According to these guidelines, an episode of AF is defined as an event lasting greater than 30 seconds in duration. Paroxysmal AF refers to patients with spontaneous termination of the arrhythmia within 7 days of its onset. Most patients spontaneously going in and out of AF on their own fall into this category. Persistent AF refers to patients with sustained arrhythmia beyond 7 days. Most patients in this category require the use of a therapeutic intervention to restore normal sinus rhythm. Long-standing persistent AF refers to patients with uninterrupted AF for more than 1 year. Permanent AF refers to patients in which efforts to restore normal sinus rhythm have either failed or been forgone. These categories are not mutually exclusive and it is common for patients with one type of AF to exhibit overlapping features of another type. In particular, the distinction between 'long-standing persistent' and 'permanent' AF largely reflect a treatment intention to restore normal sinus rhythm, or accept AF respectively among patients who have been in AF for more than 1 year.