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Figure 2 Mechanical trauma in the retrograde direction to a left lateral accessory pathway during orthodromic tachycardia when manipulating the ablation catheter below the mitral annulus (Patient 16A). Note that the retrograde block in the accessory pathway occurs at a site where the ablation catheter shows early atrial activation (VA' = 70 ms). Also note the abolition of antegrade preexcitation on the second beat following tachycardia termination. Antegrade conduction over the accessory did not return during the following 30 s until an "immediate" pulse of radiofrequency energy was administered. The figure is arranged as in Figure 1.