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Figure 7 Entrainment of Adenosine-Insensitive Focal Atrial Tachycardia From Patient #1

(A) Pacing from the early site at the ostium of the right superior pulmonary vein results in a post-pacing interval (PPI) equivalent to the tachycardia cycle length (TCL) of 510 ms. The morphology of electrograms in the coronary sinus (CS) and the P-wave are identical during entrainment pacing and tachycardia, consistent with a protected isthmus of a re-entrant circuit. (B) Electrogram at the earliest activation site is displayed at high gain, demonstrating marked fractionation with a duration of 111 ms and amplitude of 0.07 mV. ABL = ablation; d = distal; HIS = His bundle.