Nwankwo was diagnosed with hypertrophic cardiomayopathy, or an enlarged heart. He will no longer be able to play basketball.
Nwankwo collapsed about 15 minutes into practice, and a call was placed to 911 "within 20 seconds," according to Meyer.
Meyer felt no pulse when he rushed to Nwankwo.
"My instincts kicked in," Meyer said. "It is such a surreal feeling. I've run codes before, but whenever it is one of your own, per se, it is a lot different. My instincts took over and I did what I was expected to do."
Meyer used the AED and administered two rescue breaths before Nwankwo began breathing on his own.
"The quick actions of Mike Meyer, the emergency responders and the Vanderbilt health care providers saved this young man's life," said Andrew Gregory, the team's physician.
Meyer said the emergency responders arrived quickly, though he had a moment of panic.
"There was one time I looked up and thought, 'Where are they?'" Meyer said. "When I did that, they were walking through the door."
Nwankwo was responding to verbal commands but unable to talk when he was taken to the hospital.
"I knew when they wheeled him off he was stabilized," Meyer said. "It was a huge relief but we knew we were not out of the woods by any means."
Nwankwo was released from the hospital on Thursday.
"While we are extremely disappointed that this means the end of Davis' playing career, we're very grateful that the prognosis for the rest of his life is good," coach Kevin Stallings said in a statement. "Mike Meyer is truly a hero."
Nwankwo's father Adam thanked Meyer in a statement:
"Davis is alive today all because of trainer Mike Meyer," Adam Nwankwo said. "There really are no words or anything that we can do to thank him enough."
Vanderbilt forward Davis Nwankwo sits on the bench during a game against Auburn, during the 2006 Southeastern Conference basketball tournament, Thursday, March 9, 2006, at the Gaylord Entertainment Center in Nashville, Tenn. Nwankwo was released from the hospital Thursday after collapsing at practice Monday. Doctors say he won't play basketball again because of an enlarged heart. (AP Photo/John Bazemore)