The present disclosure provides ablation catheters that are constructed such that they may be inserted into the body and into a target blood vessel in a linear conformation and subsequently changed into a helical conformation using a pull wire secured to the ablation catheter prior to an ablation procedure to allow electrodes present on the ablation catheter to contact the wall of the blood vessel. After the ablation is complete, the helical-shaped ablation catheter may be returned to its linear conformation by reversing the tensioned pull wire for extraction from the body.