Incidence of atrial fibrillation in patients with different mode of pacing. Long-term follow-up

We evaluated the incidence of atrial fibrillation in 189 patients (92 males, 97 females, mean age 75 +/- 12yrs, range 41-100yrs) with pacemaker, during a mean follow-up of 5.5yrs (range 1-24yrs). The indications for implant were: complete AV block (115pts), second degree Mobitz 2 AV block (51pts), bifascicular block (5pts), sick sinus syndrome (14pts), symptomatic bradycardia (4pts). The mode of stimulation considered were VVI (105pt), VVI rate responsive (21pts), single lead VDD (43pts), DDD (20pts). The occurrence of retrograde VA conduction in patients with VVI or VVI rate responsive pacing was also evaluated. Atrial fibrillation occurred in 40 pts (21%). The highest incidence was evidenced in patients with sick sinus syndrome (9pts, 64%), and in patients with VVI stimulation (28pts, 27%). On the contrary, the lowest incidence was found in single lead VDD stimulation (4pts, 9%). The patients with dual chamber pacing showed a relatively high incidence of the arrhythmia (5pts, 25%). Atrial fibrillation occurred in 9 out of 32 patients with retrograde VA conduction, and in 22 out of 94 patients without retrograde conduction (28% versus 23%, p= NS). In conclusion, if is confirmed that patients with sick sinus syndrome are at high risk for atrial fibrillation. Single lead VDD stimulation seems to be the better mode of pacing in preventing atrial fibrillation, while dual chamber pacing shaved minor efficacy. The presence of retrograde VA conduction could not predict the occurrence of the arrhythmia.