Effect of filtering upon morphological methods for arrhythmia detection in implantable devices

Morphological analysis of intracardiac electrograms (ICEs) has been proposed as a complementary method for discrimination of monomorphic ventricular tachycardia from sinus rhythm by implantable pacemaker-cardioverter-defibrillators. This study compared the impact of filtering on two previously proposed time-domain methods: (1) correlation waveform analysis (CWA-independent of both amplitude fluctuation and ICE baseline) and (2) difference of area (DOA-dependent on amplitude fluctuation and ICE baseline). Using a statistical validation method for nonparametric distributions requiring 75% separation with 95% confidence interval, it was found that with CWA a bandwidth of 10-80 Hz gave results equivalent to that in wideband recordings, and in DOA a bandwidth of 20-80 Hz retained equivalent discriminatory power. A further increase in the lower passband limit (20-80 Hz for CWA and 30-80 Hz for DOA) reduced effectiveness of the methods