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Systematic variability in ICG recordings results in ICG complex subtypes – steps towards the enhancement of ICG characterization


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Fig. 1

Typical model of dZ/dt waveform recorded simultaneously with an ECG signal. Each signal is marked by characteristic points.
Typical model of dZ/dt waveform recorded simultaneously with an ECG signal. Each signal is marked by characteristic points.

Fig. 2

Electrode positions. a) Electrode positions for measurements obtained with Respimon. b) Electrode positions for measurements obtained with the Z-RPI device.
Electrode positions. a) Electrode positions for measurements obtained with Respimon. b) Electrode positions for measurements obtained with the Z-RPI device.

Fig. 3

Flowchart of the data processing stages.
Flowchart of the data processing stages.

Fig. 4

Observed waveform morphology changes (ABEXYOZ types) of the dZ/dt signal.
Observed waveform morphology changes (ABEXYOZ types) of the dZ/dt signal.

Fig. 5

Distribution of ABEXYOZ complexes with different morphologies. a) Order of percentages of ABEXYOZ complexes, from the most to the least abundant. b) Percentage of ABEXYOZ complexes.
Distribution of ABEXYOZ complexes with different morphologies. a) Order of percentages of ABEXYOZ complexes, from the most to the least abundant. b) Percentage of ABEXYOZ complexes.

Fig. 6

Five consecutive ABEXYOZ complexes with different morphologies.
Five consecutive ABEXYOZ complexes with different morphologies.

Fig. 7

Total percentage of missing points in both groups.
Total percentage of missing points in both groups.

Characteristic points of the dZ/dt signal.

The pointsDescription
AAtrial contraction
BAortic valve opening, which is often calculated as a 15% response from the baseline [14]. The B point may also be calculated from an equation that relates the R peak of the electrocardiography (ECG) signal and the E peak of the dZ/dt signal; RB = 1.233RE -0.0032RE2 - 31.59 [11].
E (or C)Maximum amplitude of dZ/dt from the baseline (dZ/dtmax). It represents the maximum aortic flow.
XAortic valve closing, which is calculated as the first turning point valley after the E point (d1) or the lowest minimum after the E point (d2) [22]. In the time domain, aortic valve closing occurs at the end of the T wave of the ECG signal.
YPulmonic valve closing. It is the minimum notched between the X and O points [6].
OMitral valve opening, the maximum positive point after the E wave [6].
ZMitral regurgitation, which is the minimum notch after the O point [6].

Percentage of missing points of each characteristic point in each volunteer for both groups

Group 1Group 2
V 1V 2V 3V 4V 5V 1V 2V 3V 4V 5
A, B, E (%)21.307.635.706.349.500.014.107.700.000.0
X (%)23.579.397.39796.613.664.281.746.672.0
Y, O, Z (%)25.668.0100.098.5100.097.346.280.098.797

Hemodynamic parameters calculated using ICG characteristic points.

ParametersDescriptionCalculation
PEPPre-ejection periodThe Q-B segment is required.
ET (or LVET)Ventricular ejection timeThe X-B segment is required.
IVRTIsovolumic relaxation timeThe X-O segment is required.
FTVentricular filling timeThe Y-Z segment is required.
SVStroke volume; the volume of blood ejected from the leftBoth the E point and X-B are required [8].
ventricular in one cycleSV=VCEZ0ET$SV={{V}_{C}}\sqrt{\frac{E}{{{Z}_{0}}}}\,\text{ET}$
COAmount of blood pumped during 1 min [8]CO = SV × HR (2)
Heather indexCardiac contractility index is the ratio between theNoted E point and the Q-E time interval.
maximum amplitude of the dZ/dt signal.HeatherIndex=EQE$\text{Heather}\,\,\text{Index}=\frac{E}{\left( \text{Q}-E \right)}$

Percentage of ABEXYOZ complexes contained in each recording per volunteer with the average heart-rate (mean ± SD) for group 2

Waveform Group type 2012345uHR
V 1-86.402.702.708.1--52 ± 4
V 229.406.423.010.215.301.214.175 ± 5
V 307.610.712.335.326.1-07.666 ± 7
V 4-53.401.328.716.4--69 ± 4
V 502.225.8-10.161.8--87 ± 4

Characteristic pattern of ABEXYOZ waveforms

ABEXYOZ sDescription of ABEXYOZ complex
ABEXYOZ 0Typical ABEXYOZ complex of the dZ/dt waveform containing all characteristic ICG points
ABEXYOZ 1ABEXYOZ complex of the dZ/dt waveform with X but without YOZ are unidentified in one slope
ABEXYOZ 2ABEXYOZ complex of the dZ/dt waveform with typical characteristic points, except the X point, which is a not a clear X (noted X2)
ABEXYOZ 3ABEXYOZ complex of the dZ/dt waveform with an unpronounced X point (X2) and no well-defined YOZ points
ABEXYOZ 4ABEXYOZ complex of the dZ/dt waveform without well-defined XYOZ points that are almost time contained in one slope after the E wave
ABEXYOZ 5The ABEXYOZ complex of the dZ/dt waveform that have all of the typical characteristic points, except the X point, which may be a true X or X2, and the dZ/dt waveform has a skirt shape.
ABEXYOZ uThe ABEXYOZ complex of the dZ/dt waveform that is characterized by a high percentage of noise or missing points

Percentage of ABEXYOZ complexes in each recording per volunteer with the average heart-rate (mean ± SD) for group 1

Waveform for group type 1012345uHR
V 172.304.202.1---21.255 ± 5
V 211.309.415.041.509.405.607.560 ± 3
V 3-02.7-08.253.4-35.676 ± 5
V 401.501.5--90.6-06.266 ± 2
V 5-03.4--47.1-49.490 ± 6
eISSN:
1891-5469
Sprache:
Englisch
Zeitrahmen der Veröffentlichung:
Volume Open
Fachgebiete der Zeitschrift:
Technik, Bioingenieurwesen, Biomedizinische Elektronik, Biologie, Biophysik, Medizin, Biomedizinische Technik, Physik, Spektroskopie und Metrologie