Figure 2
Intracardiac electrograms during RV extrastimulation. (A) The earliest
atrial activation is seen in the distal CS with ventricular
extrastimulus coupling intervals from 400 to 290 ms at a basic pacing CL
of 600 ms, suggesting the presence of a left lateral accessory pathway.
(B) The earliest activation shifts to the HB region with a ventricular
extrastimulus coupling interval of 280 ms, suggesting the presence of
retrograde fast pathway conduction.
Abbreviations are as in Figure 1.