Rhythm classification by correlation-waveform morphology analysis of atrial and ventricular electrogram signals

We tested the use of correlation-waveform analysis (CWA) of atrial and ventricular electrograms (EGMs) to distinguish ventricular tachycardia (VT) from supraventricular tachycardia (SVT). Patients undergoing electrophysiologic testing were enrolled. EGMs recorded during induced tachycardias were compared with EGMs recorded during sinus and paced rhythms, taken as templates, by assigning a CWA percent-match (CPM) score. Twenty-two patients were studied: 15 men and 7 women (mean age 48 years); 16 with SVT and 6 with VT. Using a sinus-rhythm template, the atrial CPM scores for SVT and VT were 66%+/- 20% and 93%+/- 5%, respectively (P = 0.0034). With a CPM-score cutoff of 85%, the sensitivity for correctly identifying VT was 100% and the specificity for rejection of SVT was 80%. The corresponding ventricular-CPM scores for SVT and VT were 81%+/- 12% and 72%+/- 24%, respectively (P = 0.13, cutoff = 65%, sensitivity = 50%, and specificity = 90%). Using a ventricular template with atrial pacing, the ventricular-CPM scores for SVT and VT were 87%+/- 9% and 76%+/- 14%, respectively (P = 0.028, cutoff = 70%, sensitivity = 50%, and specificity = 93%). Atrial CWA matching is superior to ventricular CWA matching in discriminating between SVT and VT. CWA matching in both chambers could potentially achieve better discrimination.