Assessment of cardiac time intervals by wavelet transform of the impedance cardiogram

Focused impedance measurements (FIM) are used in several fields, and address the problem of measuring the volume impedance of an object within a volume conductor. Several electrode configurations are possible, and these have different properties. Sensitivity fields of four configurations have been investigated. We present one new development of an existing FIM configuration, and we made finite element models of the configurations to analyse and compare them both graphically and numerically. The models developed have a variable-sized mesh that allows us to build complex models that fit easily in computer memory. We found that one configuration in particular, FIM4, was superior to the others in most aspects. We also analysed the effects of very high sensitivities in and under the electrodes. We found that even if the sensitivity is very high under the electrodes, the effects of inhomogeneities were not as high as one might expect.

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“…ICG measurements have also been used to extract timing information, and work in this area is ongoing [28].…”

Section: Impedance Cardiography and Impedance Catheter Measurementsmentioning

confidence: 99%

Comparison of four different FIM configurations—a simulation study

et al. 2014

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“…Another group of methods utilizes the time–frequency distribution of the signal [ 18 ] and the wavelet decomposition. Within these approaches, the characteristic points are either identified as the singularities of the wavelet transform [ 19 , 20 , 21 , 22 ] or inferred from the distribution of wavelet coefficients [ 23 , 24 ]. The majority of them struggle, however, with a high computational complexity or a large sensitivity to the artifacts.…”

Section: Introductionmentioning

confidence: 99%

A New Method of Identifying Characteristic Points in the Impedance Cardiography Signal Based on Empirical Mode Decomposition

Trybek

Sobotnicka

Wawrzkiewicz-Jałowiecka

et al. 2023

Sensors

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The accurate detection of fiducial points in the impedance cardiography signal (ICG) has a decisive impact on the proper estimation of diagnostic parameters such as stroke volume or cardiac output. It is, therefore, necessary to find an algorithm that is able to assess their positions with great precision. The solution to this problem is, however, quite challenging with regard to the high sensitivity of the ICG technique to the noise and varying morphology of the acquired signals. The aim of this study is to propose a novel method that allows us to overcome these limitations. The developed algorithm is based on Empirical Mode Decomposition (EMD)—an effective technique for processing and analyzing various types of non-stationary signals. We find high correlations between the results obtained from the algorithm and annotated by an expert. This, in turn, implies that the difference in estimation of the diagnostic-relevant parameters is small, which suggests that the method can automatically provide precise clinical information.

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“…Many noninvasive hemodynamic monitoring techniques, such as impedance cardiography, arterial pressure-based CO (APCO), volume clamp method, and pulse wave transit time (PWTT) method, have been developed and studied recently [7][8][9]. Among these methods, the estimated continuous cardiac output (esCCO) system, a technique based on the PWTT method, can noninvasively and continuously monitor CO.…”

Section: Introductionmentioning

confidence: 99%

Comparison of parameter types for the calibration of noninvasive continuous cardiac output monitoring of patients undergoing lumbar spinal surgery in the prone position

Lee¹,

Lee²,

Lee³

et al. 2023

THC

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BACKGROUND: Cardiac output (CO) decreases on reversing the patient’s position to the prone position. Estimated continuous cardiac output (esCCO) systems can noninvasively and continuously monitor CO calibrated by patient information or transesophageal echocardiogram (TEE). OBJECTIVE: To compare the accuracy, precision, and trending ability of two calibration methods of CO estimation in patients in prone position. METHODS: The CO estimates calibrated by TEE (esT) and patient information (esP) of 26 participants were included. CO was collected at four time points. The accuracy and precision of agreement were evaluated using the Bland-Altman method. A four-quadrant plot was used for trending ability analysis. RESULTS: The bias between esP and TEE and between esT and TEE was 0.2594 L/min (95% limits of agreement (LoA): -1.8374 L/min to 2.3562 L/min) and 0.0337 L/min (95% LoA: -0.7381 L/min to 0.8055 L/min), respectively. A strong correlation was found between ΔesP and ΔTEE (p< 0.001, CCC = 0.700) and between ΔesT and ΔTEE (p< 0.001, CCC = 0.794). The concordance rates between ΔesP and ΔTEE and between ΔesT and ΔTEE were 91.9% and 97.1%, respectively. CONCLUSION: Despite limited accuracy and precision, esP showed acceptable trending ability. The trending ability of esCCO calibrated by the reference TEE value was comparable with that of TEE.

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Assessment of cardiac time intervals by wavelet transform of the impedance cardiogram

Cited by 6 publications

References 12 publications

Comparison of four different FIM configurations—a simulation study

Comparison of four different FIM configurations—a simulation study

A New Method of Identifying Characteristic Points in the Impedance Cardiography Signal Based on Empirical Mode Decomposition

Comparison of parameter types for the calibration of noninvasive continuous cardiac output monitoring of patients undergoing lumbar spinal surgery in the prone position

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