Sudden cardiac death risk assessment based on heart rate diurnal variation and alternans ratio

Abstract

This study proposes to utilize diurnal change in beat to beat heart rate series and alternans ratio percentile (ARP) for the risk assessment of sudden cardiac death (SCD). These two parameters are obtained by Holter cardiogram. The advantages to utilize risk indices from Holter recordings are twofold: firstly, the data are recorded in natural daily activity, i.e. not stressful compared to lab examination, long term recordings may have more chances to detect abnormality compared to conventional short term ECG recordings. Subjects are divided into three groups, i.e. SCD high risk (SCD-H), low-risk (SCD-L) and control (CTL). The number of cases are 11, 14 and 25 respectively. Combining two indices, serial correlation coefficient between RR and QT intervals and APR, resulted in sensitivity and specificity both above 0.8 except for sensitivity of SCD-H group. Classification accuracy is promising if the SCD-H detection sensitivity will be improved by introducing additional indices.