Heart Rate Detection from Plantar Bioimpedance Measurements

• Published in: 2006 International Conference of the IEEE Engineering in Medicine and Biology Society Vol. 2006; pp. 5113 - 5116
• Main Authors: Landaeta, R.G., Casas, O., Pallas-Areny, R.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States IEEE 2006
• Subjects: Amplifiers, Electronic; Arteries - pathology; Bioimpedance; Biosensors; Blood Flow Velocity; Cardiography, Impedance - instrumentation; Cardiography, Impedance - methods; Electric Capacitance; Electric Impedance; Electrocardiography; Electrodes; Electrophysiology - instrumentation; Electrophysiology - methods; Equipment Design; Heart Rate; Heart rate detection; Heart rate measurement; home health care; Humans; Medical services; Performance analysis; Performance evaluation; Plantar bioimpedance; Sensitivity and Specificity; Sensor systems; Signal Processing, Computer-Assisted; synchronous sampling
• ISBN: 9781424400324; 1424400325
• ISSN: 1557-170X
• DOI: 10.1109/IEMBS.2006.260822

The heart rate is a basic health indicator, useful in both clinical measurements and home health care. Current home care systems often require the attachment of electrodes or other sensors to the body, which can be cumbersome to the patient. Moreover, some measurements are sensitive to movement artifacts, are not user-friendly and require a specialized supervision. In this paper, a novel technique for heart rate measurement for a standing subject is proposed, which is based on plantar bioimpedance measurements, such as those performed by some bathroom weighting scales for body composition analysis. Because of the low level of heart-related impedance variations, the measurement system has a gain of 1400. We have implemented a fully differential AC amplifier with a common-mode rejection ratio (CMRR) of 105 dB at 10 kHz. Coherent demodulation based on synchronous sampling yields a signal-to-noise ratio (SNR) of 55 dB. The system has a sensitivity of 1.9 V/Omega. The technique has been demonstrated on 18 volunteers, whose bioimpedance signal and ECG were simultaneously measured to validate the results. The average cross-correlation coefficient between the heart rates determined from these two signals was 0.998 (std. dev. 0.001)