"It is always in the back of your mind - that minute barrier sitting there," Gangloff said. "I've been knocking on the minute barrier for so long, it feels great breaking through it. I almost skipped 59."
Olympic teammate Eric Shanteau (Lilburn, Ga.) also swam his best time, taking home the silver in 59.45. Marcus Titus (Tucson, Ariz.) finished third in 1:00.00.
Elizabeth Pelton (Baltimore, Md.) took an early lead in the women's 200m IM, swimming under world record pace in the front half of the race. However, it was Olympian Smit who came back on the second half to stamp her ticket to Rome with an American record time of 2:09.34. In the race for second, Pelton out touched Ariana Kukors (Auburn, Wash.) with a time of 2:11.03. Kukors took third in 2:11.07.
"I definitely saw them on the back-to-breast turn," Smit said. "I just went out all at the end, and tried to come home fast enough. I'm so excited to break the record."
The men's 400m IM got the crowd on its feet, with Tyler Clary (Riverside, Calif.) and two-time Olympian Ryan Lochte (Daytona Beach, Fla.) batting for first. Clary was under Michael Phelps' world record pace when he turned on the back-to-breast leg. He continued to head up the heat until the final turn, when Lochte closed in and claimed the victory in 4:06.40.
"I'm glad that I got the first race out of the way," Lochte said. "I'm just going to take that energy and go from there. I was just going to swim my own race tonight. I knew he'd go out fast. At the end, it's every man for himself."
Clary shaved five seconds off his best time to earn silver in 4:06.96. Jack Brown (Atlanta, Ga.) hammered home seven seconds later to pick up the bronze in 4:13.71.
Olympian Christine Magnuson (Tinley Park, Ill.) scored the first gold of the five-day meet when she touched in first in the women's 100m butterfly in 57.16. The time is the third-fastest in the world this year. Dana Vollmer (Granbury, Texas), who competed in the 2004 Olympics, clocked her best time of 57.39 in the event to take second, and Stanford's Elaine Breeden (Lexington, Ky.), who competed with Magnuson in Beijing, clocked in at 57.46.
In the women's 400m free, half of the heat was composed of Olympians. Open water Olympian Chloe Sutton (Mission Viejo, Calif.), whose specializes in races that are more than six miles long, sprinted to the front of the pack for the first 300 meters.
On the final 100 meters, fellow Olympian Alison Schmitt (Canton, Mich.) dug deep overtake the lead and cement her trip to World Championships in a time of 4:06.77. Sutton joined Schmitt on the podium as the silver medalist with a time of 4:07.20, while Olympian Caroline Burckle (Louisville, Ky.) was third in 4:09.61.
Two-time Olympian Peter Vanderkaay (Rochester, Mich.) cruised to the win in the men's 400m free in a time of 3:45.17. Daniel Madwed (Stamford, Conn.), who traditionally swims butterfly, posted the silver-medal time of 3:47.24. Michael Klueh (Evansville, Ind.) rounded out the top three in 3:50.98.
Six swimmers were named to the 2009 World Championship Team at the conclusion of the session, including Magnuson, Smit, Schmitt, Vanderkaay, Gangloff and Lochte. If space allows on the team, the second-place finishers will also be named to the team. For complete qualifying procedures, click here . Competition continues Wednesday with the men's and women's 100m back and 200m free, as well as the men's 200m fly. Prelims will begin at 9 a.m. ET, and finals will begin at 6 p.m. ET.
The USA Swimming 2009 ConocoPhillips National Championships and World Championship Trials are being held at Indianapolis' IUPUI Natatorium from 7 July through 11 July. The 2009 World Champs are in Rome 17 July through 2 August.