Figure legends:
Figure 1 shows 12 lead ECG lined up with intracardiac His
electrogram (His-d represents the distal bipole and His-p represents the
proximal bipole) traces
Figure 2 Explanation for Figure 1
Upper panel corresponds to the 12 lead ECG and intracardiac EGMs
as in figure 1 (with annotated EGMs). It shows that the atrial and His
potentials are occurring near simultaneously and hence could be
isorhythmically dissociated or each His potential could be the result of
the previous atrial potential. There is progressive HV prolongation and
RR shortening followed by a block; Annotations H- His, A- atrium, V-
ventricle. The origin of atrial depolarisation is depicted by the dotted
lines
Lower panel shows ladder diagrams corresponding to the
intracardiac EGMs depicts 4:3 infra-Hisian Wenckebach sequence and
presumed isorhythmic dissociation of atrium and His signals.