Ablation should be reserved for patients who are either very symptomatic with their atrial fibillation or for whom medication control has proven difficult or impossible. There are a couple of different types of ablation possible. If the specific areas of the heart that are causing the afib can be located, those areas can be directly ablated. This is frequently challenging, and a maze procedure is more commonly done. This involves isolating the electrical signal from the pulmonary veins (the most common source of afib) from the rest of the heart. This allows the normal parts of the atrium to function as normal. For patients in whom medication control and ablations such as a maze procedure do not work, it is possible to ablate the AV node itself, thereby preventing the signal from the rapidly beating atrium from reaching the ventricle. These patients simultaneously have a pacemaker inserted, and for the rest of their life will be dependent on the pacemaker.