http://www.medscape.com/viewarticle/712199_4
Atrial Fibrillation Termination Algorithms
Antitachycardia pacing algorithms have proven to be quite effective for the termination of atrial flutter and slower organized AT. The fact, however, that both atrial flutter and tachycardia usually coexist in patients with AF has led to the incorporation of these algorithms in devices implanted in patients suffering from AF. These algorithms include 50 Hz pacing sequences, as well as burst and ramp pacing.

patients who received pacemakers (AT500, Medtronic Inc.) that incorporated three PPA (atrial pacing preference, atrial rate stabilization, and post-mode switch overdrive pacing)

https://www.researchgate.net/publication/31130777_Antitachyc...

Antitachycardia pacing therapies to terminate atrial tachyarrhythmias: The AT500 Italian Registry

Prevention algorithms
The device also has three prevention algorithms, which attempt to interact with atrial arrhythmia onset mechanisms. These algorithms consist of the following: an overdrive algorithm to achieve high atrial pacing percentages without increasing the patient’s programmed pacing rate (atrial preference pacing; APP); an algorithm to suppress the compensatory pause that usually follows a premature atrial contraction (atrial rate stabilization; ARS); and an algorithm that attempts to prevent early recurrences, increasing the lower rate up to a programmable value and for a programmable period after the end of an episode (postmode-switch overdrive period; PMOP)

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Note added at 51 mins (2016-08-31 21:02:34 GMT)
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http://circ.ahajournals.org/content/104/9/1023