Margarita Ontiveros, MD

Medicare activity in 2024

Official CMS public-use data for Margarita Ontiveros, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Most frequent services

1. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)251 services
2. Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report (93000)242 services
3. Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)85 services
4. Injection, regadenoson, 0.1 mg (J2785)72 services
5. Ultrasound of heart with color-depicted blood flow, rate, direction and valve function (93306)49 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

• High blood pressure75%
• High cholesterol75%
• Ischemic heart disease51%
• Diabetes50%
• Arthritis46%
• Chronic kidney disease44%

Practice locations

Addresses where Margarita Ontiveros is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 6; the Medicare profile lists all.

• 1200 Brooklyn Ave, Suite 120San Antonio, TX 78212 (210) 271‑7266
• 3154 SE Military Dr, D101San Antonio, TX 78223 (210) 281‑9800
• 3922 Wiseman Blvd, Bldg IISan Antonio, TX 78251 (210) 281‑9800
• 6800 I 10, Suite 100San Antonio, TX 78201 (210) 575‑8289
• 6800 W Ih, 10 Suite 130San Antonio, TX 78201 (210) 932‑1487

Group practices

Medicare enrollment lists Margarita Ontiveros as a member of this group (CMS data updated October 2, 2026).

• Methodist Physician Practices PLLC175 clinicians in the group

Specialties

• Cardiovascular Disease (Cardiology)primary

Find other Cardiovascular Disease (Cardiology) doctors in Texas →

Other cardiologists in San Antonio

Clinicians with the same Medicare primary specialty in San Antonio, TX — not a recommendation.

• Juan L. Garza, MD
• Shalin S. Patel, MD
• David L. Briseno, MD
• Jeffrey C. Fletcher, DO
• Erika Jones, MD
• John M. Erikson, MD
• Nawfal Mihyawi, MD
• Andrew Mackinnon

All cardiologists in San Antonio →

Other clinicians in Methodist Physician Practices PLLC

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

• James H. Prieto, MD
• Jamil A. Malik, MD
• Gary M. Hall, MD
• Ghassan Abusaid, MD
• Sabita Thapa, NP
• Rachel Rhodes, PA

Clinician information

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
2. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
4. Medicare Care Compare — official Medicare tool to look up clinicians