Trainer John Charles Zimmerman died of a heart attack April 9 in his Aventura, Fla., home. He was 46. Zimmerman, a native of Palmyra, Pa., was enjoying a good meet at Gulfstream Park. He scored his 13th victory of the stand Friday when Letters took the sixth race of the day.Zimmerman went right from high school to the racetrack in 1977, honing his skills at his hometown racetrack, Penn National. Saddling Procreate to a world-record performance in last year's Yankee Affair Stakes was one of the highlights of his years at Gulfstream. He was readying that horse for a repeat in next Saturday's renewal of the race.Zimmerman is survived by his fiancee, Kim Markley, a daughter, Mallory, and sons Matt and Brett. A memorial service will be held April 20 from 2:30 to 6:00 at Trefz Bowser Funeral Home, 114 Main Street, Hummelstown, Pa.