STEVENS POINT, Wis. (AP) -- The death of a senior who collapsed during track practice at Stevens Point Area High School in April was caused by heart problems.

The Portage County Coroner says Jason Schultz suffered an electrical disturbance in his heart that had been triggered by a diseased heart.

Coroner Scott Rifleman says today it's unknown how or when the 18-year-old's heart became affected by disease.

The teen collapsed at practice on April third and was rushed to a hospital but couldn't be revived.

His death was the first of three for Wisconsin teens at track practices this spring.

Adam Luing, a high school junior, died April 17th after collapsing during track practice at Brookwood High School in Ontario.

On May ninth, 13-year-old Alysa Sadowski died after saying she felt sick at track practice in Beaver Dam.

Autopsy results have not been released in either of those deaths.

(Copyright 2007 by The Associated Press. All Rights Reserved.)