Upper left panel: projection of the 192-unipolar electrode array on a schematic posterior view of the atria. Lower left panel: epicardial, unipolar potentials recorded during 5 s of SR containing atrial deflections (A) and far-field ventricular signals (V). Typical examples of nine unipolar potentials obtained from the RA are shown outside the mapping. Right panel: classification of potential type according to the number of deflections (f). Electrogram voltage is determined as the peak-to-peak amplitude of the steepest (primary) deflection. BB, Bachmann’s Bundle; FDT, fractionation delay time; ICV, inferior caval vein; LAA, left atrial appendage; LA, left atrium; PV, pulmonary veins; RAA, right atrial appendage; RA, right atrium; SCV, superior caval vein.