Verification of ability of frequency domain signals in predicting imminent ventricular tachyarrhythmia.

摘要

Introduction. Previous studies have shown an increase in heart rate variability (HRV) spectral power of the ECG just prior to Spontaneous ventricular arrhythmia (VA). The specificity of these HRV changes in predicting VA is unknown. The purpose of this study was to verify that an increase in spectral power similar to that recorded by the ICD for similar patients just prior to VA does not take place at other times.; Methods. 19 24-hour Holter recordings were obtained from 19 patients at risk of VA. Control recordings from 11 healthy volunteers were also available. Beat string data containing the RR intervals were extracted and the instantaneous heart rate (IHR) calculated was resampled at equal 0.5-second intervals using a cubic spline fit. Mean whole band power (MWBP, Ŵ) of the HRV signal in the 0–1HZ band was obtained using a periodogram approach for continuous non-overlapping 500-second windows. The changes in the MWBP (Ŵ) from one 500-second window to the next over the course of the Hotter recording period were calculated for both Hotter patients and Hotter controls. Differences in Ŵ from one 500 second window to the next (Difference in Ŵ between windows after which no VA followed, non event) were also calculated for all the Hotter controls (Ŵ_Controls ) and all the Holter patients (Ŵ_Patients ) and compared with Ŵ data obtained from ICD (Ŵ_ICD) (Difference in Ŵ between window after which VA followed (event) and window in which no VA followed, (non event)).; Results. The shortest recording available was for 17.63 hours and this length was used for all the analysis. Using General Linear Model (GLM) repeated measures analysis of variance (RM ANOVA), it was found that there was no significant difference in the MWBP (Ŵ) over the course of the Hotter recording period for Hotter patients (p = 0.1330). It was found that there were significant differences in the MWBP ( Ŵ) over the course of the Hotter recording period for Hotter controls (p 0.0001). There were no significant differences in the MWBP (Ŵ) from one window to the next for both control and patient recordings (minimum p = 0.074, patient data; minimum p = 0.063, control data).; Conclusion. Our results suggest that sudden increases in mean whole band spectral power (0–1Hz.) may be an indicator for imminent VA.