Incremental programming of atrial anti-tachycardia pacing therapies in bradycardia-indicated patients: effects on therapy efficacy and atrial tachyarrhythmia burden

AIMS: Efficacy of pace-termination of atrial arrhythmias (ATP) may depend on atrial cycle length and regularity. Whether device programming of ATP therapies can improve ATP efficacy and alter atrial tachyarrhythmia burden is unknown. METHODS AND RESULTS: ATP efficacy was evaluated in 61 patients (39 males; 66 +/- 10 years) with a standard indication for pacing, 95% with a history of AT/AF. Each patient was implanted with a novel DDDRP pacemaker capable of delivering ATP therapy. ATP efficacy and AT/AF frequency and burden were compared within each patient during a period of nominal ATP programming (NP) followed by a period of aggressive incremental programming (IP). Adjusted ATP-termination efficacy was higher during IP than during NP (54.8% vs 37.9%, P < 0.05). No differences in AT/AF frequency (3.3 +/- 5.9 vs 3.2 +/- 6.9 day(-1)) or burden (18 +/- 28% vs 18 +/- 29%) were observed comparing NP with IP. The majority of episodes during both the NP (81%) and IP (77%) periods terminated within 10 min. Episodes lasting 24 h or more accounted for only 0.4% of the episodes in both groups. but accounted for 38% of the average burden during NP and 51% during IP. CONCLUSIONS: Device programming of ATP therapies can influence the number of treated episodes and the efficacy of ATP therapies although arrhythmic frequency and burden may not change. Total atrial arrhythmia burden is disproportionately influenced by long (>24 h) episodes.