The Evening News revealed last month that the League One club were interested in Petkov and the temporary move has now gone through.
He will move to Cumbernauld until January 20 to gain more first-team experience. "We are delighted to have finalised the loan deal for Alex," said the Clyde manager Danny Lennon. "He has great technical ability in all areas of the game - required of a modern centre-half - as well as composure, the ability to read the game intelligently and a strong physical presence.
"He will bring competition in both the centre-half and defensive midfield areas. We are grateful to Hearts for their trust. We believe that we can help the player in his development and journey, whilst at the same time adding to the quality we have in our squad."