Methods and apparatus for treating a patient include an ablation device for treating atrial fibrillation. The device includes a housing having proximal and distal ends, and an energy source adjacent the distal end of the housing. The energy source has an active portion and an inactive portion. The active portion is adapted to deliver energy to tissue when the energy source is energized. This creates a partial or complete zone of ablation in the tissue that blocks abnormal electrical activity, thereby reducing or eliminating atrial fibrillation in the patient. The inactive portion does not emit energy or emits substantially no energy when the energy source is energized.