Reduction in the Motion Artifacts in Noncontact ECG Measurements Using a Novel Designed Electrode Structure.

A noncontact ECG is applicable to wearable bioelectricity acquisition because it can provide more comfort to the patient for long-term monitoring. However, the motion artifact is a significant source of noise in an ECG recording. Adaptive noise reduction is highly effective in suppressing motion artifact, usually through the use of external sensors, thus increasing the design complexity and cost. In this paper, a novel ECG electrode structure is designed to collect ECG data and reference data simultaneously. Combined with the adaptive filter, it effectively suppresses the motion artifact in the ECG acquisition. This method adds one more signal acquisition channel based on the single-channel ECG acquisition system to acquire the reference signal without introducing other sensors. Firstly, the design of the novel ECG electrode structure is introduced based on the principle of noise reduction. Secondly, a multichannel signal acquisition circuit system and ECG electrodes are implemented. Finally, experiments under normal walking conditions are carried out, and the performance is verified by the experiment results, which shows that the proposed design effectively suppresses motion artifacts and maintains the stability of the signal quality during the noncontact ECG acquisition. The signal-to-noise ratio of the ECG signal after noise reduction is 14 dB higher than that of the original ECG signal with the motion artifact.

Home use of a compact, 12­lead ECG recording system for newborns.

BACKGROUND: An easy-to-operate ECG recorder should be useful for newborn screening for heart conditions, by health care workers - or parents. We developed a one-piece electrode strip and a compact, 12­lead ECG recorder for newborns. METHOD: We enrolled 2582 newborns in a trial to assess abilities of parents to record a 12­lead ECG on their infants (2-4 weeks-old). Newborns were randomized to recordings by parents (1290) or our staff (1292 controls). Educational backgrounds of parents varied, including 64% with no more than a high school diploma. RESULTS: For newborns randomized to parent recorded ECGs, 94% of parents completed a 10-minute recording. However, 42.6% asked for verbal help, and 12.7% needed physical help. ECG quality was the same for recordings by parents versus staff. CONCLUSIONS: By use of a one-piece electrode strip and a compact recorder, 87% of parents recorded diagnostic quality ECGs on their newborn infants, with minimal assistance.

Electrical performance of PEDOT:PSS-based textile electrodes for wearable ECG monitoring: a comparative study.

BACKGROUND: Wearable textile electrodes for the detection of biopotentials are a promising tool for the monitoring and early diagnosis of chronic diseases. We present a comparative study of the electrical characteristics of four textile electrodes manufactured from common fabrics treated with a conductive polymer, a commercial fabric, and disposable Ag/AgCl electrodes. These characteristics will allow identifying the performance of the materials when used as ECG electrodes. The electrodes were subjected to different electrical tests, and complemented with conductivity calculations and microscopic images to determine their feasibility in the detection of ECG signals. METHODS: We evaluated four electrical characteristics: contact impedance, electrode polarization, noise, and long-term performance. We analyzed PEDOT:PSS treated fabrics based on cotton, cotton-polyester, lycra and polyester; also a commercial fabric made of silver-plated nylon Shielde® Med-Tex P130, and commercial Ag/AgCl electrodes. We calculated conductivity from the surface resistance and, analyzed their surface at a microscopic level. Rwizard was used in the statistical analysis. RESULTS: The results showed that textile electrodes treated with PEDOT:PSS are suitable for the detection of ECG signals. The error detecting features of the ECG signal was lower than 2% and the electrodes kept working properly after 36 h of continuous use. Even though the contact impedance and the polarization level in textile electrodes were greater than in commercial electrodes, these parameters did not affect the acquisition of the ECG signals. Fabrics conductivity calculations were consistent to the contact impedance.

The role of acrylic acid impurity as a sensitizing component in electrocardiogram electrodes.

