PORTLAND – A motorist who was killed when he drove his car into oncoming traffic on the Maine Turnpike suffered from heart disease that contributed to the accident, according to the state medical examiner.

James W. Guillory, 50, of Biddeford was heading south on the turnpike at around 10 a.m. Monday when his car began swerving from one side of the road to the other, then shot across the paved median into the northbound lane.

Guillory drove about 700 feet straight into oncoming traffic before colliding with a minivan, witnesses said.

An autopsy by the State Medical Examiner’s Office on Wednesday determined that Guillory died from injuries but that his advanced heart disease was a “significant condition contributing to death.”