Patients with permanent pacemakers have a high risk of atrial fibrillation (AF), particularly those with hypertension, sinus node dysfunction, and those with short episodes of atrial arrhythmias, known as atrial high-rate episodes (AHRE). AHRE are felt to be a precursor to AF, and may be both the result and a cause of changs in the atrial electrophysiology, and structure (known as cardiac remodeling)that are associated with the development of AF.