Dr. Mark A. Jr

David S. Harper, M.D., F.A.C.C. practices general and invasive cardiology with Presbyterian Heart & Vascular Group, and is board-certified in internal medicine and cardiovascular diseases. After receiving his undergraduate degree from Duke University in Durham, N.C., Dr. Harper attended medical school at The University of Texas Southwestern Medical School in Dallas, where he also completed his internship and residency. He then completed his cardiology fellowship at Wake Forest University Baptist Medical Center in Winston-Salem, N.C.Dr. Harper participates actively in the internal medicine teaching program at Texas Health Presbyterian Hospital Dallas, and is a Fellow of the American College of Cardiology. His areas of expertise include preventive cardiology, echocardiography, valvular heart disease, coronary artery disease, nuclear cardiology and heart rhythm management. Dr. Harper and his wife Courtney have four children. Dr. Harper is rated as a Distinguished provider by MediFind in the treatment of Fainting. His top areas of expertise are Aortic Regurgitation, Pediatric Myocarditis, Necrosis, and Atrial Fibrillation.

"Shirley Ann Williams, M.D., was born in Peoria, Ill. Raised in a family with 12 children, she received her B.S. in Biology from Peoria's Bradley University, where she graduated cum laude. After completing medical school in 1977 at the University of Iowa School of Medicine, Iowa City, Iowa, Williams continued her education at the Cleveland Clinic Foundation in Cleveland, Ohio, where she completed a residency in internal medicine and a fellowship in noninvasive cardiology.Upon completion of her formal medical training, Williams became a staff cardiologist at the Veterans Administration Center in Temple, Texas. While there, she also served as assistant professor in the Department of Medicine at the Texas A&M University College of Medicine. These experiences inspired Williams to expand her skills by pursuing an additional fellowship in invasive cardiology at Hahnemann University Hospital in Philadelphia, Pa., in 1990. Prior to her move to Dallas, she was in private practice in Macon, Ga., for 4 1/2 years. A Fellow of the American College of Cardiology, Williams is board-certified by the American Board of Internal Medicine (ABIM), and the ABIM Subspecialty Board of Cardiovascular Diseases.In 2011, Williams was nominated as ""Cardiologist of the Year"" for Denton County. She serves as medical director and chairman of the quality improvement committee and utilization review committee at Lewisville Medical Center, where she is also a member of the leadership team and serves as secretary of the medical staff. Williams is also a member the hospital's critical care committee and open heart committee. She received the Thomas F. Frist humanitarian award from Lewisville Medical Center in April 2011. Williams also serves on the HCA North Texas Division physician quality advisory committee for the nine north Texas hospitals.Williams holds active medical staff privileges at Texas Health Flower Mound, Lewisville Medical Center and Texas Health Denton.Williams joined Cardiovascular Specialists P.A. in April, 1995. One of her strengths is an ability to relate to different kinds of people much of which she attributes to growing up with so many siblings. She also has a special fondness for the elderly, and counts her experiences in caring for older patients as some of her most rewarding.". Dr. Williams is rated as a Distinguished provider by MediFind in the treatment of Fainting. Her top areas of expertise are Orthostatic Hypotension, Glucocorticoid-Remediable Aldosteronism, Hypertension, and Pediatric Myocarditis.

Mark Sij is a primary care provider, practicing in Internal Medicine in Kaufman, Texas. Dr. Sij is rated as an Advanced provider by MediFind in the treatment of Fainting. His top areas of expertise are Hypertension, Familial Hypertension, Glucocorticoid-Remediable Aldosteronism, Inappropriate Sinus Tachycardia (IST), and Hip Replacement.