Two heart-rate delay groups, one poll apart¶
Solar8000 heart rate reaches the recorder either about 1.9 s or about 4.2 s after its window ends: one 2 s poll apart. The group belongs to the recording PC, stays fixed through a case, and on some PCs varies from case to case.
| Date | 2026-10-13 |
| Status | current |
| Methods | Delays and averaging windows |
| Devices | Solar8000 monitor, Vital Recorder |
| Variables | Solar8000 heart rate |
Data¶
6,222 cases with heart rate; window fits on 240 cases; a file scan of 657 cases on five ports.
Method¶
A two-component Gaussian mixture on the per-case HR delays, each case's standard error added to the component variance; a posterior of 0.9 assigns a group. Groups compared with the Solar8000 port, then with the full PC key (the ports of the four core devices), department, surgery, rhythm, case order and the HR records themselves.
Results¶
- Groups at 1.92 s (SD 0.51, 36%) and 4.20 s (SD 0.65, 64%): 1,775 cases early, 3,652 late, 795 uncertain.
- Not a different window: both groups fit 6–8 s best; the 2.1 s gap matches one Solar8000 record period. The arterial pressure numerics show no such split, so it is specific to HR.
- The PC decides, not the port: ports shared by several PCs separate almost completely by the full device signature (purity 0.90–0.97). On 44 PCs the majority group is right for 94% of cases.
- One-sided: late-majority PCs hold 0.7% early cases (about the misclassification rate); early-majority PCs hold 14% late cases (0–44% per PC).
- Stable within a case; nothing in the records (interval, stamp phase, first-record delay) tells the groups apart.
| Parameter | Value | Status | From |
|---|---|---|---|
| Solar8000 HR delay, early group | 1.92 s (± 0.51 SD; 36% of classified cases) | measured | Two heart-rate delay groups, one poll apart |
| Solar8000 HR delay, late group | 4.2 s (± 0.65 SD; 64% of classified cases) | measured | Two heart-rate delay groups, one poll apart |
Discussion¶
Late (one extra 2 s cycle) looks like the default path; some PCs have a faster path that on a given recording sometimes does not engage. What sets it is not in the release. The hr_delay_group label gives each case's group, and the PC gives a prior for uncertain cases.
Observations it supports¶
| Observation | Status | Summary |
|---|---|---|
| Solar8000 heart rate comes one poll early or late | established | Heart rate reaches the recorder about 1.9 s or about 4.2 s after its window ends, one 2 s poll apart. The group belongs to the recording PC and stays fixed through a case. |
Open questions¶
- The recording PC sets the fast path (weakly supported hypothesis). Some recordings get the Solar8000 heart rate one 2 s poll earlier, and on a given recording sometimes do not. The PC key predicts the group for 94% of cases, so the working explanation is the PC's polling path; what makes an early-majority PC deliver late in some recordings is not in the release.