Development of a wearable multi-frequency impedance cardiography device

Abstract Cardiovascular diseases as well as pulmonary oedema can be early diagnosed using vital signs and thoracic bio-impedance. By recording the electrocardiogram (ECG) and the impedance cardiogram (ICG), vital parameters are captured continuously. The aim of this study is the continuous monitoring of ECG and multi-frequency ICG by a mobile system. A mobile measuring system, based on ‘low-power’ ECG, ICG and an included radio transmission is described. Due to the high component integration, a board size of only 6.5 cm × 5 cm could be realized. The measured data can be transmitted via Bluetooth and visualized on a portable monitor. By using energy-efficient hardware, the system can operate for up to 18 hs with a 3 V battery, continuously sending data via Bluetooth. Longer operating times can be realized by decreased transfer rates. The relative error of the impedance measurement was less than 1%. The ECG and ICG measurements allow an approximate calculation of the heart stroke volume. The ECG and the measured impedance showed a high correlation to commercial devices (r = 0.83, p < 0.05). In addition to commercial devices, the developed system allows a multi-frequency measurement of the thoracic impedance between 5–150 kHz.

[1]  Fernando Seoane,et al.  An analog front-end enables electrical impedance spectroscopy system on-chip for biomedical applications , 2008, Physiological measurement.

[2]  R. Granit.  THE HEART ( Extract from “ Principles and Applications of Bioelectric and Biomagnetic Fields , 2005 .

[3]  K. R. Visser,et al.  Observations on blood flow related electrical impedance changes in rigid tubes , 1976, Pflügers Archiv.

[4]  G. Darovic.  Hemodynamic Monitoring: Invasive and Noninvasive Clinical Application , 1987 .

[5]  G. Cotter,et al.  Impedance cardiography revisited , 2006, Physiological measurement.

[6]  W. Tang,et al.  Measuring impedance in congestive heart failure: current options and clinical applications. , 2009, American heart journal.

[7]  R. Gaw,et al.  The effect of red blood cell orientation on the electrical impedance of pulsatile blood with implications for impedance cardiography , 2010 .

[8]  D P Bernstein,et al.  A new stroke volume equation for thoracic electrical bioimpedance: Theory and rationale , 1986, Critical care medicine.

[9]  Ramon Bragós,et al.  Propagation of Measurement Errors Through Body Composition Equations for Body Impedance Analysis , 2014, IEEE Transactions on Instrumentation and Measurement.

[10]  Ramon Bragós,et al.  Minimal implementation of an AFE4300-based spectrometer for electrical impedance spectroscopy measurements , 2013 .

[11]  Steffen Leonhardt,et al.  The IMPACT shirt: textile integrated and portable impedance cardiography , 2014, Physiological measurement.

[12]  Franklin D. Johnston,et al.  Electrical impedance plethysmography : the electrical resistive measure of the blood pulse volume, peripheral and central blood flow , 1959 .

[13]  Steffen Leonhardt,et al.  Simulation of Continuous Spectroscopic Bioimpedance Measurements for Impedance Cardiography , 2012 .

[14]  Robert Plonsey,et al.  Bioelectromagnetism: Principles and Applications of Bioelectric and Biomagnetic Fields , 1995 .

[15]  H. G. Goovaerts,et al.  A meta-analysis of three decades of validating thoracic impedance cardiography. , 1999, Critical care medicine.

[16]  Leigh C Ward,et al.  Determination of Cole parameters in multiple frequency bioelectrical impedance analysis using only the measurement of impedances , 2006, Physiological measurement.