A method of ablating tissue, comprises anchoring a first electrode at a first location in a target portion of tissue, deploying a second electrode at a second location in the target portion of tissue and applying current between the first and second electrodes to ablate a first ablation portion of tissue in combination with moving an insulative cover relative to the first electrode to move a conductive portion of the first electrode to a third location within the target tissue, the third location being further from the second location than the first location, moving the second electrode to a fourth location within the target tissue, the fourth location being further from the first location than the second location and applying current between the conductive portion of the first electrode and the second electrode to ablate a second ablation portion of tissue surrounding the first ablation portion of tissue.
