The aim of this prospective multicenter study was to assess the clinical benefits of the Selection (Vitatron) pacemaker diagnostic functions (AF 1.0) in the management of AF. Forty patients (71 +/- 9 years of age), with documented AF and conventional pacing indications, received a Selection. The AF 1.0 function of the pacemaker was programmed to document the AF burden, onset, daily distribution, duration, premature atrial beats before onset, and mode of onset of the last 12 episodes for AF episodes exceeding 180 beats/min. By comparing patients' symptoms records, patient conventional assessment at follow-up and AF 1.0 data, the investigators evaluated the usefulness of AF 1.0 in AF management at 3- and 6-month follow-ups. Usefulness was defined as a change in arrhythmia management prompted by the disclosure of AF 1.0 data. AF recurrences were recorded in 71% of the follow-ups with symptoms reported by patients in only 16%. Thirty-nine percent of therapeutic changes based on conventional assessment were confirmed by AF 1.0 data, and in 61% of instances, the initial changes were modified by AF 1.0 data. Changes included pacing parameters in 56% of cases, AF prevention with pacing algorithms in 37%, and medical treatment in 7%. All investigators indicated that AF 1.0 was useful in all patients. The AF 1.0 diagnostic functions offered a unique documentation of AF in asymptomatic patients, and allowed therapeutic adjustments impossible otherwise.