Heart disease killed a seemingly healthy college freshman who was stricken on a flight home to the Twin Cities for winter break, autopsy results released Thursday disclosed.

The Minnehaha County coroner's office in Sioux Falls, S.D., where the flight was diverted on Dec. 22, found that Griffin Gutwa, 18, of Burnsville, fell victim to hypertrophic cardiomyopathy, along with myocardial fibrosis.

The diseases thicken the heart muscle and valves. On Wednesday, Dr. Kenneth Snell, the coroner, said Gutwa had an enlarged heart.

Soon after the University of San Diego student collapsed, he was removed from the plane and hospitalized in Sioux Falls.

Services for the Burnsville High graduate are 3-6 p.m. Sunday at Southview Seventh-day Adventist Church, 5750 Wentworth Av. S., Minneapolis.