Diastolic heart activity inspection from intracardiac electrogram analysis

Aim of this paper is to study unexpected electrical activities seldom observed during the diastolic interval of intracardiac electrograms (EGM) retrieved from patients with implantable cardioverter defibrillators (ICD). Five patients are considered. From them 29 EGM are retrieved in different cardiac conditions: 18 immediately before ventricular tachyarrhythmia (VT-EGM) initiation, and 11 in basal heart condition (BAS-EGM). Single interbeat intervals of each EGMs are selected, QRS-waves are blanked, and diastolic intervals are filtered in the 20-100 Hz bandwidth for each interbeat interval, then the frequency corresponding to the maximum power spectral density over all the diastolic traces is computed and considered as the characteristic parameter for that file. At least 20 beats for each EGM are investigated. Results show that unexpected electrical activities have overall median value of 36 Hz (Bas_EGM is 41 Hz, and VT-EGM is 35 Hz). At this stage of the study median values of Bas-EGM and VT-EGM are not significantly different at 5% level (p<;0.16 using Mann Whytney U-test for significance of medians).