Alberta MP Jim Hillyer, who was found dead in his Ottawa office last week, died from a heart attack, an autopsy confirms. (Parliament of Canada)

An autopsy confirms that a 41-year-old Alberta M-P died of a heart attack last week in his Parliament Hill office.

Conservative Jim Hillyer had just returned to the capital following surgery to treat an infection in his leg.

He died of cardiomyopathy which may have been related to an undiagnosed pre-existing heart condition.

It might have also been caused by chemotherapy he underwent in 2003 while battling leukemia.

Hillyer broke a leg in a skiing accident in 2013 and took three weeks off for surgery and rehabilitation.

But he was plagued with infections that required subsequent surgeries.