Objective To analyze the unipolar electrogram from successful and unsuccessful ablation sites of focal atrial tachycardia (AT), and to evaluate its value in the identification of successful targets.Methods Fifteen consecutive patients with focal AT were referred for radiofrequency catheter ablation (RFCA). Both unipolar (from the tip electrode of ablating catheter) and bipolar (from the distal pair of electrode of ablating catheter) electrograms were used to identify the ablation targets of focal AT.Results Successful ablation was echieved in 14 patients. Radiofrequency energy was delivered at a total of 27 sites. The bipolar electrograms associated with successful ablation sites showed earlier atrial deflection relative to P wave onset (36 ms±15 ms vs 30 ms±11 ms, P