94th Hospital of Peoples Liberation Army of China

Nanchang, China

94th Hospital of Peoples Liberation Army of China

Nanchang, China
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Kuang M.-X.,Nanchang University | Xiao Q.-J.,94th Hospital of Peoples Liberation Army of China | Cui C.-Y.,Nanchang University | Kuang N.-Z.,Nanchang University | And 2 more authors.
Annals of Biomedical Engineering | Year: 2010

The purpose of this study is to investigate the mechanism of the formation for thoracic impedance change. On the basis of Ohm's law and the electrical field distribution in the cylindrical volume conductor, the formula about the thoracic impedance change are deduced, and they are demonstrated with the model experiment. The results indicate that the thoracic impedance change caused by single blood vessel is directly proportional to the ratio of the impedance change to the basal impedance of the blood vessel itself, to the length of the blood vessel appearing between the current electrodes, and to the basal impedance between two detective electrodes on the chest surface, while it is inversely proportional to the distance between the blood vessel and the line joining two detective electrodes. The thoracic impedance change caused by multiple blood vessels together is equal to the algebraic addition of all thoracic impedance changes resulting from the individual blood vessels. That is, the impedance changes obey the principle of adding scalars in the measurement of the electrical impedance graph. The present study can offer the theoretical basis for the waveform reconstruction of Impedance cardiography (ICG). © 2010 Biomedical Engineering Society.


Kuang N.-Z.,Nanchang University | Xiao Q.-J.,94th Hospital of Peoples Liberation Army of China | He B.-Q.,Nanchang Institute of Technology | Fu J.-J.,Nanchang Institute of Technology | Kuang M.-X.,Nanchang University
Cardiology Journal | Year: 2014

Background: Many measurements of thoracic impedance graph show that the small C wave and big O wave appear often for patients with cardiac insufficiency, and the O/C ratio is bigger. And for the normal body, especially a younger one, the bigger O wave may also appear. But since the amplitude of the C wave of a normal body is bigger, the O/C ratio is smaller. The aim of the present paper is to investigate the formation mechanism of the normal and abnormal O waves in thoracic impedance graph. Methods and Results: The thoracic mixed impedance changes are measured with 6 leads consisting of 15 electrodes. The impedance change components for the aorta (AO), blood vessel in left lung (PL), blood vessel in right lung (PR), left ventricle (LV) and right ventricle (RV) are separated from thoracic mixed impedance changes by means of establishing and solving the thoracic impedance equations. The amplitudes of the O and C waves of various impedance change components are measured for 50 normal healthy adults and 34 patients with cardiac insufficiency. The formation mechanism of normal and abnormal O waves in thoracic impedance graph is analyzed using the superposition of the O waves of the above impedance change components. Detection subjects are 50 healthy adults and 34 hospital patients with cardiac insufficiency. (1) Thoracic impedance graph: The O/C ratios of the normal group are significantly smaller than that of the abnormal group, p < 0.001. The O wave of first lead (E1-E1') is significantly bigger than that of leads 4 and 5 (E4-E4' and E5-E5') in the normal group, p < 0.001. (2) The impedance change component: The O waves of the AO, PL, and PR are significantly smaller than that of the LV and RV in the normal group, p < 0.001. The O wave and O/C of the AO, PL and PR of normal group are significantly smaller than that of the abnormal group, p < 0.001. Conclusions: The O wave of the thoracic impedance graph is formed due to the superposition of the O waves of the impedance change components for the aorta, blood vessels in lung and ventricles. © 2014 Via Medica.


