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We present a novel method to detect proximal volume changes based on the impedance plethysmogram (IPG) measured from limb to limb with two electrode pairs symmetrically placed at distal areas of the upper or the lower limbs. Since the measurement is sensitive to changes along the whole current path, this method allows us to detect changes in arteries that are more proximal to the torso than the measurement sites. Our results show that the Pulse Arrival Time (PAT) measured from the R peak of the ECG to the hand-to-hand IPG is close to the PAT to the elbow whereas the PAT measured from the R peak of the ECG to the foot-to-foot IPG is close to the PAT to the knee. This opens new avenues for noninvasive cardiovascular measurements based only on electrodes in contact with hands or feet.

This work presents a novel easy-to-use system intended for the fast and noninvasive monitoring of the Lead I electrocardiogram (ECG) signal by using a wireless steering wheel. The system uses a dual ground electrode configuration connected to a low-power analog front-end to reduce 50/60 Hz interference and it is able to show a stable ECG signal with good enough quality for monitoring purposes in less than 5 s. A novel heart rate detection algorithm based on the continuous wavelet transform has been implemented, which is specially designed to be robust against the most common sources of noise and interference present when acquiring the ECG in the hands, i.e., electromyographic (EMG) noise and baseline wandering. The algorithm shows acceptable performance even under non-ordinary high levels of EMG noise and yields a positive predictivity value of 100.00% and a sensitivity of 99.75% when tested in normal use with subjects of different age, gender, and physical condition. [ABSTRACT FROM PUBLISHER]

This paper describes the circuits and signal processing techniques that convert an electronic bathroom scale intended for bioimpedance analysis (BIA) into a compact system to acquire the electrocardiogram (ECG), the ballistocardiogram (BCG), and the impedance plethysmogram (IPG) using only plantar measurements. The signal processing methods proposed rely on the higher quality of the IPG as compared to the ECG and BCG and they enhance the signal-to-noise ratio (SNR) of these two signals, which otherwise could be too poor in non-controlled environments. The system is suitable for long-term periodic monitoring of cardiovascular function.

Time intervals measured between the electrocardiogram (ECG), the photoplethysmogram (PPG) or the impedance plethysmogram (IPG), have long been used to noninvasively assess cardiovascular function. Recently, the ballistocardiogram (BCG) has been proposed as an alternative physiological signal to be used in time interval measurements for the same purpose. In this work, we study the behavior of the RJ interval, defined as the time between the R wave of the electrocardiogram (ECG) and the J wave of the BCG, under fast pressure changes induced by paced respiration and tracked by a beat-to-beat blood pressure (SBP and DBP) waveform monitor. The aim of this work is to gain a deeper understanding of these newly proposed time intervals and to further assess their usefulness to determine cardiovascular performance.

The Driven-Right-Leg (DRL) circuit has been used for about 50 years to reduce interference due to common-mode voltage in biopotential amplifiers in scenarios that range from fixed equipment supplied from power lines to battery-supplied ambulatory monitors, and for systems that use gelled, dry, textile, and capacitive electrodes. However, power-line interference models predict that for isolation amplifiers, currently mandated by safety standards, power-line interference can often couple mostly in differential mode rather than in common mode. In this work we analyze the effect of the DRL circuit in different ECG leads to elucidate its actual effect on power-line interference reduction. It turns out that that the DRL circuit, which effectively reduces common-mode interference, affects differential-mode interference in an unpredictable way and can increase interference.

This paper describes a novel method to estimate pulse arrival time (PAT) from the electrocardiogram (ECG) and the impedance plethysmogram (TPG) obtained by using a compact and easy-to-use handheld device with only four electrodes. A proof-of-concept has been carried out where PAT values obtained with the proposed device have been compared to PAT values measured between the ECG and the photoplethysmogram (PPG) during three experiments of paced respiration to induce controlled PAT changes. The results show that both methods yield equivalent PAT values in within ± 7 ms (95 % confidence interval), which is less than typical deviations reported for common PAT measurements.