A NEW PACEMAKER FOR PAROXYSMAL ATRIAL-FIBRILLATION TREATED WITH RADIOFREQUENCY ABLATION OF THE AV JUNCTION

Atrial fibrillation is a relative contraindication to atrial synchrono us pacing because of the risk of the tracking of rapid atrial rhythms by the pacemaker. In this study, we describe the clinical results of a n AV synchronous rate responsive pacemaker with an original algorithm, which is able to sense pathological increments in atrial rate and aut omatically to switch into a non-AV synchronous mode of pacing. This pa cemaker was implanted in 12 patients who had undergone radiofrequency ablation of the Ab junction in order to cure severely symptom atic, dr ug refractory, paroxysmal atrial fibrillation. in an acute, intrapatie nt comparison between the standard AV synchronous mode and the automat ic switching mode, ventricular tracking of atrial fibrillation occurre d in 35% and 4% of total beats at rest and in 24% and 2% of total beat s during exercise, respectively (P < 0.001). During 5 +/- 4 months of follow-up, no further tachyarrhythmia related symptoms occurred. in co nclusion, the standard DDDR mode is unable to eliminate ventricular tr acking of atrial fibrillation, thus undermining the efficacy of AV jun ction ablation therapy. The automatic switching mode eliminates this a dverse effect of dual chamber pacing.