Dr. David Marr Medical Director, Saint John area Dr. David Marr has served as the Medical Director of the Saint John area for over a decade. A graduate of the University of New Brunswick, he completed his medical degree and residency training at Dalhousie University, specializing in internal medicine and cardiology, before joining the Horizon’s Saint John Regional Hospital in 1980. A Fellow of the Royal College of Physicians and Surgeons of Canada in Internal Medicine and Cardiology and the American College of Cardiology, Dr. Marr was instrumental in establishing the New Brunswick Heart Centre in 1991. Dr. Marr has held many leadership roles, including Chief of Internal Medicine, President of the Saint John Medical Society and the New Brunswick Medical Society, and has served on the Board of Directors of the Canadian Medical Association. In addition to his work as a staff cardiologist, he is also an Associate Professor of Medicine at both Dalhousie University and Memorial University.