Dr. Gregg S. Shander

Dr. William (Bill) Warren is a cardiologist specializing in non-invasive and imaging cardiology. He is board-certified in Internal Medicine, Cardiovascular Disease, Nuclear Cardiology, and Echocardiography. Dr. Warren graduated summa cum laude from Princeton University, earned his Doctor of Medicine degree at Harvard Medical School, completed his internal medicine internship and residency at Massachusetts General Hospital, and finished a cardiology fellowship at Johns Hopkins Hospital. His areas of focus include a wide range of cardiovascular conditions and treatments, with expertise in non-invasive diagnostic studies.Since joining The Chattanooga Heart Institute in 2003, Dr. Warren has become a valued leader at CHI Memorial and in the Chattanooga medical community. He currently serves as managing partner of The Chattanooga Heart Institute, where he collaborates with over 30 colleagues. He previously chaired the CHI Memorial Board of Directors.Dr. Warren possesses a broad range of clinical interests and expertise. His dedication to patient care stems from a deep love of science combined with a genuine ability to connect with patients on a personal level. The complexity and diverse treatment options within cardiovascular care drew him to this field, allowing him to help critically ill patients recover and thrive. He was the recipient of CHI Memorial’s inaugural St. Luke’s Healer’s Heart award which recognizes physicians and providers for demonstrating compassion, inclusion, integrity, excellence and collaboration.Dr. Warren's commitment extends beyond clinical practice. He has conducted research studies which have been published in prestigious journals including the American College of Cardiology Current Journal Review, Circulation, Journal of Infectious Diseases, Journal of Clinical Microbiology, and Journal of Clinical Research.Away from work, Dr. Warren enjoys nature photography and travel. He has visited all seven continents. Dr. Warren is rated as a Distinguished provider by MediFind in the treatment of Hypertension. His top areas of expertise are Coronary Heart Disease, Atherosclerosis, Angina, Pacemaker Implantation, and Heart Bypass Surgery.

Dr. William F. Oellerich earned his medical degree from the University of Tennessee at Memphis while concurrently earning a doctorate in philosophy in its Department of Pharmacology. He completed his internship and residency in internal medicine and served as chief resident at Barnes-Jewish Hospital at the Washington University School of Medicine in St. Louis, Missouri. He also completed his fellowship in cardiology at Washington University School of Medicine.Dr. Oellerich is board certified in cardiology and echocardiography. He has had specialized training in nuclear cardiology, diagnostic cardiac catheterization, cardiac magnetic resonance imaging, autonomic pharmacology, cardiovascular pharmacology, and echocardiography. He has been published in the American Journal of Roentgenology, Neuroscience and The Journal of Pharmacology and Experimental Therapeutics.He is the director of the echocardiography lab and CT cardiovascular program at Memorial Hospital. He plays an instrumental part in the ongoing progress of the cardiovascular CT program. He is helping to coordinate the introduction of a valve clinic to The Chattanooga Heart Institute. Dr. Oellerich is rated as a Distinguished provider by MediFind in the treatment of Hypertension. His top areas of expertise are Coronary Heart Disease, Atherosclerosis, Aortic Valve Stenosis, and Angina.

Dr. Allen Atchley is board certified in Internal Medicine and Cardiovascular Diseases and also holds specialized board certifications in Echocardiography, Nuclear Cardiology and is a Registered Physician in Vascular Interpretation, Vascular Ultrasound. He completed his fellowship in cardiology at Duke University Medical Center where he further pursued advanced training with a specialized fellowship in non-invasive cardiovascular imaging. Dr. Atchley also completed his internship and residency in Internal Medicine at Duke.Dr. Atchley performed the first 3D Transesophageal Echo (TEE) in Chattanooga in March of 2011 and is one of only a few cardiologists level 3 trained in echocardiography and nuclear cardiography in the area. While at Duke University, he participated in research focused on echo and nuclear cardiology.Dr. Atchley and his wife have four young children—twin girls, a daughter one year younger and the youngest, a son. His leisure time is spent enjoying activities with his family. Dr. Atchley is a former All-American golfer. Dr. Atchley is rated as a Distinguished provider by MediFind in the treatment of Hypertension. His top areas of expertise are Mitral Valve Regurgitation, Coronary Heart Disease, Atherosclerosis, Heart Bypass Surgery, and Pacemaker Implantation.