06/07/2010 at 01:00 AM EDT
Ally Smith sees herself in her taffeta gown, staring back in the mirror-and tears up. "I thought," she says, "this was never going to happen."
Just last year Ally, 22, was planning her funeral: A strep throat had led to a broader infection that left the Richmond, Texas, student in advanced heart failure. In an eight-hour surgery, doctors implanted a revolutionary new version of a life-saving heart pump. Miniaturized with a lightweight and extra-long-lasting battery pack, it has helped some 4,000 patients like Ally resume their lives; otherwise she might at best have been on a heart-transplant waiting list for years. "Without this," says Ally's physician Dr. Roberta Bogaev, "Ally would be dead. Now she has a great life."
While the former competitive swimmer can't go back in the pool (the tubing leading to the battery pack can't be submerged), Ally can do just about everything else-most important, march down the aisle June 26 in her gown and leather cowboy boots. "No one," says fiancé Mike Babineaux, 24, "can replace her."