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Solar8000 heart rate

Heart rate from the Solar8000, in one of two delay groups per case.
Name in the dataset Solar8000/HR
Type numeric
Device Solar8000 monitor
Stamped by Recorder PC clock
Unit /min

Description

The Solar8000 computes heart rate from its own ECG as 60 / median R–R over about 6 s, truncated, and the recorder polls it every 2 s. The value is stamped on arrival, one or two polls after its window ends depending on the recording PC (Solar8000 heart rate comes one poll early or late). Per-case delay labels fix the offset to a few hundred ms.

Measurement space

Time side (after the per-case delay label): the true time lies between -8.61 s and -0.12 s from the stamp: the delay range plus the interval one value describes.

Time

From UTC to the stored time stamp

The clock path first (UTC to the clock that stamps or spaces the samples), then the signal's own path to its stored time. Each bar: the time shift or error the step introduces (pale) and what is left after the atlas's correction (solid), on a log scale; dashed when estimated or assumed.
UTC
The reference every chain starts from.
Recorder PC clock
sync assumed 3 ms – 900 ms · clock link, parameter
Windows time synchronisation to the hospital's time server every 8–24 h (assumed), drifting a few ppm in between. Not observable in the release: dates are shifted to 2100. No step of 0.5 s or more was found.
Heart rate algorithm
window measured 6 s – 8 s
The Solar8000 averages heart rate over a window of about 6–8 s of ECG.
Polled by the recorder
transport measured 1.05 s – 5.25 s → 120 ms – 610 ms after correction
The value reaches the recorder 1.05–2.3 s after its window ends in the early group of cases, or 3.6–5.25 s in the late group (one extra 2 s poll cycle). A per-case delay label fixes the offset to 0.12–0.61 s (standard error, p10–p90).
Stored stamp
stamping estimated 1 ms – 20 ms
Stamped by the recorder on arrival, on a 1 ms grid; the receipt latency is not measured.

Timing

Against the working reference. Delay: from the end of the interval a value describes to its stamp. Interval: how wide that interval is.

Form Delay Interval Clock domain Status Evidence
after the per-case delay label (default) 120 ms – 610 ms 6 s – 8 s Solar8000 numerics measured numeric_delay label SE p10-p90 0.12-0.61 s (6,222 cases; 795 group-uncertain)
as stamped, early group 1.05 s – 2.3 s 6 s – 8 s Solar8000 numerics measured delay p10-p90 1.05-2.3 s, 1,775 cases; best window 6-8 s
as stamped, late group 3.6 s – 5.25 s 6 s – 8 s Solar8000 numerics measured delay p10-p90 3.6-5.25 s, 3,652 cases; one extra 2 s cycle; follows the PC

Combine it with other signals in the synchronisation planner.

Delays

Averaging window

Heart rate window (about 6 s (best 6–8 s in both delay groups)): 60 / median R–R over about 6 s, truncated to a whole beat per minute.

Value

Its value side is still to be described.

Parameters

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
Solar8000 HR window about 6 s (best 6–8 s in both delay groups) measured How the monitors compute their numbers

Observations

Observation Status Summary
Monitor numerics describe the past, never the future established Every monitor numeric describes a window of 3–30 s or more that ended 1–9 s before its stamp. None is stamped before its data exist, so the stamps already respect the availability rule.
Numeric delays are fixed within a case but differ between cases established A numeric's delay does not drift through a recording, but 40–70% of its variance lies between cases. One delay per case describes it; one delay for the whole dataset is wrong by up to about 2 s.
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.
Solar8000 heart rate is truncated, not rounded established The Solar8000 heart rate drops its fraction (floor), in 24 of 24 pilot cases; the respiratory rate rounds.

Studies

Study Date Status Summary
The SNUADC clock through the Solar8000 numerics, whole release 2026-10-19 current On the SNUADC's own sample count, the delay from the waveform to the PC-stamped Solar8000 heart rate and mean arterial pressure ramps at the SNUADC's drift against the PC, measured without its stamps or resets. In recordings with whole reset intervals it agrees with them (−63 ppm; median difference +1.5 ppm, 581 recordings). It is too noisy per recording, and in recordings under about 4 h its rate is biased toward zero, so it cannot yet speak for recordings without resets.
Value resolution of every signal 2026-10-19 draft How finely every waveform and numeric track in the release records its values. The SNUADC waveforms are 10-bit codes, though VitalRecorder's documentation describes the SNUADC as 12-bit; Primus waveforms use about 10 bits of 12; BIS EEG is a 16-bit grid of 0.05 µV. Numerics are 32-bit floats on decimal grids of 1, 0.1, 0.01 or 0.001, one per track; settings sit on coarser grids of 10 or 100.
SNUADC against the PC-stamped heart rate 2026-10-17 current The Solar8000 heart rate is stamped by the recorder on arrival, so the delay from the ECG to it, on the ECG's raw sample count, ramps at the SNUADC clock's rate: −65.3 ppm, against −66.7 ppm from the stamp model. Two independent routes agree.
Two heart-rate delay groups, one poll apart 2026-10-13 current 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.
Numeric delays are fixed within a case, different between cases 2026-10-12 current With each numeric's algorithm held fixed, delays were fitted for every case and every 30-minute block. They do not drift within a case, but 40–70% of their variance lies between cases, so a single population delay is wrong by up to 2 s for HR and 1 s for the others. Each case gets its own delay label.
How the monitors compute their numbers 2026-10-12 current Recomputing each monitor numeric from its own waveform finds a short, simple algorithm for every one (a median, an exponential average or a time mean over 3–30 s) and a delay of 2–9 s behind the newest data it uses. No value is stamped before its data exist.