Find a Top Internist Near Me in Diamond Bar, CA – Book an Appointment Instantly

Wasim H. Raja, MD, is proud to be the primary care provider of choice for many families in and around Anaheim, Huntington Beach, Santa Ana, Garden Grove, Irvine, and Newport Beach at his practice in Fountain Valley, California. He has earned a reputation for excellence through his attention to detail and unrushed, customized approach to health care. 

Dr. Raja earned his medical degree at Allama Iqbal Medical College in Lahore, Pakistan, in 1998. He went on to complete a residency through the SUNY Health Science Center in Brooklyn, New York.

After more than two decades of treating patients in clinics, hospitals, emergency rooms, intensive care units, and nursing home, Dr. Raja has an expansive body of experience. He is also skilled in telemedicine services. 

As a board-certified internal medicine specialist, Dr. Raja sought out and completed additional education and training to expand his skill set. He is also a proud member of the American College of Physicians. 

A firm believer in the power of personalized care, Dr. Raja takes the time to get to know his patients and their needs. He builds patient education into every interaction, empowering those in his care to take charge of their own unique health journeys. He also speaks English, Urdu, and Punjabi, and enjoys caring for patients of all backgrounds.  

Dr. Raja embraces a holistic approach to health care, recognizing and honoring the connections between body, mind, community, and spirit. While he delivers care solidly rooted in science, Dr. Raja also understands the value of traditional medicine and supports patients who want to integrate alternative care into their health planning. 

For those in the Fountain Valley, California, as well as surrounding areas, who are searching for outstanding primary care and family medicine specialist, taking the time to come in and meet Dr. Raja and his team is a worthy endeavor. Booking takes just moments online or over the phone.

Yasir Shareef is a physician, a community builder, and social activist.

He graduated from the University of Michigan with Bachelor’s and Master’s Degrees.

He then attended Michigan State University for his medical education. Dr. Shareef currently practices as a neurologist in Arizona.

He is the director of stroke and neurology at Mountain Vista Medical Center in metropolitan Phoenix area.

He is also a mentor and clinical faculty to medical students at Midwestern University.

He has been with CAIR-AZ since 2011 and has helped revamp the organization into the respected civil rights organization that it is today.

Brett Wertman, MD, FACC, is a triple board-certified cardiologist who is widely respected for his treatment and care for patients at Coastal Cardiology of Orange County in Ladera Ranch and Irvine, California.

Dr. Wertman, who twice has been named a Physician of Excellence by the Orange County Medical Association, also leads the Cardiac Rehabilitation Program at Hoag Hospital Irvine in Irvine. 

An Orange County native, Dr. Wertman graduated summa cum laude and with Phi Beta Kappa Society honors in earning his Bachelor of Arts degrees in biochemistry and molecular, cellular, and developmental biology from the University of Colorado Boulder in Boulder, Colorado.

Dr. Wertman then completed his medical degree from the University of Washington in Seattle, Washington, and went on to finish his internship and residency training in internal medicine at Ronald Reagan UCLA Medical Center in Los Angeles, California.

He completed his fellowship training in cardiology and interventional cardiology at Cedars-Sinai Medical Center, also in Los Angeles.

Dr. Wertman has authored numerous publications in leading peer-reviewed journals and participated in live case transmissions to national meetings, demonstrating new techniques in the treatment of coronary artery disease and valvular heart disease. 

Dr. Wertman is highly trained in the percutaneous treatment of valvular heart disease, including aortic valve replacement using the Edwards Sapien heart valve system, as well as mitral valve repair using the Abbott MitraClip™ system. He also has significant experience in other novel interventional therapies.

He looks forward to welcoming new patients and offering superior care to those returning to Coastal Cardiology of Orange County.

In Dr. Wertman’s spare time, he enjoys relaxing with his family, traveling, and exercising.

Huy Nguyen, MD, FACC, a cardiologist at Coastal Cardiology of Orange County, has deep roots in Irvine, California, one of the communities the practice proudly serves, along with Ladera Ranch, California.

Dr. Nguyen grew up in Irvine and received his Bachelor of Arts in biology from the University of California, Irvine. 

He then earned a master's in applied physiology and earned his medical degree from Chicago Medical School, one of the graduate schools of the Rosalind Franklin University of Medicine and Science in North Chicago, Illinois. 

Back in Orange County, he completed his internship and residency in internal medicine, as well as his fellowship training in general cardiology, all at UC Irvine Medical Center in Orange, California.

He then moved to New York to complete his interventional cardiology fellowship at Mount Sinai Hospital in New York City, where he was awarded Outstanding Interventional Cardiology Fellow of the Year.