Ming-Xing K.,Nanchang University | Qiu-Jin X.,94th Hospital of Peoples Liberation Army of China | Nan-Zhen K.,Nanchang University | Chao-Ying C.,Nanchang University | Ai-Rong H.,Nanchang University
Medical Physics | Year: 2011

Purpose: The aim of the present study is to separate the impedance change components of the blood vessels and ventricles in thorax from the mixed impedance signals detected on the chest surface. Methods: The mixed impedance signals on the chest surface are measured with a 15 electrode lead system. The thoracic impedance equations are established and solved iteratively with the algebraic reconstructed technique. Experiments were performed on 80 healthy, otherwise normal, adults. Results: Five impedance change components for the aorta (AO), blood vessel in left lung (PL), blood vessel in right lung (PR), left ventricle (LV), and right ventricle (RV) are separated from the mixed impedance signals. The experiments show that the main waveform of the ventricular components LV and RV is contrary to that of the vascular components AO, PL, and PR, and the negative peak point of the waveform graphs of LV and RV are in phase with the second cardiac sound (S2). The waveform graphs of various components correspond with the physiological activities of the heart and blood vessels in a cardiac cycle. The statistical results for 80 normal adults show that the amplitude of AO is the largest and that of PL and PR is the next, while that of LV and RV is the smallest. There are significant differences between them (P 0.01). Conclusions: The mathematical model and the measurement method for the separation in the present paper are feasible. © 2011 American Association of Physicists in Medicine.


Qiu-Jin X.,94th Hospital of Peoples Liberation Army of China | Zhen W.,94th Hospital of Peoples Liberation Army of China | Ming-Xing K.,94th Hospital of Peoples Liberation Army of China | Ping W.,94th Hospital of Peoples Liberation Army of China | And 2 more authors.
Medical Physics | Year: 2012

Purpose: The aim of the present study is to investigate an impedance change equation suited with the measurement of the impedance cardiograph (ICG). Methods: Based on a parallel impedance model and Ohm's law, an impedance change equation differed from Nyboer's equation is deduced. It is verified with the experiments of the impedance cardiography in 100 healthy adults. Results: This equation shows that the thoracic impedance change (Z) is directly proportional to the value of the volume change (V) of the blood vessel, to the ratio of the basic impedance to the body height (Z 0/H), while it is inversely proportional to the square of the chest circumference (C t 2). These are supported by the experimental results in the measurement of the ICG. Conclusions: The equation proposed in the present paper is coincident with the actual condition in the measurement of the ICG. © 2012 American Association of Physicists in Medicine.


PubMed | 94th Hospital of Peoples Liberation Army of China
Type: Journal Article | Journal: Cardiology journal | Year: 2014

Many measurements of thoracic impedance graph show that the small C wave and big O wave appear often for patients with cardiac insufficiency, and the O/C ratio is bigger. And for the normal body, especially a younger one, the bigger O wave may also appear. But since the amplitude of the C wave of a normal body is bigger, the O/C ratio is smaller. The aim of the present paper is to investigate the formation mechanism of the normal and abnormal O waves in thoracic impedance graph.The thoracic mixed impedance changes are measured with 6 leads consisting of 15 electrodes. The impedance change components for the aorta (AO), blood vessel in left lung (PL), blood vessel in right lung (PR), left ventricle (LV) and right ventricle (RV) are separated from thoracic mixed impedance changes by means of establishing and solving the thoracic impedance equations. The amplitudes of the O and C waves of various impedance change components are measured for 50 normal healthy adults and 34 patients with cardiac insufficiency. The formation mechanism of normal and abnormal O waves in thoracic impedance graph is analyzed using the superposition of the O waves of the above impedance change components. Detection subjects are 50 healthy adults and 34 hospital patients with cardiac insufficiency. (1) Thoracic impedance graph: The O/C ratios of the normal group are significantly smaller than that of the abnormal group, p < 0.001. The O wave of first lead (E-E) is significantly bigger than that of leads 4 and 5 (E-E and E-E) in the normal group, p < 0.001. (2) The impedance change component: The O waves of the AO, PL, and PR are significantly smaller than that of the LV and RV in the normal group, p < 0.001. The O wave and O/C of the AO, PL and PR of normal group are significantly smaller than that of the abnormal group, p < 0.001.The O wave of the thoracic impedance graph is formed due to the superposition of the O waves of the impedance change components for the aorta, blood vessels in lung and ventricles.

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