Name: Dr. Thieu Nguyen

Specialty: Adult Congenital Heart Disease (ACHD) & Cardiology

Qualification / Board Certification: MD — Board Certified by the American Board of Internal Medicine

Affiliation(s): Memorial Hermann Memorial City Medical Center (Castle Connolly Top Hospital) | Memorial Hermann Sugar Land Hospital — Houston, TX

Locations (City/State): Houston, TX

Languages Spoken: English, Spanish, Vietnamese

Accepting New Patients: Yes

NPI Number: 1609967165

About the Doctor

Dr. Thieu Nguyen, MD is a highly specialized, board-certified Adult Congenital Heart Disease Specialist and Cardiologist serving patients in Houston, Texas. He completed his medical education at Texas Tech University Health Sciences Center School of Medicine — also cross-referenced with the University of Texas Medical School at Houston — and pursued rigorous postgraduate training through dual residency programs: Internal Medicine at the University of Texas Medical School at Houston, and Cardiovascular Diseases at the University of Texas Medical School in San Antonio. This dual-institution training in both internal medicine and cardiovascular subspecialty care provides Dr. Nguyen with an exceptionally comprehensive foundation in cardiac medicine.

Adult Congenital Heart Disease is among the most specialized and complex fields in cardiology. Adults born with structural heart defects — such as atrial septal defects, ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries — require lifelong, expert cardiac monitoring and management because even surgically repaired congenital defects can give rise to new complications over time, including arrhythmias, heart failure, pulmonary hypertension, and endocarditis. Dr. Nguyen’s ACHD specialization positions him as one of a relatively small number of cardiologists nationally who are specifically trained to navigate this highly technical intersection of congenital anatomy and acquired cardiovascular disease in adult patients.

Beyond congenital heart care, Dr. Nguyen manages a broad range of general cardiovascular conditions including high blood pressure, coronary artery disease, angina, vascular disease, and cardiac pain — making him a comprehensive cardiac resource for adult patients across Houston’s diverse communities. His trilingual fluency in English, Spanish, and Vietnamese is a significant clinical asset in Houston — one of the most ethnically diverse cities in the United States — ensuring that patients can discuss complex cardiac diagnoses and treatment decisions in the language they are most comfortable with.

Dr. Nguyen is affiliated with Memorial Hermann Memorial City Medical Center — a recognized Castle Connolly Top Hospital ranked for cancer surgery and additional procedures — and Memorial Hermann Sugar Land Hospital, providing his patients access to two respected Houston-area medical institutions. He is currently accepting new patients and welcomes both ACHD patients and those seeking general cardiology care.

Highlights at a glance:

• Specialist in Adult Congenital Heart Disease (ACHD) — a rare and highly specialized cardiology subspecialty
• Board Certified by the American Board of Internal Medicine
• Dual residency — Internal Medicine (UT Houston) and Cardiovascular Diseases (UT San Antonio)
• Medical degree from Texas Tech University Health Sciences Center School of Medicine
• Affiliated with Memorial Hermann Memorial City Medical Center (Castle Connolly Top Hospital)
• Trilingual — fluent in English, Spanish, and Vietnamese
• Accepts Medicare, UnitedHealthcare, CVS Health/Aetna, and other major plans
• Currently accepting new patients in Houston, TX

Education & Training

Dr. Nguyen’s academic and clinical training reflects a rigorous, multi-institution pathway through internal medicine and cardiovascular subspecialty training at respected Texas medical institutions:

• Medical School: Texas Tech University Health Sciences Center School of Medicine — (also cross-referenced with University of Texas Medical School at Houston, TX) (Doctor of Medicine — MD)
• Residency 1: Internal Medicine — University of Texas Medical School at Houston, Houston, TX
• Residency 2: Cardiovascular Diseases — University of Texas Medical School at San Antonio, San Antonio, TX
• Additional Program Training: Texas Tech University (Amarillo) Health Sciences Center Program
• Fellowship / Additional Training: Adult Congenital Heart Disease subspecialty training — management of structural cardiac defects, arrhythmias, heart failure, and pulmonary hypertension in adult patients with congenital heart conditions
• Board Certification: American Board of Internal Medicine (ABIM) — Active Certification in Cardiovascular Disease
• NPI Registration: Active — NPI Number 1609967165

