Abstract:
:Body surface potential maps recorded during catheter pace mapping can facilitate the localization of the site of origin of ventricular tachycardia. In this study, we investigated the value of a realistic computer model of the human ventricular myocardium in generating body surface potential maps as templates for identifying sites of ectopic activation. Our model features an anatomically accurate geometry and an anisotropy due to transmural fibre rotation, that were reconstructed with a spatial resolution of 0.5 mm. It simulates the electrotonic interactions of cardiac cells by solving a nonlinear parabolic partial differential equation, but it behaves as a cellular automaton when the transmembrane potential exceeds the threshold value. We successfully validated our model by comparing the simulated activation sequences--described by isochronal maps, epicardial potential maps and body surface potential maps--with the measured sequences of epicardial and body surface maps reported in the literature. By systematically pacing the left ventricular and right ventricular endocardial surfaces in our ventricular model, we generated a database of 155 QRS-integral maps, which provides a high-resolution reference frame for localizing distinct endocardial pacing sites. This database promises to be a useful tool in improving the performance of catheter pace mapping used in combination with body surface potential mapping. Overall, the results demonstrate that our computer model of the human ventricular myocardium is well suited for complementing a database of QRS-integral maps obtained during clinical pace mapping and can help enhance the efficacy of the ablative treatment of ventricular arrhythmias.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Hren R,Horácek BMdoi
10.1088/0967-3334/18/4/010subject
Has Abstractpub_date
1997-11-01 00:00:00pages
373-400issue
4eissn
0967-3334issn
1361-6579journal_volume
18pub_type
杂志文章abstract::The transthoracic electrical impedance is an important defibrillation parameter, affecting the defibrillating current amplitude and energy, and therefore the defibrillation efficiency. A close relationship between transthoracic impedance and defibrillation success rate was observed. Pre-shock measurements (using low a...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/21/1/318
更新日期:2000-02-01 00:00:00
abstract::The paper presents a method for adaptive decomposition of an electrical bio-impedance (BI) signal into two components: cardiac and respiratory. The decomposition of a BI signal is not a trivial process because of the non-stationarity of the signal components and overlapping of their harmonic spectra. An application sp...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/6/S02
更新日期:2008-06-01 00:00:00
abstract:OBJECTIVE:To quantify the presence of cardiorespiratory interaction in a group of 41 healthy subjects performing a subset of the Ewing test battery. APPROACH:We measure the empirical distribution of the cardiorespiratory coupling time (RI), defined as the time from inspiration onset to R peaks in the ECG. The study pr...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aa9693
更新日期:2017-11-30 00:00:00
abstract::Epidemiological studies have associated the negative effects of sedentary time and sedentary patterns on health indices. However, these studies have used methodologies that do not directly measure the sedentary state. Recent technological developments in the area of motion sensors have incorporated inclinometers, whic...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/11/1887
更新日期:2012-11-01 00:00:00
abstract::There has been a surge of interest in using electrical impedance tomography (EIT) for monitoring regional lung ventilation, however, EIT is an ill-conditioned problem, and errors/noise in the boundary voltages can have an undesirable effect on the quality of the final image. Most EIT systems in clinical usage use seri...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/34/6/659
更新日期:2013-06-01 00:00:00
abstract::Fetal heart rate monitoring is used for pregnancy surveillance in obstetric units all over the world but in spite of recent advances in analysis methods, there are still inherent technical limitations that bound its contribution to the improvement of perinatal indicators. In this work, a previously published wavelet t...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/8/1723
更新日期:2014-08-01 00:00:00
abstract:OBJECTIVE:Tensiomyography (TMG) and myotonometry (MMT) are two novel technologies that measure neuromuscular properties. These two devices measure the stiffness of the soft tissue as well as other variables. The aim of this study is to analyze if there is any correlation between maximal radial displacement (Dm) and Sti...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abcdf4
更新日期:2020-12-31 00:00:00
abstract::Electrical impedance tomography (EIT) image reconstruction is an ill-posed problem requiring maximum measurement precision. Recent EIT systems claim 60 to 80 dB precision. Achieving higher values is hard in practice since measurements must be performed at relatively high frequency, on a living subject, while using com...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/5/S05
更新日期:2006-05-01 00:00:00
abstract::Electrical impedance scanning (EIS) is a kind of potential bio-impedance measurement technology, especially aiding the diagnosis of breast cancer in women. By changing the frequency of the driving signal in turn while keeping the other conditions stable, multi-frequency measurement results on the object can be obtaine...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/7/S07
更新日期:2007-07-01 00:00:00
abstract::In this work, we describe a beat-by-beat method for assessing the clinical utility of pulsatile waveforms, primarily recorded from cardiovascular blood volume or pressure changes, concentrating on the photoplethysmogram (PPG). Physiological blood flow is nonstationary, with pulses changing in height, width and morphol...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/9/1491
更新日期:2012-09-01 00:00:00
abstract::Monitoring the fetal behavior does not only have implications for acute care but also for identifying developmental disturbances that burden the entire later life. The concept, of 'fetal programming', also known as 'developmental origins of adult disease hypothesis', e.g. applies for cardiovascular, metabolic, hyperki...
