The PIPAF trials are a set of randomized multicenter studies which seeks to evaluate the potential preventive effect of different modes of pacing in patients with drug refractory paroxysmal atrial fibrillation by means of a permanent pacemaker. The objective of the studies are (1) to significantly prolong the time to first recurrence of atrial arrhythmia and (2) to significantly reduce the cumulative arrhythmia duration. The role of the atrial pacing site (left or right), the overdriving of the sinus rate, and the suppression of the post extrasystolic compensatory pause are evaluated alone or in association, giving rise to four distinct pacing protocols. Over a period of 2 years, 220 patients will be included in 35 centers from 5 different countries.