BACKGROUND: Allergic contact dermatitis caused by (meth)acrylates is well known, both in occupational and in non-occupational settings. Contact hypersensitivity to electrocardiogram (ECG) electrodes containing (meth)acrylates is rarely reported. OBJECTIVE: To report the first case of contact dermatitis caused by acrylic acid impurity in ECG electrodes. MATERIALS AND METHODS: Patch tests were performed with separate components of electrodes and some (meth)acrylates. This was followed by high-performance liquid chromatography of electrode hydrogel. RESULTS: The patient was contact-allergic to electrode hydrogel but not to its separate constituents. Positive reactions were observed to 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxypropyl methacrylate (2-HPMA) and ethyleneglycol dimethacrylate (EGDMA). Subsequent analysis showed that the electrode hydrogel contained acrylic acid as an impurity. The latter was subsequently patch tested, with a positive result. CONCLUSION: The sensitization resulting from direct contact with ECG electrodes was caused by acrylic acid, present as an impurity in ECG electrodes. Positive reactions to 2-HEMA, 2-HPMA and EGDMA are considered to be cross-reactions.

Sensitivity of CIPS-computed PVC location to measurement errors in ECG electrode position: the need for the 3D camera.

BACKGROUND: The Cardiac Isochrone Positioning System (CIPS) is a non-invasive method able to localize the origins of PVCs, VT and WPW from the 12 lead ECG. The CIPS model integrates a standard 12-lead ECG with an MRI derived model of the heart, lungs, and torso in order to compute the precise electrical origin of a PVC from within the myocardium. To make these calculations, CIPS uses virtually represented ECG electrode positions. These virtual electrode positions, however, are currently assumed to represent the standard 12 lead positions in the model without taking into account the actual, anatomical locations on a patient. The degree of error introduced into the CIPS model by movement of the virtual electrodes is unknown. Therefore, we conducted a model-based study to determine the sensitivity of CIPS to changes in its virtually represented ECG electrode positions. METHODS: Previously, CIPS was tested on 9 patients undergoing PVC ablation, producing a precise myocardial PVC location for each patient. These initial results were used as controls in two different simulation experiments. The first moved all virtual precordial leads in CIPS simultaneously up and down to recalculate a PVC origin. The second moved each virtual precordial lead individually, using 8 points on multiple concentric circles of increasing radius to recalculate a PVC origin. The distance of the newly calculated PVC origin from the control origin was used as a metric. RESULTS: Moving either all electrodes simultaneously or each V1-6 precordial electrode independently resulted in non-linear and unpredictable shifts of the CIPS-computed PVC origin. Simultaneously moving all V1-6 precordial electrodes by 10mm increments produced a shift in CIPS-computed PVC origin between 0 and 62mm. Independently moving an electrode, a shift of more than 10mm resulted in an unpredictable CIPS-computed PVC origin relocation between 0 and 40mm. The effect of moving the virtual electrodes on CIPS modeling more pronounced the closer the virtual electrode was positioned to the actual PVC origin. CONCLUSIONS: Slight changes in the virtual positions of the V1-6 precordial electrodes produce marked, non-linear and unpredictable shifts in the CIPS-computed PVC origin. Thus, any variation in the physical ECG electrode placement on a patient can result in significant error within the CIPS model. These large errors would make CIPS useless and underscore the need for accurate, patient specific measurement of electrode position relative to the patient specific torso geometries. A potential solution to this problem could be the introduction of a 3D camera to incorporate accurate measurement of physical electrode placement into the CIPS model. Since the 3D camera software integrates the 3D imaged position of the electrode with the MRI derived torso model, it is conveniently incorporated in the next generation CIPS software to decrease the errors in modeled location of the electrodes. Thus, the 3D camera will be the III(rd) component of the CIPS to increase its accuracy in PVC, VT, and WPW localization.

Hydrogels and Carbon Nanotubes: Composite Electrode Materials for Long-Term Electrocardiography Monitoring.

