562015-03-24 , 法政大学大学院理工学・工学研究科
This paper examines if the trend co-variability between QT and RR Intervals could be an index of the sudden cardiac death (SCD) risk assessment. Twenty four hour beat to beat QTIs and RRIs are measured from 25 normal control subjects (SCD-C), 14 low SCD risk patients (SCD-L) with high blood pressure or light cardiac arrhythmia and 11 SCD high risk patients (SCD-H) with heart attack history. The Kalman filtering technique has been applied to decompose 24 hour short term mean QTIs and RRIs sequences into trend components and additive random variations. The correlation coefficients (TC-QT/RR) and mutual entropies (TE-QT/RR) between the QT and RR trend signals are estimated. Optimal meta-parameters of state noise variances and observed noise variances are determined. With these optimization, cross entropy TE-QT/RR achieved the best stratification of subject groups.