Throughout the course of his training, Dr. Nguyen has given numerous lectures and presentations, and has authored publications in peer-reviewed journals on various topics in both general and interventional cardiology.  

He was involved with and participated in live case demonstrations at Mount Sinai Hospital, focusing on complex coronary interventions.

Dr. Nguyen believes in a patient-centric approach to cardiovascular care and focuses on the collaborative efforts with his patients in optimizing their outcomes.

In his spare time, Dr. Nguyen enjoys spending time with his family, watching movies, playing basketball, and surfing.

Teferi Mitiku, MD, FACC, is a board-certified cardiologist in Clinical Cardiac Electrophysiology and Cardiovascular Disease. He specializes in cardiac electrophysiology (EP) and provides the entire spectrum of arrhythmia treatments, including medical therapy, catheter ablation, and device-based therapy. Dr. Mitiku strives to provide compassionate care for his patients at Coastal Cardiology of Orange County in Irvine and Ladera Ranch, California.

Dr. Mitiku earned his Bachelor of Science in molecular cell and development biology from the University of California, Los Angeles (UCLA), graduating magna cum laude. He went on to attend the David Geffen School of Medicine at UCLA, receiving his Doctor of Medicine. 

He then completed his internship and residency in internal medicine at Stanford University Hospital in Stanford, California, before completing cardiovascular medicine and electrophysiology fellowships at Yale New Haven Hospital in New Haven, Connecticut.

He previously served as the Director of Electrophysiology and an Assistant Professor of Medicine in the Division of Cardiology at the University of California, Irvine (UCI) School of Medicine and Wayne State University School of Medicine.

During his academic appointments, Dr. Mitiku enjoys teaching medical students, residents, and cardiology fellows. He was awarded Outstanding Teacher of The Year for three consecutive years and was granted entry into the Gold Humanism Honor Society.

Dr. Mitiku is affiliated with UCI Medical Center in Orange, California, and serves as the director of electrophysiology at Hoag Irvine Hospital in Irvine, California. At Hoag, He was awarded the top quality performer within the Cardiology peer group for 2019 and 2020. He is also a member of the American Heart Association, American College of Cardiology, and the American Medical Association.

He looks forward to welcoming new patients and providing excellent care for those continuing at Coastal Cardiology of Orange County.

Mahmoud Eslami-Farsani, MD, FACC, FSCAI, is a board-certified cardiologist at Cardiology Specialists of Orange County in Santa Ana, Irvine, and Newport Beach, California. He has special interests in coronary intervention, including angioplasty, stent placement, valvuloplasty, valvular heart disease, and peripheral vascular intervention. 

Dr. Eslami-Farsani earned his medical degree from Hahnemann University in Philadelphia, Pennsylvania. He then completed his internship and residency at the University of California, Irvine Medical Center in Orange, California, before completing his interventional and cardiology fellowships at the University of Southern California in Los Angeles.

He holds board-certifications in cardiovascular disease, interventional cardiology, and internal medicine. To remain up-to-date on the latest developments in his field, Dr. Eslami-Farsani is a member of the American College of Cardiology, the American Medical Association, and the American College of Physicians. 

Dr. Eslami-Farsani is currently welcoming new patients and looks forward to partnering with them. Schedule an appointment with Dr. Eslami-Farsani by calling the office or booking online today.

Ali Ashtiani, MD is a fellowship-trained, board-eligible interventional cardiologist at Cardiology Specialists of Orange County (CSOC) practicing in Santa Ana, Irvine, and Newport Beach, California. He has special interests in coronary intervention including coronary angioplasty & stent placement, pacemaker implantation, and valvular/structural heart disease.

Dr. Ashtiani received his medical training in our very own Orange County. After earning his medical degree from the University of California, Irvine Medical Center in Orange, California, he went on to complete internal medicine internship and residency followed by cardiology fellowship and advanced fellowship training in interventional cardiology at the same institution.


Dr. Ashtiani is affiliated with Hoag Hospital Heart and Vascular Institute in Newport Beach, Hoag Hospital Irvine, & Hoag Orthopedic Institute, St. Joseph Hospital in Orange, and Orange County Global Medical Center in Santa Ana.

Dr. Ashtiani is currently welcoming new patients and looks forward to providing individualized care with patience and compassion just as he would treat his own family. Schedule an appointment with Dr. Ashtiani by contacting our office today.

Board-certified cardiologist Ethan Yalvac, MD, FACC, FSCAI, RPVI, CBNC, is proud to provide comprehensive care to patients at Cardiology Specialists of Orange County in Santa Ana, Irvine, and Newport Beach, California.

