Table 1.
Summary of time-domain features.
| Feature index | Feature name | Physical meaning |
|---|---|---|
| 1 | m_RR | mean value of RR intervals |
| 2 | sd_RR | standard deviation (SD) of RR intervals |
| 3 | m_IntS1 | mean value of S1 intervals |
| 4 | sd_IntS1 | SD of S1 intervals |
| 5 | m_IntS2 | mean value of S2 intervals |
| 6 | sd_IntS2 | SD of S2 intervals |
| 7 | m_IntSys | mean value of systolic intervals |
| 8 | sd_IntSys | SD of systolic intervals |
| 9 | m_IntDia | mean value of diastolic intervals |
| 10 | sd_IntDia | SD of diastolic intervals |
| 11 | m_Ratio_SysRR | mean value of the ratio of systolic interval to RR interval of each heart beat |
| 12 | sd_Ratio_SysRR | SD of the ratio of systolic interval to RR interval of each heart beat |
| 13 | m_Ratio_DiaRR | mean value of the ratio of diastolic interval to RR interval of each heart beat |
| 14 | sd_Ratio_DiaRR | SD of the ratio of diastolic interval to RR interval of each heart beat |
| 15 | m_Ratio_SysDia | mean value of the ratio of systolic to diastolic interval of each heart beat |
| 16 | sd_Ratio_SysDia | SD of the ratio of systolic to diastolic interval of each heart beat |
| 17 | m_Ratio_S1RR∗ | mean value of the ratio of S1 interval to RR interval of each heart beat |
| 18 | sd_Ratio_S1RR∗ | SD of the ratio of S1 interval to RR interval of each heart beat |
| 19 | m_Ratio_S2RR∗ | mean value of the ratio of S2 interval to RR interval of each heart beat |
| 20 | sd_Ratio_S2RR∗ | SD of the ratio of S2 interval to RR interval of each heart beat |
Note: ∗ means the new added features in this study.