A catheter for ablating target tissue from a location within a body vessel includes an ablation region that is configured to transition from a first substantially straight configuration to a second configuration having a two-dimensional or three-dimensional shape. The ablation region may include a plurality of ablation elements that may be distributed along a length of the ablation region such that when the ablation region is in the second configuration, the ablation elements may be placed in closer proximity to the target tissue. Additionally, when the ablation region is in the second configuration, the ablation elements may achieve circumferential coverage of the body lumen or blood vessel, and as such, may be capable of ablating the target tissue at multiple locations along the length and around a circumference of the body lumen or vessel in a single step.
