Research Article
The Prediction of Atherosclerosis Index Based on Photoplethysmograph
Table 1
PPG signal extraction features and formulas.
| Number | Feature | Define | Formula |
| 1 | CT | Crest time | CT = t2 | 2 | CTR | Crest time ratio | CTR = t2/T | 3 | K | Slope | Kslope = t1 | 4 | PPT | Pulse wave transit time | PPT = t5 | 5 | SI | Stiffness index | | 6 | RI | Reflection index | | 7 | EF | Ejection fraction | | 8 | T | T is the pulsation period | See T in Figure 3 | 9 | HR | Heart rate | | 10 | K value | A PPG feature value | Shown (1) |
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