Tachysystolic stage
Wiggers described the onset of ventricular fibrillation (VF) as initiated by a short run of premature contractions which he described as the tachysystolic stage (TCHS). In all CAD patients, there was a predominant morphology with right bundle branch and superior axis, which remind us of the morphology of VTs with origin in posterior papillary muscle. It is known that the papillary muscle plays a vital role in the generation and maintenance of reentry during VF13. It could be hypothesized that in patients with coronary arterial disease that Wiggers’ tachysystolic stage of VF is related to the activation of the posterior papillary muscle. It might also be considered that the activation proceeds from the scar in cases of inferior posterior infarction; in fact, the rotor has been located at the edges of the scar14. Favoring the hypothesis of the origin from the posterior papillary muscle, we have also seen this morphology in a case with anterior / lateral infarction , as well as in spontaneous cases of VF in ischemic patients regardless of the location of the scar location.
In VF cases in patients with Brugada, morphologies compatible with activation of RVOT predominate and less frequently in the moderating band. This RVOT morphology has been described previously15