Figure 206-6

Induction of supraventricutartachycardia (SVT) in Wolff-Parkinson-White syndrome. The tracings are labeled. Atrial pacing from coronary sinus (CS) is done at a 700-ms basic cycle. During the basic drive pacing, left free wall accessory pathway conduction to the ventricle produces ventricular preexcitation. A single premature beat (Sr) blocks in the accessory pathway (AP) and conducts over the normal pathway with a left bundle branch block morphology, and the SVT is initiated. Note the intermittent normalization of the QRS complex during this SVT.

(From jazayeri et al. Reproduced with permission from the publisher and authors.)