In one embodiment, the present invention provides a bipolar ablation device with multiple needle electrodes that penetrate a desired target tissue. These electrodes may be arranged in a variety of therapeutically effective arrangements, such as a comb-like shape, a multi-needle wheel, or an expanding bow design. By contacting and preferably penetrating the cardiac tissue with bipolar electrodes, a user can more precisely create ablation-induced scarring and thus electrical block at desired target locations without causing unwanted damage and related complications.