1. Patients undergoing planned, elective AF surgery, either as a stand-alone procedure or as a concomitant cardiac operation.

2. Patients will have either a Cox-Maze procedure (full-biatrial lesion set) or surgical pulmonary vein isolation (PVI).

3. Patients 18 years or older.

4. All eligible patients will be considered, regardless of gender or race.

5. Patients able and willing to provide informed consent and willing to comply with the required interval follow-up.

Medtronic Reveal XT Study