Template matching analysis of unipolar and bipolar electrograms in the differentiation of ventricular tachycardia and fibrillation from sinus rhythm

The failure of automated morphologic detection of ventricular tachycardia (VT) or fibrillation (VF) is a limitation of implantable cardioverter-defibrillators. As an adjunct to rate-based criteria, this study evaluated the use of waveform analysis of intracardiac electrograms with correlation waveform analysis (CWA). Using digital signal processing, unipolar and bipolar electrograms were evaluated in sinus rhythm (SR), VT, and VF at 1-500 Hz and 10-80 Hz in 15 patients. There was complete differentiation of SR from VF in 13/15 patients and VT in 14/15 with unipolar and 14/15 patients with bipolar electrograms at 1-500 Hz; at 10-80 Hz SR was differentiated from VF in 12/15 patients and VT in 13/15 with unipolar and from VF in 14/15 patients and VT in 13/15 with bipolar electrograms. It is concluded that differentiation of intracardiac waveforms by CWA is independent of electrode configuration and is not significantly altered by moderate signal filtering