Clinical trials of pacing for maintenance of sinus rhythm.

Several prospective randomized clinical trials have demonstrated that atrial-based pacing prevents the development of paroxysmal and persistent atrial fibrillation (AF) in patients with symptomatic bradycardia as the indication for a pacemaker. The greatest benefit appears to be in patients with sinus node dysfunction as the primary indication for pacing. Studies of site specific atrial pacing have not shown a consistent benefit for prevention of AF. A number of prospective studies have been undertaken to assess the role of selective atrial pacing algorithms designed for prevention of AF. These studies suggest that these AF pace prevention algorithms have modest to minimal incremental benefit compared to atrial based pacing alone for the prevention of AF. Atrial antitachycardia pacing (ATP) algorithms have been incorporated into some pacemakers and defibrillators. Overall, atrial ATP therapy has not been shown to substantially reduce the burden of AF in one randomized trial. However, there are subsets of patients e.g. those with atrial flutter as well as AF who are likely to benefit from this therapy.