cardiac Electrophysiology Physician in PALO ALTO, California, prescribing 50% generic.

24
Part D claims, 2023
50%
generic prescribing
$145.09
industry payments (Sunshine Act)

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

Board-eligible specialty (heuristic — not verified)

MARK CHUBB, MD PHD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

MARK CHUBB, MD PHD at a glance

Quality data not reported

NPI registry status

Active

Issued 08/07/2019

NPI 1811542723

Primary specialty

Clinical Cardiac Electrophysiology Physician

Niche

1,570 US NPIs in this specialty

Medicare Part D claims

24 98% vs specialty avg

2023 prescription claims

Specialty avg: 1,596

Specialty distribution in California

How Clinical Cardiac Electrophysiology Physician compares to other specialties among California providers

California providers

Clinical Cardiac Electrophysiology Physician share within California

1. Clinical Cardiac Electrophysiology Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Clinical Cardiac Electrophysiology Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Clinical Cardiac Electrophysiology Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Clinical Cardiac Electrophysiology Physician ABMS/AOA estimate

Est. board-certified rate (Clinical Cardiac Electrophysiology Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Clinical Cardiac Electrophysiology Physician) — ABMS / AOA estimate

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

MARK CHUBB, MD PHD is a Clinical Cardiac Electrophysiology Physician provider practicing in PALO ALTO, California, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: MD PHD. NPI: 1811542723. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

MARK CHUBB, MD PHD appears in the CMS NPPES registry as a Clinical Cardiac Electrophysiology Physician provider holding MD PHD credentials at 725 WELCH RD, PALO ALTO, CA, 94304, with a listed phone of (650) 497-8000. NPI 1811542723 was issued on 08/07/2019. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CHUBB most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 24 prescription claims written by this provider, covering N/A Medicare beneficiaries and totaling roughly $7K in drug spend, split 50% brand-name and 50% generic by claim count. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Clinical Cardiac Electrophysiology Physician is a narrow specialty nationwide, with 1,570 enrolled providers across 52 states and an average of 1,596 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

725 WELCH RD
PALO ALTO, CA 94304

Provider Details

NPI 1811542723
Specialty Clinical Cardiac Electrophysiology Physician
Credentials MD PHD
Gender Male
NPI Issued 08/07/2019

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for MARK CHUBB, MD PHD. Source: openpaymentsdata.cms.gov.

Total received

$145

Largest payer

Biosense Webster, Inc.

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

License & disciplinary context — California MBC 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 — they are NOT specific to MARK CHUBB, MD PHD. To verify MARK CHUBB, MD PHD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Brand-heavy

MARK CHUBB, MD PHD — brand share 50.0%
Specialty average (est.)

50% brand-name claims vs 50% generic, on 24 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

24
Total Claims
$7K
Total Drug Cost
N/A
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
24
Total Day Supply
720
Brand vs Generic
50% brand / 50% generic
Brand Drug Cost
$6K
Generic Drug Cost
$127

Patient Demographics

Average Patient Age
21.0 years
Avg HCC Risk Score
0.81

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

Drug Claims
Digoxin
12
Xarelto
Rivaroxaban
12

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Clinical Cardiac Electrophysiology Physician Overview

How MARK CHUBB, MD PHD fits within the Clinical Cardiac Electrophysiology Physician landscape nationally.

1,570
Clinical Cardiac Electrophysiology Physician Providers in US
52
States with Clinical Cardiac Electrophysiology Physician
1,596
Avg Claims per Provider

MARK CHUBB, MD PHD's 24 claims are below the specialty average of 1,596.

Nearby Clinical Cardiac Electrophysiology Physician Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as CHUBB.

Compare Clinical Cardiac Electrophysiology Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is MARK CHUBB, MD PHD's specialty?
MARK CHUBB, MD PHD specializes in Clinical Cardiac Electrophysiology Physician and practices in PALO ALTO, California. Credentials: MD PHD.
How much does MARK CHUBB, MD PHD prescribe under Medicare Part D?
In 2023, MARK CHUBB, MD PHD wrote 24 Medicare Part D claims totaling $7K in drug costs for N/A beneficiaries.
Where is MARK CHUBB, MD PHD located?
MARK CHUBB, MD PHD is located at 725 WELCH RD, PALO ALTO, CA, 94304. Phone: (650) 497-8000.
What is MARK CHUBB, MD PHD's NPI number?
MARK CHUBB, MD PHD's National Provider Identifier (NPI) is 1811542723, issued on 08/07/2019.
Does MARK CHUBB, MD PHD prescribe more brand-name or generic drugs?
MARK CHUBB, MD PHD's prescribing is 50% brand-name and 50% generic drugs by claim count, with $6K in brand drug costs.
How many Clinical Cardiac Electrophysiology Physician providers are there in the US?
There are 1,570 Clinical Cardiac Electrophysiology Physician providers across 52 states in the US. The average Clinical Cardiac Electrophysiology Physician provider writes 1,596 Medicare Part D claims per year.
What drugs does MARK CHUBB, MD PHD prescribe most often?
Based on 2023 Medicare Part D data, MARK CHUBB, MD PHD's most frequently prescribed drugs include Digoxin, Xarelto. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does MARK CHUBB, MD PHD accept Medicare?
MARK CHUBB, MD PHD appears in CMS Medicare data with 24 Part D claims and N/A Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify MARK CHUBB, MD PHD's credentials?
MARK CHUBB, MD PHD's NPI is 1811542723 with credentials MD PHD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology