Table 3.
| APG Features | Description |
|---|---|
| Ratio c/a, e/a | Indicates arterial stiffness. |
| Ratio b/a | Reflects increased arterial stiffness, consequently increases with age. |
| Ratio d/a | Indicates decreased arterial stiffness. Useful parameter for the evaluation of left ventricular afterload. |
| Ratio (b-c-d-e)/a | Valuable as a vascular aging and arteriosclerotic disease indicator. |
| Ratio (b-e)/a | APG aging index. |
| Ratio (c+d-b)/a | A more comprehensive aging index. |
| a-a Interval | Represents a completed cardiac cycle. HRV can be calculated using the a-a interval. |