Medical Conditions Treated

As an Adult Congenital Heart Disease Specialist and Cardiologist, Dr. Nguyen diagnoses, treats, and manages a comprehensive range of congenital and acquired cardiovascular conditions, including:

• Adult Congenital Heart Disease (ACHD) — All Structural Defect Types
• Atrial Septal Defect (ASD) & Ventricular Septal Defect (VSD) — Adult Management
• Tetralogy of Fallot — Long-Term Adult Follow-Up & Complication Management
• Transposition of the Great Arteries — Adult Post-Surgical Monitoring
• Pulmonary Stenosis & Aortic Stenosis in Congenital Patients
• Coronary Artery Disease (CAD) & Atherosclerosis
• Angina (Stable & Unstable) & Chest Pain Evaluation
• High Blood Pressure (Hypertension) & Hypertensive Heart Disease
• Vascular Disease — Peripheral Artery Disease & Vascular Insufficiency
• Heart Failure — Systolic & Diastolic (Including Congenital-Related)
• Arrhythmias — Atrial Fibrillation & Other Rhythm Disorders in ACHD Patients
• Pulmonary Hypertension — Including ACHD-Related Pulmonary Vascular Disease
• Endocarditis Risk Management & Prevention in Congenital Patients
• Cardiac Pain Evaluation & Management
• Cardiac Risk Assessment & Preventive Cardiovascular Care
• Post-Surgical Cardiac Monitoring for Repaired Congenital Defects

Medical Procedures Performed

Dr. Nguyen performs and coordinates a comprehensive range of cardiovascular diagnostic, interventional, and monitoring procedures, including:

• Catheter Placement & Cardiac Catheterization
• Echocardiography (Transthoracic & Transesophageal) — Cardiac Structure Assessment
• Electrocardiogram (EKG/ECG) — Rhythm & Electrical Function Monitoring
• Cardiac Stress Testing & Exercise Tolerance Evaluation
• Holter Monitor & Ambulatory Cardiac Rhythm Monitoring
• Blood Pressure Monitoring & Hypertension Assessment
• Vascular Disease Evaluation & Peripheral Circulation Assessment
• Congenital Heart Defect Structural Assessment & Long-Term Monitoring
• Cardiac Imaging Coordination — CT Angiography & Cardiac MRI
• Pulmonary Hypertension Evaluation & Management
• Anticoagulation Therapy Management for Cardiac Conditions
• Arrhythmia Evaluation & Electrophysiology Referral Coordination
• Heart Failure Assessment & Treatment Optimization
• Medical Examination & Cardiovascular Health Screening
• Specialist Referrals & Multidisciplinary Cardiac Care Coordination
• Telehealth Cardiac Consultations (availability — contact office to confirm)

Services Offered

Dr. Nguyen’s cardiology practice offers a distinctive and highly specialized range of cardiac care services, anchored in his exceptional expertise in Adult Congenital Heart Disease while extending to the full spectrum of general cardiovascular medicine. His trilingual practice environment and affiliation with Memorial Hermann Memorial City Medical Center — one of Houston’s premier medical institutions — ensure that his patients receive both world-class specialist care and the personal accessibility they deserve.

Adult Congenital Heart Disease (ACHD) Specialty Care Adult Congenital Heart Disease is the cornerstone of Dr. Nguyen’s practice and the area where his expertise is most uniquely valuable. As one of a relatively limited number of ACHD-trained specialists, he provides comprehensive lifelong cardiac management for adults who were born with structural heart defects — whether repaired in childhood or previously undetected. ACHD patients face a distinct set of risks and complications that require specialized knowledge far beyond general cardiology, and Dr. Nguyen’s dedicated training in this subspecialty positions him as an essential resource for this medically complex patient population in the Houston area.

• Comprehensive ACHD evaluation and long-term structural cardiac monitoring
• Management of repaired and unrepaired congenital heart defects in adults
• Monitoring for late complications — arrhythmias, heart failure, and pulmonary hypertension
• Endocarditis prophylaxis and risk management for congenital patients
• Coordination with cardiac surgeons and electrophysiologists for complex ACHD cases
• Transition of care support for young adults moving from pediatric to adult cardiac care

General Cardiology & Cardiovascular Disease Management In addition to his ACHD specialty, Dr. Nguyen provides broad general cardiology services for adult patients with acquired cardiovascular conditions. He evaluates and manages coronary artery disease, hypertension, angina, vascular disease, and cardiac pain — offering comprehensive cardiovascular care for patients across the Houston community.

