.
45
points forms a sub-wave. Determine whether each sub-wave is a recognizable minimum wave
(see the definition below). If it is a recognizable minimum wave, first identify its direction. If it
is above the QRS baseline, it is R wave, if it is below the baseline, it is Q wave or S wave. Find
the extreme value of this wave, and the difference between the extreme value and the baseline is
the amplitude of Q/R/S wave.
Note: If there is only one downward wave, its amplitude should be respectively recorded in the
amplitude of Q wave and S wave.
3. ST segment
Take above baseline of QRS complex as the ST baseline. Calculate the differences between the
ST baseline and the points at 40ms and 60ms after the end point of QRS complex, and calculate
the average value of these two differences, the average value is the amplitude of ST segment.
4. T-wave
Calculate the average value of the data 20-50ms after the end point of T wave, and
average this value with the QRS baseline in 2, then use the result as the baseline of T wave. Find
the max value between the start point and end point of T wave, the difference between the max
value and the baseline would be the amplitude of T wave.
5. Recognition of minimum wave
The minimum wave can be recognized by the algorithm according to the requirement of
IEC60601-2-51:2003 Medical electrical equipment - Part 2-51: Particular requirements for safety,
including essential performance, of recording and analysing single channel and multichannel
electrocardiographs, Annex GG, Clause GG.5 Definition of waveforms, measurement of
minimum waves. The wave that meet the following conditions is the minimum wave that can be
recognized by the algorithm.
1
）
The signal part under consideration shows clearly two opposite slopes with at least one
turning point in between;
2
）
The signal part under consideration deviates at least 30μV from the reference level for
a duration of at least 6ms;
3
）
The minimum observable duration of wave under consideration is 12ms and amplitude
≥30μV.
3.4 Calculation after intervals determination
The following parameters are determined according to the requirement of
IEC60601-2-51:2003 Medical electrical equipment - Part 2-51: Particular requirements for
safety, including essential performance, of recording and analysing single channel and
multichannel electrocardiographs, Annex GG Definitions and rules for the measurement of
ELECTROCARDIOGRAMS
.
No.
Parameter
Calculation
1
HR
60 / RR
2
PR-interval
Qs
- Ps
③
3
P-duration
Pe
④
- Ps
③
4
QRS-duration
Se
⑤
- Qs