Dr. Yalvac received his Bachelor of Arts in economics and math, graduating cum laude. He earned his Doctor of Medicine from the University of Texas Medical Branch School of Medicine in Galveston. He then completed his internship and residency in internal medicine at Tulane University in New Orleans, Louisiana. Afterward, Dr. Yalvac completed a general cardiology fellowship at the Tulane University Heart and Vascular Institute before completing an interventional cardiology fellowship at the University of California, San Diego. 

He holds certification from the Board of Nuclear Cardiology in advanced cardiac life support and is Level II trained in echocardiography. Dr. Yalvac is a member of the Society for Vascular Ultrasound, and a fellow of the American College of Cardiology and the Society for Cardiovascular Angiography and Interventions.

Dr. Yalvac is affiliated with Hoag Hospital and Hoag Vascular Institute in Newport Beach, Hoag Hospital & Orthopedic Institute in Irvine, St. Joseph Hospital in Orange, and Orange County Medical Center in Santa Ana, California.

At Advanced Cardiovascular Care, Inc., we believe the best heart health combines medical expertise, state of the art technology, and most importantly personalized, compassionate care.

With convenient locations, our staff serves the Inland Empire of Southern California including: San Bernadino, Redlands, Loma Linda, Banning, Beaumont, Riverside, Moreno Valley, Perris, Murrieta, Temecula, Corona, Norco, Eastvale, Lake Arrowhead, Big Bear, and Victorville.

Since 2005 our patients have enjoyed excellent heart and vascular care based on our philosophy of using the latest and most advanced medical knowledge and skill, technology, and genuine concern to help you enjoy life. Don't just live life, love it.

We provide individualized, personal care at its best

When it comes to your heart care, you want a practice that takes the time to get to know you better and make sure that you are completely comfortable with the care you receive. You need a cardiologist who along with his staff would not only provide you with the latest knowledge but also be adept with the most recent technical skills required to take the best care of you as an individual. Our cardiologists are energetic, passionate, and dedicated individuals who are also highly trained not only in the heart but also vascular diseases and interventions.

We have always practiced cardiology with one question in our minds … If we were the patient, how would we want to be treated? The answer is that we would want to be treated with personal, affectionate care, putting our needs first, offering us a healthy heart with a good quality of life. So that is how you can expect to be treated at our office. We love to interact with our patients and provide them with the compassionate and personalized care, individualized to their needs, for their most vital aspect of their lives: their heart.

Our Mission

To provide safe, high quality, personalized, compassionate and cost-effective healthcare services resulting in excellent patient outcomes

Our Vision

To be the leader in the community providing par excellence heart and vascular care to our patients utilizing evidence-based medicine and the latest fund of knowledge.

Our Values

• We strive to uphold an exceptional level of personalized service delivered with the utmost compassion and professionalism.
• We believe in an unwavering commitment to improving the treatment and lives of the patients we serve through the highest standards of clinical care.
• We believe in the empowerment of and investment in our employees to perform with absolute integrity, honesty, and reliability.

Yasir Shareef is a physician, a community builder, and social activist.

He graduated from the University of Michigan with Bachelor’s and Master’s Degrees.

He then attended Michigan State University for his medical education. Dr. Shareef currently practices as a neurologist in Arizona.

He is the director of stroke and neurology at Mountain Vista Medical Center in metropolitan Phoenix area.

He is also a mentor and clinical faculty to medical students at Midwestern University.

He has been with CAIR-AZ since 2011 and has helped revamp the organization into the respected civil rights organization that it is today.

The office of Melanchton A. Mangoba, MD, offers comprehensive internal medicine services to the Riverside, California, community. The health care team specializes in diagnosing and treating a variety of acute and chronic diseases in adults. They also focus on preventive health services and annual wellness exams to reduce risk factors for long-term health complications through individually tailored Healthy Plans.

As a board-certified internal medicine physician, Dr. Mangoba provides primary care services to manage hypertension, renal failure, diabetes, and other chronic diseases. He and his team also focus on the specialized needs of geriatric patients. They diagnose and treat conditions like dementia with respect and dignity.

The office of Melanchton A. Mangoba, MD, has the latest diagnostic testing technologies to give patients answers to their health questions as soon as possible. The team takes a patient-focused approach to health care and provides preventive resources to support long-term health and wellness. Dr. Mangoba strives to provide the highest quality of patient care and enjoys building a strong foundation for patient-physician relationships.

If you’re looking for a compassionate internal medicine physician, schedule an evaluation online or by calling Melanchton A. Mangoba, MD, today.

