LARAMIE, Wyo. (AP) — A 22-year-old Wyoming man has pleaded not guilty to attempted second-degree murder in a June 22 stabbing in Laramie that damaged the victim's heart.

Jake Gillen of Laramie is charged in the stabbing that caused 30-year-old Terrence Gadlin to undergo open-heart surgery at a Colorado hospital to repair damage to his left ventricle.

Gillen entered his plea on Sept. 4.

Prosecutors say a source reported that the victim had attacked Gillen's girlfriend, leading to a fight between the two men. Gadlin also suffered other cuts and puncture wounds.

Gillen's girlfriend, who is charged with accessory after the fact, did not appear for her scheduled arraignment. Her attorney said she did not receive notice to appear due to a mailing error.