Mode of onset of spontaneous ventricular tachyarrhythmias from implantable cardioverter defibrillator electrograms

This work investigates the correlation between the cardiac electrical activity underlying spontaneous ventricular tachyarrhythmias and their modes of onset. We analyzed 81 episodes of spontaneous ventricular tachycardia (VT) and ventricular fibrillation (VF) lasting at least 5 seconds from 17 patients. The cardiologist classified VT/VF malignancy by considering fast VT as more malignant. We study 3 modes of onset: (i) premature ventricular contraction (PVC group); (ii) PVC preceded by a short-long-short cycle (SLS group); (iii) PVC preceded by a paced beat after a previous PVC compensatory pause (PM group). In 4 patients more than one mode of VT/VF onset is present, in the other 13 patients VT/VF always started with the same mode. Cardiac electrical activity is characterized by power spectral density and correlation dimension analyses; statistical analysis is carried on using one way ANOVA in order to test significant differences among the mean values of PVC, SLS and PM populations. Preliminary results shows significant differences at 5% level in two of the considered quantitative parameters. Although initial significant differences have been obtained, the limited number of ICDs and the small variability of the intra-subject characterization suggest that further research is needed to conclude that dynamics underlying VT/VF and the VT/VF mode of onset are strictly related.