Time-frequency analysis of human polymorphic ventricular tachycardia

This study examined whether time-frequency analysis can reveal dynamic characteristics of human ventricular tachyarrhythmias. The authors investigated 11 episodes of self-terminating polymorphic ventricular tachycardia (PVT) recorded from 7 patients during routine electrophysiology studies. The mean duration was 7.3 s (range 3.7-15.6 s). Surface ECG leads I, aVF and VI were recorded, as well as a bipolar electrogram from the right ventricular apex (RVA). The time frequency distribution (TFD) was obtained using a smoothed Wigner distribution algorithm with a time resolution of 20 ms and a frequency resolution of 0.488 Hz. An identical dominant frequency was recorded on all 3 ECG leads 34.5% of the time. There was a significant correlation between the reciprocal of DomF obtained from the RVA signal, and the W interval (r=0.82, mean difference 0.2 ms SD 24.1 ms). In 8 of the 11 PVT recordings, DomF fell and W interval increased prior to termination. This study has shown that time frequency analysis is a valuable tool for investigating human tachyarrhythmias.