Quantification of activation patterns during ventricular fibrillation in open-chest porcine left ventricle and septum

The lower incidence of reentry and lower peak frequency in the mapped region of the septum than in the LV indicate that a mother rotor is not present in swine on the RV side of the septum. The mean directions of the VF activation sequences in the LV and septum suggest that if a mother rotor is present during the first 20 seconds of VF, it exists where the posterior LV free wall joins the septum, the region where the posterior papillary muscle inserts.