B. John Memar
Founder & Chairman of the Board

John graduated from Georgia College and State University with a B.S. in Business Administration.  He has over 20 years experience in the healthcare industry.  He worked for Gwinnett Family Medicine as Practice Administrator for three years and spent four years at Medical Bureau, Inc., a medical billing service, as a Vice President before founding Medac in 1992.

Gregory R. Zinser
Chief Executive Officer

Greg comes to Medac with more than 30 years of experience in healthcare administration and finance.  His career began with Ernst & Young, where he provided auditing and consulting services to numerous hospitals and health care related organizations, before becoming Chief Financial Officer of Vista Hill, the western region’s largest provider of mental health and substance abuse services.  During a 12 year period as CFO, then VP of Business Development and VP of Operations, he directed a growth effort that took Vista Hill from a local provider with $28M in annual revenues to a multi-state organization with 18 entities and $55M in revenues.  He has experience in all facets of healthcare operations, including strategic planning, budgeting and risk management. He also has physician practice specific experience, including the creation of a licensed HMO, two physician independent practice associations (IPA’s), and design of physician risk sharing arrangements.   Greg became Chief Executive Officer of Vista Hill in 1997 and held that position for seven years before becoming President & CEO of TeamHealth Anesthesia Management, which provided a full range of management services to anesthesia groups throughout the U.S.  Most recently, He was President  & CEO of Anesthesia Management Professionals, the management company for ASMG, one of the nation’s largest anesthesia practices.