Former U.S. Homeland Security Secretary Tom Ridge remains in an intensive care unit following a heart attack and emergency procedure last week, but his family is "cautiously optimistic" as he continues to make progress, according to a spokesperson for Ridge.The 72-year-old Ridge, a former two-term Republican Pennsylvania governor, remains hospitalized in Austin, Texas, where he was attending a Republican Governors Association conference.Tom Ridge was at his hotel when he called for help Thursday morning. His wife said first responders worked "heroically" to get her husband to the trauma center at Dell Seton Medical Center at the University of Texas.Ridge underwent a cardiac catheterization. Since then, some of the assistive machines used to keep him stable have been removed.“We are cautiously optimistic that Tom can make a full recovery,” said his wife andformer Pennsylvania First Lady, Michele Ridge. “Doctors are encouraged by hisprogress and so are we – even though we realize there’s still a long road ahead."Ridge, a U.S. Army veteran of the Vietnam War, also was a county prosecutor and a six-term congressman from Erie, Pennsylvania, before being elected the state's governor in 1994.Ridge was the nation's first homeland security secretary, serving under Republican President George W. Bush until February 2005. He left the governorship after the terrorist attacks of Sept. 11, 2001, to join the Bush administration.Since leaving government, Ridge has headed Ridge Global, a firm that advises on cyber security, international security and risk management.Ridge and his wife live in Bethesda, Maryland.The Associated Press contributed to this report.