Dr. Daniel Brelian is a gastroenterologist at Downtown Gastro Medical Group in Los Angeles. He is board-certified in Internal Medicine and Gastroenterology, and is passionate about helping patients recover from a wide range of digestive ailments and conditions.

Dr. Brelian received his bachelor’s degree in Molecular and Cell Biology from the University of California, Berkeley and went on to earn his Doctor of Medicine at Drexel University College of Medicine in Philadelphia.

He has worked in some of the most innovative and prestigious medical centers in the nation, including Cedars-Sinai Medical Center, Georgetown University Hospital, and New York University. Before opening his private practice, he was a physician at the Pacific Alliance Medical Group.

Dr. Brelian’s work has appeared in numerous medical journals, including Gastroenterology and Gastrointestinal Endoscopy. Committed to the latest research and training, he is also a member of many professional organizations, including the American College of Gastroenterology (ACG) and the American Gastroenterological Association (AGA).

At Downtown Gastro Medical Group, Dr. Brelian helps patients recover from conditions like irritable bowel syndrome, food allergies, acid reflux disease, Crohn's disease, and more. With a commitment to the most excellent quality of patient care, his patients feel supported and empowered to live their healthiest lives.

Qais Ayouby, MD, is an accomplished internal medicine specialist practicing at Alertive Healthcare Medical Group in Riverside, California. At the practice, he provides patients with compassionate and effective care. 

Dr. Ayouby completed his medical degree with honors in 2016 and has since accrued more than seven years of diverse medical experience. He has an impressive track record in the field of internal medicine and is well-regarded among his peers and patients alike. 

Dr. Ayouby is affiliated with several hospitals in the region, including Corona Regional Medical Center and Temecula Valley Hospital in California. He also collaborates with many other doctors and specialists in various medical groups, demonstrating his commitment to providing comprehensive patient care. 

In addition to his professional achievements, Dr. Ayouby enjoys spending his free time reading and being with his family. He recently became a father to a little girl, which has brought him immeasurable joy and fulfillment. 

Dr. Ayouby's patients appreciate his compassionate approach and ability to build strong, trusting relationships. He is dedicated to staying up-to-date with the latest advancements in internal medicine and actively seeks new professional development opportunities. Dr. Ayouby is skilled, respected, and committed to delivering the highest quality care to his patients. 

Raised in Glendale, CA, Dr. Derhartunian has always had a passion for medicine.  Growing up in the tight community, he spent most of his childhood helping his father at a local pharmacy.  There, he not only learned a vast array of different pharmacokinetics, but also strengthened the bond with the community in which he dreamed of serving.  Dr. Derhartunian's career began in Glendale at R.D. White Elementary School where him and Dr. Tovmassian became instant friends.  He then went on to complete his education at Woodrow Wilson Middle School followed by Glendale Senior High School.  After obtaining a Bachelors in Science in Biochemistry from the University of California at Santa Barbara, Dr. Derhartunian attended Ross University Medical School.  He completed Internal Medicine Residency at NYU-Lutheran Medical Center in Brooklyn, NY.  His main focus in medicine is a preventative approach with a focus on evidence based medicine.

At Elevate Health Group, Dr. Narbeh Tovmassian is a leading provider of general health and preventative medicine. The practice provides Glendale, CA patients with services such as comprehensive, annual physicals, chronic and complex medical treatment and management, inpatient hospital services, nursing home visits, well-person visits, preoperative medical exams and checkups, sports physicals and injury treatment, STD screenings, vaccinations, and so much more.

Dr. Tovmassian grew up in Glendale and has been devoted to medicine from a young age. He obtained his Bachelor’s degree in Physiological Sciences at the University of California- Los Angeles. Dr. Tovmassian went on to receive his Doctorate of Medicine from the Ross University’s School of Medicine. He also completed a three-year Internal Medicine residency in Las Vegas at the University of Nevada’s School of Medicine. He is also board certified by the American Board of Internal Medicine. He specializes in preventative medicine and cardiovascular diseases.

His expertise lies in the diagnosis, treatment, and prolonged care of adults ranging from general health to complex conditions and illnesses. The practice focuses on a patient-oriented approach and Dr. Tovmassian aims to provide the highest quality care to his each and every one of his patients. The practice is also devoted to utilizing the most recent innovations in the medical field.

Elevate Health Group is dedicated to upholding the principles of a traditional internal medicine practice and works to provide patients with continuing care from an expertly trained physician. Dr. Tovmassian works to ensure that his patients feel welcomed, comfortable, and in capable hands.

Dr. Tovmassian and the entire staff of Elevate Health Group welcome new patients, where the practice accepts most major forms of medical insurance.