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Figure 5 LA APD Restitution Is Less Steep in Persistent AF

(A) This PAC is early (coupling interval 180 ms), yet significant activation time (AT) delay (93 ms) enables capture (see blocked stimulus artifact at ERP, 170 ms). This prolongs DI and flattens APD restitution. (B) This early PAC also encounters AT delay (106 ms). The APD restitution has a maximum slope 0.85 (i.e., also not steep; same patient as in Fig. 2B). In both patients, FRP (minimum interval from prior beat to PAC) is longer than ERP (minimum distance between stimuli). See Table 2. ERP = effective refractory period; FRP = functional refractory period; other abbreviations as in Figures 1 to 3.