A pacemaker is a small electrical device implanted in the body, with wires going to the heart to regulate the heartbeat. It is implanted under the skin near the collarbone and sends out an electrical signal to keep a steady contracting rhythm in the heart. Some pacemakers sense when the heartbeat is too fast or too slow and then fire impulses that help the heart return to the proper rhythm and speed.
Downloadable patient information sheet: What is a pacemaker? (PDF)
Open-heart maze procedure
Maze heart surgery is a complex procedure in which a surgeon creates small cuts in the upper part of the heart. Stitching the cuts together forms scar tissue. The scar tissue interferes with the transmission of the electrical impulses that can cause atrial fibrillation, which restores a normal heartbeat.