Spacelabs Healthcare 98000, Operation Manual

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070-2567-03 Rev. A
15-7
3. To scroll up / down or left / right on the scale, click the Arrow buttons. To magnify areas
of interest, click the Zoom In / Out buttons. (Continue clicking the Zoom buttons to zoom
further in / out. To reset the chart to its original state, click the Reset button.
15.10 NN Interval Histogram Screen
The NN Interval Histogram screen shows the number of R-R intervals that occurred at each
discrete interval value over the analyzed period.
The HRV Triangular Index (HRV Index) represents the total number of Normal-to-Normal R-R
intervals divided by the largest number of equally long normal-to normal intervals (i.e., the
number of Normal-to-Normal intervals with modal duration).
The Triangular Interpolation of Normal-to-Normal (TINN) represents the minimum square
difference interpolation of the frequency distribution histogram of the Normal-to-Normal R-R
histogram. The TINN value (shown in the upper-right corner of the screen) indicates the length of
the triangle’s base in milliseconds.
TV: Total Variability. This is the variability from the largest valid NN to the smallest valid NN.
10%WP: Width at Percentage 10; this is the width from first to last crossing of a threshold set at
10% of the peak height value. This is often used to as a noise filter.
50%WP: Width at percentage 50; the equivalent to Full Width Half Max.
15.10.1 To use the NN Interval Histogram screen:
1. In the pane view on the left, click NN Interval Histogram.
2. To scroll up / down or left / right on the scale, click the Arrow buttons.
3. To magnify areas of interest, click the Zoom In / Out buttons. (Continue clicking the Zoom
buttons to zoom further in / out).