 He also did a fellowship in cardiothoracic surgery at Stanford Hospital.In 1985, Griepp succeeded Robert S. Litwak as Chief of the Division of Cardiothoracic Surgery at Mount Sinai Hospital.Under Griepp's direction, Cardiothoracic Surgery was made an independent department at both the Icahn School of Medicine at Mount Sinai and Mount Sinai Hospital, and Griepp was its first chairman.