Couderc, J.; Beshaw, C.; Xiaodan, N.; Serrano, R.; Casas, J.O.; Pallas-Areny, R.; Rosero, S.; Zareba, W. Annals of Noninvasive Electrocardiology Vol. 22, num. 1, p. 1-11 DOI: 10.1111/anec.12378 Data de publicació: 2017-01 Article en revista
Despite the strong evidence of the clinical utility of QTc prolongation as a surrogate marker of cardiac risk, QTc measurement is not part of clinical routine either in hospital or in physician offices. We evaluated a novel device (“the QT scale”) to measure heart rate (HR) and QTc interval.
The QT scale is a weight scale embedding an ECG acquisition system with four limb sensors (feet and hands: lead I, II, and III). We evaluated the reliability of QT scale in healthy subjects (cohort 1) and cardiac patients (cohorts 2 and 3) considering a learning (cohort 2) and two validation cohorts. The QT scale and the standard 12-lead recorder were compared using intraclass correlation coefficient (ICC) in cohorts 2 and 3. Absolute value of heart rate and QTc intervals between manual and automatic measurements using ECGs from the QT scale and a clinical device were compared in cohort 1.
We enrolled 16 subjects in cohort 1 (8 w, 8 m; 32 ± 8 vs 34 ± 10 years, P = 0.7), 51 patients in cohort 2 (13 w, 38 m; 61 ± 16 vs 58 ± 18 years, P = 0.6), and 13 AF patients in cohort 3 (4 w, 9 m; 63 ± 10 vs 64 ± 10 years, P = 0.9). Similar automatic heart rate and QTc were delivered by the scale and the clinical device in cohort 1: paired difference in RR and QTc were -7 ± 34 milliseconds (P = 0.37) and 3.4 ± 28.6 milliseconds (P = 0.64), respectively. The measurement of stability was slightly lower in ECG from the QT scale than from the clinical device (ICC: 91% vs 80%) in cohort 3.
The “QT scale device” delivers valid heart rate and QTc interval measurements.
"This is the peer reviewed version of the following article: [Ann Noninvasive Electrocardiol 2017;22(1):e12378, DOI: 10.1111/anec.12378], which has been published in final form at [http://onlinelibrary.wiley.com/doi/10.1111/anec.12378/pdf]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."
Despite the strong evidence of the clinical utility of QTc prolongation as a
surrogate marker of cardiac risk, QTc measurement is not part of clinical routine either in hospital
or in physician of
ces. We evaluated a novel device (
“the QT scale”) to measure heart rate (HR)
and QTc interval.
Atrial fibrillation (AF) is a cardiac arrhythmia
characterized by a highly irregular heart rate. It is the
most prevalent arrhythmia in the general population in
the United States and most developed countries, and is
strongly associated with increased morbidity and
mortality from adverse cardiovascular and
cerebrovascular events. Moreover, patients with AF are
correlated with increased healthcare expenditures,
making the burden of AF on society extremely large.
In this proof-of-concept study, we present an
innovative device to be used as a screening tool for AF.
The device consists of a modified electronic scale that is
able to obtain an ECG and analyse it for the presence of
AF. The classification algorithm is based on the RdR map
method that plots RR intervals versus change in RR
After optimizing the algorithm on a learning set of 77
ECGs from 45 patients, the performance of the device
during a blind validation of 76 ECGs from 44 patients
was: accuracy = 83%, sensitivity = 83%, specificity =
83% (N = 76 ECGs). Applying a constraint that each
ECG recording contains a minimum of 7 beats in order to
be eligible for classification, accuracy improved to 89%
(sensitivity = 83%, specificity = 90%, N = 70).
In conclusion, we present an innovative device to
detect AF in a manner that can be implemented into
current physician workflow without increasing the time or
cost of each clinical encounter.
A new technique to measure a capacitor or a capacitive sensor by means of a direct sensor-to-microcontroller interface circuit that does not need a calibration capacitor is proposed. Basically, the measurement process consists of three consecutive steps of charge, discharge and charge of the capacitor under test. A non-linear equation is obtained and solved that is dependent only on known circuit parameters. Experimental results show that it is possible to measure a wide range of capacitor values with a maximum deviation of 2% from the reference value, and that temperature changes from 18 to 70°C yield relative errors below 0.1%. For the lowest measured capacitor range (33 pF-4.7 nF) the uncertainty holds below 1 pF which enables measurement of commercially available capacitive sensors. The main advantage of the proposed technique is cost and space reduction of the final design.
