Figure 1A narrow QRS tachycardia dependent on a jump-up in the AH interval was
induced by atrial extra stimulation.
The numbers indicate the cycle lengths in ms. II, V2, V5 = surface
electrogram; His d and His p = distal and proximal His bundle region; CS
d to CSOS = distal to proximal coronary sinus ostium; HRA = high right
atrium; RV = right ventricle; A and H = atrial and His bundle
electrogram.Figure 2During the tachycardia, intermittent AV dissociation was observed, and
the H-H intervals fluctuated.
(A) late coupled sinus complex
(B) early coupled sinus complex
asterisk = atrial contraction from the sinus node. The other
abbreviations are as in Figure 1.Figure 3The response to the ventricular overdrive pacing during the tachycardia.
arrow = The pacing stimulus at CSOS did not capture the atrium. rH =
retrograde His bundle potential. The other abbreviations are as in
Figure 1.