The Hilbert Marginal Spectrum Analysis and Feature Extraction of Short-Term Heart Rate Signal of Spontaneous Ventricular Tachyarrhythmia

The malignant ventricular tachyarrhythmia including ventricular tachycardia (VT) and ventricular fibrillation (VF) is the major cause of triggering sudden cardiac death (SCD) and it is seriously harmful to human. There is a great significance to predict the VT/VF. In this study, the RR interval series preceding the onset of VT/VF events are used as the study objects, and the 135 RR interval series are recorded by implantable cardioverter defibrillators (ICD) from 78 patients. Instantaneous heart rate (IHR) series are obtained after preprocessing the RR interval series. The Hilbert spectrum and the frequency marginal spectrum of IHR series are analyzed based on the traditional Hilbert-Huang transform (HHT) and the improved HHT. Some signal spectrum features are extracted from the marginal spectrum of IHR series: low frequency amplitude, high frequency amplitude, very high frequency amplitude, total amplitude and the low-to-high frequency amplitude ratio. The statistical analysis shows that the performance of improved HHT is better than that of traditional HHT. High frequency amplitude, very high frequency amplitude and total amplitude of IHR series preceding the onset of VT/VF are significantly higher than that of normal sinus rhythm (p < 0.003), and low-to-high frequency amplitude ratio is significantly lower than that of normal sinus rhythm (p < 0.0002).