Lopez-Lapeña, O.; Serrano, R.; Casas, J.O. IEEE transactions on instrumentation and measurement Vol. 65, num. 1, p. 222-230 DOI: 10.1109/TIM.2015.2479105 Data de publicació: 2016-01-01 Article en revista
This paper analyzes the energy consumption of
direct interface circuits where the data conversion of a resistive
sensor is performed by a direct connection to a set of digital ports
of a microcontroller (µC). The causes of energy consumption
as well as their relation to the measurement specifications in
terms of uncertainty are analyzed. This analysis yields a tradeoff
between energy consumption and measurement uncertainty,
which sets a design procedure focused on achieving the lowest
energy consumption for a given uncertainty and a measuring
range. Together with this analysis, a novel experimental setup is
proposed that allows one to measure the µC’s timer quantization
uncertainty. An application example is shown where the design
procedure is applied. The experimental results fairly fit the
theoretical analysis, yielding only 5 µJ to achieve nine effective
number of bits (ENOB) in a measuring range from 1 to 1.38 k.
With the same ENOB, the energy is reduced to 1.9 µJ when the
measurement limits are changed to 100 and 138 k.
AC-coupled amplifiers are noisier than dc-coupled amplifiers because of the thermal noise of the resistor(s) in the ac-coupling network and the increased contribution of the amplifier input noise current i(n). Both contributions, however, diminish if the corner frequency f(c) of the high-pass filter observed by the signal is lowered, the cost being a longer transient response. At the same time, the presence of large resistors in the ac-coupling network suggests that the use of FET-input amplifiers will be advantageous because i(n) is smaller than in bipolar amplifiers. However, the noise floor, defined as that for a dc-coupled amplifier, can be larger for FET-input amplifiers because of their higher input voltage noise. Therefore, there is no clear criterion to decide which amplifier type is quieter. In this paper, we propose the quotient between the high-pass frequency of the signal bandwidth (f(L)) and f(c) (K = f(L)/f(c)) as quantitative design parameter to reduce the additional noise contributed by a first-order ac-coupling network as compared with dc coupling. Using this parameter noise is greatly reduced without unnecessarily lengthening the transient response that results from the use of common qualitative design criteria. We demonstrate that relatively large K values yield total noise closer to the noise floor, hence it is better not to determine f(L) at the front amplifier stage but later on in the signal chain. Furthermore, a large K value permits bipolar op-amps to achieve lower noise than FET amplifiers even for capacitive signal sources, provided amplifier biasing is guaranteed.
Aparato de electrocardiogramas (ECG), que obtiene en paralelo las derivaciones bipolares I, II y III del ECG, que comprende únicamente tres o cuatro electrodos: dos electrodos manuales (101, 102) de tamaño y forma para caber íntegramente en cada mano y dos electrodos para los pies: un electrodo izquierdo (100) y un electrodo derecho (105) opcional, de superficie y forma inferior a la planta del pie del usuario.
Los electrodos manuales (101, 102) y el electrodo izquierdo (100) comprenden sendos seguidores de tensión (110, 111, 112) en su conexión con el sistema electrónico (200) de obtención y procesamiento del ECG, mientras que el electrodo derecho (105) puede conectarse a la masa del sistema electrónico (200). Los electrodos manuales (101, 102) pueden ser sendas esferas conductoras y los electrodos para los pies, discos, de forma que tengan sus correspondientes seguidores de tensión (110, 111, 112) dentro de los electrodos correspondientes.
'The RICE-GUARD monitoring system is a tool designed to assist rice-growers in their rice blast management decisions. Rice blast is the most serious disease of cultivated rice. It is caused by the fungus Magnaporthe grisea (Pyricularia oryzae Cav.), which in favourable conditions can produce yield losses of up to 100 %. The fungus affects all the rice-growing regions of the world, including all rice-producing countries in the EU, and it is estimated to cause yearly losses of up to 30 % of the global rice harvest, which would be enough to feed 60 million people.
