Electrophysiologic assessment in selecting patients for multisite atrial pacing

Electrophysiologic mechanisms of atrial fibrillation (AF) initiation are be ing actively studied. Multisite atrial pacing has shown, in acute studies, significant potential for prevention of AF. Dual site pacing reduces of int ra and inter-atrial conduction time, atrial refractoriness dispersion, and to a limited extent atrial premature beats which modify the atrial remodell ing induced by AF. Recently, two clinical trials have shown long term effic acy of multisite atrial pacing. At 3 years of follow-up, 56% of patients ar e free of AF recurrence with dual site right atrial pacing. Rhythm control was achieved in 86 of patients. Similar results are observed with biatrial resynchronization. In both studies, primary indication for multisite atrial pacing was AF prevention in more than 50% of patients. Selection of patien ts based solely on long P wave duration and prolonged interatrial conductio n is not necessary as clinical outcome and comparable. These patients are c omparable to patients who did not have these characteristics. Ongoing multi center trials will likely definitively answer this question. However, preex citation of diseased atrial regions or site of ectopic activity previously selected by high density atrial mapping or suppression of inducible AF may offer an interesting future development of multisite atrial pacing.