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Figure 5 Activation Change in the PV With P

Panels A and B represent 1 PV in the presence and absence of P, during pacing at 400 ms. (A) At baseline, earliest activation (*) is noted at the lower right (distal PV), indicating breakout in the unmapped posterior one-third of the PV. (B) With P, earliest activation (*) shifts to the opposite end (left) of the distal PV, with a resulting change in the direction of activation. Each isochronal step represents 1 ms. Abbreviations as in Figure 1.