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).