Is there a role for pacing in the prevention of atrial tachyarrhythmias?

In this issue of EUROPACE, Blanc et al. [1] present data from one of the five PIPAF (Pacing in Prevention of Atrial Fibrillation) studies which assess the effects of pacing on prevention of atrial tachyarrhythmias (ATs) using different atrial pacing sites (conventional sites, septal, dual site right atrial and biatrial) alone or in combination with one or more dedicated pacing algorithms [2]. The present study evaluated the effect of pacing from the right atrial appendage or lateral free wall using conventional DDD pacing (lower rate limit set to 70 bpm, rate response activated if chronotropic incompetence present) with or without the addition of three simultaneously activated pacing algorithms. These algorithms are dedicated to achieve atrial pacing during sinus rhythm for almost 100% of the time, prevent post-extrasystolic pauses after premature atrial complexes (PACs), and apply more aggressive overdrive if an increase in PAC density is detected. The present study disappointingly suggests that the use of sophisticated pacing algorithms does not improve the ability of pacing to prevent ATs. Whenever there is disappointment with a treatment that has met considerable expectations, there is also a strong desire to explain why the study has failed. Expectations were based on the observations that atrial pacing for more than 80% [3] or 90% [4] of the time prolonged the time to AT recurrence from 9 to 143 days [3] and reduced the cumulative time in AT by almost 75% if DDDR mode alone achieved !50% of atrial pacing [4]. Similarly, prevention of post-extrasystolic pauses and a higher overdrive pacing rate in reaction to increasing PAC density reduced the number of PACs, the most potent AT trigger [5]. A combination of three preventive pacing algorithms, therefore, looked like a powerful tool against the recurrence of paroxysmal ATs. In light of this