This paper presents methods for developing high-performance interface electrode materials designed to enhance signal collection efficacy during long-term (over 24 h) electrocardiography (ECG) monitoring. The electrode materials are fabricated by integrating commercial ECG liquid hydrogels with carbon nanotubes (CNTs), which are widely utilized in dry-electrode technologies and extensively discussed in the current scientific literature. The composite materials are either prepared by dispersing CNTs within the commercial liquid hydrogel matrix or by encasing the hydrogels in macroscopic CNT films. Both approaches ensure the optimal wetting of the epidermis via the hydrogels, while the CNTs reduce material impedance and stabilize the drying process. The resulting electrode materials maintain their softness, allowing for micro-conformal skin attachment, and are biocompatible. Empirical testing confirms that the ECG electrodes employing these hybrid hydrogels adhere to relevant standards for durations exceeding 24 h. These innovative hybrid solutions merge the benefits of both wet and dry ECG electrode technologies, potentially facilitating the extended monitoring of ECG signals and thus advancing the diagnosis and treatment of various cardiac conditions.

Standardization in Performing and Interpreting Electrocardiograms.

Excellence in recording and interpretation of electrocardiogram (ECG) is a necessity for optimal electrocardiography. This includes data to properly interpret the ECG, including data on age, gender, cardiovascular diagnosis, medications, abnormal laboratory findings (eg, data on electrolytes), and the indications for the electrocardiogram. The ECG needs to be performed by a qualified technician and interpreted by an experienced physician.

Bioinspired, Highly Stretchable, and Conductive Dry Adhesives Based on 1D-2D Hybrid Carbon Nanocomposites for All-in-One ECG Electrodes.

Here we propose a concept of conductive dry adhesives (CDA) combining a gecko-inspired hierarchical structure and an elastomeric carbon nanocomposite. To complement the poor electrical percolation of 1D carbon nanotube (CNT) networks in an elastomeric matrix at a low filler content (∼1 wt %), a higher dimensional carbon material (i.e., carbon black, nanographite, and graphene nanopowder) is added into the mixture as an aid filler. The co-doped graphene and CNT in the composite show the lowest volume resistance (∼100 ohm·cm) at an optimized filler ratio (1:9, total filler content: 1 wt %) through a synergetic effect in electrical percolation. With an optimized conductive elastomer, gecko-inspired high-aspect-ratio (>3) microstructures over a large area (∼4 in.(2)) are successfully replicated from intaglio-patterned molds without collapse. The resultant CDA pad shows a high normal adhesion force (∼1.3 N/cm(2)) even on rough human skin and an excellent cycling property for repeatable use over 30 times without degradation of adhesion force, which cannot be achieved by commercial wet adhesives. The body-attachable CDA can be used as a metal-free, all-in-one component for measuring biosignals under daily activity conditions (i.e., underwater, movements) because of its superior conformality and water-repellent characteristic.

Novel Conductive Carbon Black and Polydimethlysiloxane ECG Electrode: A Comparison with Commercial Electrodes in Fresh, Chlorinated, and Salt Water.

In this study, we evaluated the performance of two novel conductive carbon black (CB) and polydimethlysiloxane (PDMS) bio-potential electrodes, with and without an integrated flexible copper mesh, against commercially available electrodes (Polar(®) textile, Silver-coated textile, and carbon rubber). The electrodes were tested in three types of water (fresh/unfiltered, chlorinated, and salt water). Our testing revealed that our CB/PDMS electrode with integrated copper mesh provided a high-fidelity ECG signal morphologies without any amplitude degradation in all of the types of water tested (N = 10). The non-meshed CB/PDMS electrodes were also subjected to a long-term durability test by the US Navy SCUBA divers during which the electrodes maintained ECG signal quality for a 6 h period of continuous use. The results of a material degradation analysis revealed the CB/PDMS composite material does not exhibit significant changes in physical integrity after prolonged exposure to the test conditions. The newly developed meshed CB/PDMS electrodes have the potential to be used in a wide variety of both dry and wet environments including the challenge of obtaining ECG signals in salt water environments.