Actiheart User Manual 5.1.31 (Jun 2022)
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On each row of statistics, there will be a note if too few valid IBI points were
found to analyse, along with missing results. This indicates that whilst the
analysis can selectively use only valid IBI in the case of small amounts of missing
data, it will not do so where 50% or more of the time period is missing.
Note:
All time domain and frequency domain parameters are based on the
definitions contained in “Heart Rate Variability, Standards of Measurement,
Physiological I
nterpretation, and Clinical Use”. Task Force of the European
Society of Cardiology and the North American Society of Pacing and
Electrophysiology.
3.2.4 IBI Analysis
Settings
The IBI Analysis window menu provides settings options for Data-selective HRV
and HRV Bandwidth / Frequency.
Data-selective HRV: This option (selected by default) allows the calculations of
heart rate variability to attempt to use only those IBI which are considered likely
to be valid by the ECG processing. IBI marked invalid will be excluded from the
calculation.
It is ve
ry common in recorded ECG or IBI data to have sequences of “good” beat
sequence data interspersed with a smaller number of “bad” data periods where
reliable beat intervals could not be read. Most Heart Rate Variability (HRV)
measures are very sensitive to this, and can produce disproportionately high
output results from even small amounts of poor data. Note that this option must
be consistently applied
– results from “noisy” data processed with this option
should be compared to other data processed with this option, not without.
For the IBI sequence based calculations (max IBI, min IBI, ave IBI, SD, RMSSD)
the software will directly perform HRV calculations with invalid data points
excluded. Successive differences will only be calculated on adjacent valid IBI.
For FFT based HRV calculations (LF, HF, etc), the software will perform a
frequency analysis of the IBI signal with invalid data replaced with a straight-line
segment to minimize variability from that period. However, variability magnitude
is t
hen adjusted to “scale-up” the remaining variability measures to the full period
length. This will only be performed with over 50% of data valid, below which the
software will not produce HRV measures.
When the heart rate & movement graph is zoomed in far enough to show IBI, the
plot will also reflect the setting of this option:
No Data-selective HRV
Data-selective HRV
Invalid IBI
