title: Reduction of atrial tachyarrhythmia episodes during the overdrive pacing period using the post-mode switch overdrive pacing (PMOP) algorithm.
abstract: BACKGROUND
  Early recurrences within 10 minutes after termination of an atrial tachyarrhythmia, such as atrial tachycardia (AT), atrial flutter, or atrial fibrillation (AF) episodes, account for a large part of paroxysmal AT/AF episodes. It is unclear whether these arrhythmias can be suppressed by overdrive pacing.
  
  
  OBJECTIVE
  We set out to prove that overdrive pacing is effective in preventing early recurrences of AT/AF.
  
  
  METHODS
  This AT500 (DDDRP device, Bakken Research Center Medtronic, Maastricht, The Netherlands) post-mode switch overdrive pacing (PMOP) study is a randomized controlled trial designed to test the efficacy of overdrive pacing on the suppression of early recurring AT/AF episodes. With the PMOP feature, overdrive pacing is activated 12 ventricular beats after device-confirmed termination of an AT/AF episode with a programmed duration and rate. If at least four episodes of 1 minute in duration occurred within the run-in period of 1 month, patients were randomized to one of the three settings (PMOP off and PMOP 10 minutes at 90 bpm or 120 bpm) for 2 months. At 2 and 4 months, patients were crossed over to another arm. At 6 months, all patients were programmed with PMOP on at 90 bpm for 30 minutes.
  
  
  RESULTS
  We enrolled 122 and randomized 50 patients. Sixty percent of all stored AT/AF episodes occurred within 10 minutes after a previous episode; 31% occurred after device-determined termination and before the device reached the overdrive rate (17-27 ventricular beats after termination), and 29% of the episodes occurred while the device was pacing at the programmed overdrive rate. Thirty-seven percent of the average percentage of episodes during the overdrive period was prevented by the randomized settings of PMOP 90 bpm/10 min (P = .01, paired t-test, n = 39) and 120 bpm/10 min (P = .03, n = 35). In addition, for the nonrandomized setting of PMOP 90 bpm/30 min, the average number of episodes during the overdrive period was significantly smaller than the percentage of episodes occurring during the corresponding off period of 30 minutes (P = .05, n = 33). No significant differences in burden and episodes were found between the PMOP settings and the corresponding off periods.
  
  
  CONCLUSIONS
  This is the first randomized controlled clinical trial to prove that overdrive pacing is effective in preventing early recurrences of AT/AF. However, shortcomings of the PMOP algorithm, such as late activation, need further improvement.
authors.affiliation: Public Hospital Elisabethinen Academic Teaching Hospital, Linz, Austria. helmut.puererfellner@elisabethinen.or.at
authors.forename: Helmut
authors.initials: H
authors.lastname: Pürerfellner
authors.forename: Jaap H
authors.initials: JH
authors.lastname: Ruiter
authors.forename: Joseph W M G
authors.initials: JW
authors.lastname: Widdershoven
authors.forename: Isabelle C
authors.initials: IC
authors.lastname: Van Gelder
authors.forename: Lubos
authors.initials: L
authors.lastname: Urban
authors.forename: Charles J H J
authors.initials: CJ
authors.lastname: Kirchhof
authors.forename: Ales
authors.initials: A
authors.lastname: Havlicek
authors.forename: Lilian
authors.initials: L
authors.lastname: Kornet
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D055502:Secondary Prevention; D016037:Single-Blind Method; D013612:Tachycardia, Ectopic Atrial / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D016896:Treatment Outcome