• Coronary artery disease evaluation, risk stratification, and management
• Hypertension diagnosis, monitoring, and medication management
• Angina evaluation — stable, unstable, and variant presentations
• Vascular disease assessment and peripheral circulation management
• Chest pain and cardiac pain evaluation and workup
• Cardiovascular risk reduction counseling — lifestyle, diet, and medication

Cardiac Catheterization & Interventional Procedures Dr. Nguyen performs catheter placement and cardiac catheterization — an essential diagnostic and interventional tool in both congenital and acquired heart disease. Catheterization allows direct measurement of cardiac pressures, assessment of structural defects, and therapeutic interventions in carefully selected patients.

• Cardiac catheterization for hemodynamic assessment
• Catheter placement and vascular access procedures
• Pressure measurement in ACHD patients — pulmonary artery, ventricular, and aortic pressures
• Coordination of interventional cardiology procedures when needed

Heart Failure Management Dr. Nguyen manages heart failure in both congenital and acquired cardiac disease contexts, providing individualized treatment plans that address the underlying etiology, optimize medications, and monitor for disease progression and decompensation.

• Heart failure evaluation — systolic and diastolic presentations
• Medication optimization — diuretics, ACE inhibitors, beta-blockers, and SGLT2 inhibitors
• Fluid management and monitoring
• Coordination with advanced heart failure specialists for complex cases

Pulmonary Hypertension Management Pulmonary hypertension is a significant complication in many ACHD patients — particularly those with unrepaired or late-repaired defects — and also occurs as an acquired condition. Dr. Nguyen provides expert evaluation and management of pulmonary hypertension, coordinating advanced therapies when indicated.

• Pulmonary hypertension evaluation and pressure assessment
• Vasodilatory therapy consultation and management
• Long-term monitoring and disease progression tracking
• Coordination with pulmonary hypertension specialists

Trilingual Care — English, Spanish & Vietnamese Dr. Nguyen and his clinical team provide complete consultations and patient education in English, Spanish, and Vietnamese — ensuring that patients from Houston’s large Hispanic and Vietnamese-American communities can discuss their cardiac health in the language they are most comfortable with. For complex, life-altering conditions like congenital heart disease, this linguistic accessibility can meaningfully improve patient understanding, adherence, and outcomes.

• Full cardiac consultations in English, Spanish, and Vietnamese
• Culturally sensitive cardiac care for diverse Houston communities
• Patient education in preferred language — diagnosis, treatment, and follow-up instructions

Telehealth & Online Consultations Patients interested in virtual cardiology consultations are encouraged to contact Dr. Nguyen’s office directly at (713) 272-9022 to confirm telehealth availability and appropriate scheduling for virtual cardiac care visits.

Accepted Insurances

Dr. Nguyen accepts most major insurance plans. Patients are advised to call (713) 272-9022 before scheduling to verify their specific plan and network coverage. Accepted carriers include:

• Medicare
• UnitedHealthcare
• CVS Health (formerly Aetna)
• Health Care Service Corporation (HCSC)
• Community Health Choice
• Integranet Health
• Sentara Health System / Optima Health
• Crown Cork and Seal Company
• All Other Third Party Insurance Plans
• Other Health Care Provider Plans

Practice Locations

Location 1 — Primary Office Address: 7500 Beechnut St, Suite 291, Houston, TX 77074

Phone: (713) 272-9022

Hospital Affiliations

Dr. Nguyen holds admitting privileges at two Memorial Hermann hospitals serving the greater Houston area, including one recognized as a Castle Connolly Top Hospital:

• Memorial Hermann Memorial City Medical Center — Houston, TX (Castle Connolly Top Hospital — Ranked for Cancer Surgery & 2 Additional Procedures; a major full-service medical center serving west Houston and one of the flagship facilities of the Memorial Hermann Health System)
• Memorial Hermann Sugar Land Hospital — Sugar Land, TX (Houston area) (Full-service community hospital serving the Sugar Land and southwest Houston communities as part of the Memorial Hermann Health System)