The intensity of rice blast (incidence and severity of disease) is highly variable and depends on cropping system and climate. All the phases of the disease cycle are driven by the site-specific weather and environmental conditions. Currently, when rice growers see menacing environmental conditions, they spray their fields with fungicide. However, there are not many fungicides that are effective in combating rice blast. As a result, rice is the second largest crop consumer of fungicides in the world, some of them being highly noxious.
This project will develop a wireless sensor network comprised of low-cost measurement nodes that will be capable of transmitting readings of the relevant in-field site-specific environmental variables in real-time to a central server. The systems’ software will combine these data with other relevant cultivation parameters in order to supply up-to-date information to rice growers. The RICE-GUARD monitoring system will enable cultivators to effectively protect their paddy fields and greatly reduce fungicide consumption, reducing environmental impact, increasing food security and crop yields.'
'Rice is the main crop in wet areas such as river deltas and is an essential tool in Europe in managing protected ecosystems. Irrigation water is a key factor in the production of rice and water quality has a major impact on crop yield as a result of tolerance of rice to factors such as dissolved salts. Rice is more water consuming than many other crops: in continuous flooding cultivation it takes about 6 times the water required by wheat. Due to increased water use in coastal areas, the sea intrudes the water table and seawater floods nearby fields during storms in the Mediterranean area. The result is increased water salinity, which reduces yield in rice crops and increases soil salinity. Nowadays, water condition is for the most part assessed by visual inspection of the crops and, when excess water salinity is suspected, fields are irrigated by flooding them. In areas where water salinity is endemic, rice paddies are continuously irrigated with river water to reduce water salinity. This is a remedial solution that requires enormous volumes of water and considerable energy to pump water.
Water salinity can be accurately determined by measuring its electrical conductivity (EC). Measuring EC at the water inlet and outlet of each paddy field can help in monitoring the “washing” effect of irrigation. Moreover, measuring EC at points far from water inlets and outlets can help in assessing water salinity in a given paddy field and at different depths in drainage channels can help in managing water salinity in larger areas. This project will develop a wireless sensor network comprised of low-cost EC measurement nodes and an autonomous power supply based on energy harvesting, that will be capable of transmitting readings in real-time to a central server. This data will enable cultivators to effectively manage and protect of their paddy fields and greatly reduce flood water consumption.'
Gomez-Clapers, J.; Serrano, R.; Casanella, R.; Pallas-Areny, R. Annual International Conference of the IEEE Engineering in Medicine and Biology Society p. 4780-4783 Data de presentació: 2011-09-01 Presentació treball a congrés
Método y aparato para obtener varias derivaciones simultáneas del electrocardiograma.
En esta patente de invención se describen un método y un aparato para obtener simultáneamente varias derivaciones estándar del electrocardiograma (ECG) de una persona plantada sobre una superficie o sentada y con los pies apoyados sobre una superficie, y cuyas manos, en cualquiera de los dos casos, establecen contacto con sendos electrodos. La superficie sobre la que está plantado el paciente o en la que se apoyan sus pies incluye dos zonas conductoras que actúan como electrodos, uno para cada pie. Todos los electrodos están conectados al cuerpo principal del aparato, que para mayor comodidad puede formar una unidad con la superficie con la que están en contacto los pies de la persona de la cual se desea obtener el ECG, o alternativamente dicha superficie y los electrodos de las manos forman una unidad que se puede conectar a un electrocardiógrafo convencional.
Gomez-Clapers, J.; Serrano, R.; Casanella, R.; Pallas-Areny, R. Annual International Conference of the IEEE Engineering in Medicine and Biology Society Vol. 2011, p. 4780-4783 Data de publicació: 2011 Article en revista
Bruno, J.; Ernestro, S.; Serrano, R.; Feixas, T.; Núria, C.; Camacho, M.; Riu, P.J. Archivos de bronconeumología Vol. 44, num. 8, p. 408-412 DOI: 10.1016/S0300-2896(08)72103-3 Data de publicació: 2008-08 Article en revista