Relationship Between Selected Overdrive Parameters and the Therapeutic Outcome and Tolerance of Atrial Overdrive Pacing

ATTUEL, P., et al. : Relationship Between Selected Overdrive Parameters and the Therapeutic Outcome and Tolerance of Atrial Overdrive Pacing. There is a paucity of information on the influence of selected overdrive parameters on the clinical efficacy and tolerance of atrial overdrive algorithms to suppress atrial tachyarrhythmias. Data from a completed clinical trial investigating a new DDD+ overdrive algorithm implemented in a permanent pacemaker were analyzed. One-hundred patients with standard pacing indications and atrial tachyarrhythmias were enrolled and followed for 6 months in DDD and 6 months in DDD+ mode in a randomized, crossover fashion. The overdrive step size was programmed at the discretion of the investigators between 4 and 12 beats/min, overdrive plateau length between 10 and 32 beats, and maximum overdrive rate between 100 and 160 beats/min. The effects of DDD+ versus DDD mode on burden and incidence of atrial tachyarrhythmias stored in the mode switch memory were examined as a function of the programmed overdrive parameters. An overdrive step size between 7 and 12 beats/min, and higher a maximum overdrive rate between 121 and 160 beats/min were slightly more effective than lower programmed values, though >500 randomized, crossover observations would have been necessary to verify statistical significance. Overdrive pacing related symptoms mandated early manual deactivation of overdrive pacing in 4.7% of 85 evaluated patients. Overdrive was disabled without testing tolerability of less aggressive overdrive values. There was no link between patient symptoms and programmed overdrive step size or overdrive plateau length values. (PACE 2003; 26[Pt. II]:257–263)