FIGURE 11.

An A‐H‐H‐A response after overdrive pacing in AVNRT. During atrial pacing, the tachycardia (arrhythmia 1) is terminated and the last atrial paced beat results in two His signals as conduction proceeds anterograde down both the fast pathway and slow pathway and reinitiates the tachycardia (arrhythmia 2). (A, atrium; ACL₁, arrhythmia 1 cycle length; ACL₂, arrhythmia 2 cycle length; AVN, atrioventricular node; FP, fast pathway; H, His; PCL, pacing cycle length; SP, slow pathway; V, ventricle)