Remarks on non-conventional cardiac electrical activity characterization from implantable cardioverter defibrillator signals

Implantable Cardioverter Defibrillators (ICDs) can store intracardiac electrograms (EGMs) with 2 modes of recording: bipolar (BIP) or far-field (FF). Aims of this study are: (i) to propose a non conventional Cardiac Electrical Activity Characterization (CEAC); (ii) to investigate the mode of recording that better allows retrieving information from measured EGMs with CEAC. We consider 293 EGMs during sinus rhythm (SR) or ventricular tachyarrhythmia (VT) from 40 patients implanted with ICDs. 196 were FF EGMs and 97 BIP EGMs. CEAC analysis of SR rhythms (FF vs. BIP) shows sensitivity 81.5% and specificity 93.6%; with VT rhythms both were 100 %. CEAC analysis of FF signals (SR vs. VT rhythms) give sensitivity 92.7 and specificity 79.7; with BIP EGMs they are 60% and 73.3%, respectively. We conclude that: (i) CEAC analysis requires to analyze FF or BIP signals separately; (ii) CEAC better discriminates SR from VT when far-field EGMs are used.