Transitions
The transitions would correspond to the complexes that separate the
programmed stimulation from the above mentioned triggers and between
defined phases in established VF (tachysistolic, sinusoidal). Two
morphologies of QRS complexes appear at the beginning of VF induction
and in the transitions between stages, mainly between the tachysistolic
and sinusoidal phases.
1.Narrow complexes: These morphologies may suggest the participation of
Purkinje fibers as principal nexus between different activation zones in
VF (Fig 6).
2. Complexes QRS characterized by a very high J point. The J point of
extrastimulus which trigger VF has greater amplitude than those with
longer coupled interval which do not triggering VF. There is actually a
progressive increase in the amplitude of J point (Fig 7.1,7.2, 8). This
phenomenon (elevated J point) can also be observed in the transition
between the VF stage with differentiated QRS (tachysystolic) to the
sinusoidal stage (when there is no clear QRS complex, only sinusoidal
waves).