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Figure 3 Atypical Activation Pattern in Left Atrium During Sinus Rhythm in Anteroposterior and Left Posteromedial Views, Respectively

(A) Anteroposterior view; (B) left posteromedial view. The earliest activation site occurred at the high posteroseptum with the wavefront extending to the roof, descending to the posterior wall near the left pulmonary vein, crossing over the lateral mitral isthmus, and ending at the left atrial appendage. Arrows indicate the activation wavefront.