journal_title:Physiological measurement
pub_type: 杂志文章,评审
doi:10.1088/1361-6579/aa5fca
更新日期:2017-05-01 00:00:00
abstract::The aim of our study was to check the effect of varying blood volume in the chest and gravity on the distribution of ventilation and aeration in the lungs. The change in intrathoracic blood volume was elicited by application of lower body negative pressure (LBNP) of -50 cmH2O. The variation of gravity in terms of hypo...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/26/2/003
更新日期:2005-04-01 00:00:00
abstract:OBJECTIVE:As the global burden of cardiovascular disease increases, proactive cardiovascular healthcare by means of accurate, precise, continuous, and non-invasive monitoring is becoming crucial. However, no current device is able to provide cardiac hemodynamic monitoring with the aforementioned criterion. Electrical i...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abb141
更新日期:2020-10-06 00:00:00
abstract:OBJECTIVE:Observational studies suggest that obesity might have a Mendelian origin, but it is not clear if gene expression patterns observed in obese subjects are secondary to genetic traits or not. APPROACH:Here we test a transcriptomic signature of obesity previously identified by our group on a large cohort of twin...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aab85a
更新日期:2018-04-26 00:00:00
abstract::A finite difference model of the human thorax with 113,400 control volumes (nodes) based on ECG gated MRI images was used to evaluate the Sheffield DAS-01P EIT system. Sixteen simulated electrode positions equally spaced around the thorax model at approximately the fourth intercostals space level were selected. Pairs ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/24/2/357
更新日期:2003-05-01 00:00:00
abstract::Linear methods of reconstruction play an important role in medical electrical impedance tomography (EIT) and there is a wide variety of algorithms based on several assumptions. With the Graz consensus reconstruction algorithm for EIT (GREIT), a novel linear reconstruction algorithm as well as a standardized framework ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/6/1161
更新日期:2015-06-01 00:00:00
abstract::This study investigates the cerebral hemodynamic changes during a routine sleep-deprived video-electroencephalogram (SD-VEEG) in healthy children. Forty-two children with normal intelligence were examined. The children were 5-14 years of age, and their electroencephalograms (EEGs) were within the normal range. Each su...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/7/981
更新日期:2016-07-01 00:00:00
abstract::The holy grail of neuroimaging would be to have an imaging system, which could image neuronal electrical activity over milliseconds. One way to do this would be by imaging the impedance changes associated with ion channels opening in neuronal membranes in the brain during activity. In principle, we could measure this ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/1/040
更新日期:2004-02-01 00:00:00
abstract::Idiopathic normal pressure hydrocephalus (INPH) patients have a disturbance in the dynamics of the cerebrospinal fluid (CSF) system. The outflow conductance, C, of the CSF system has been suggested to be prognostic for positive outcome after treatment with a CSF shunt. All current methods for estimation of C have draw...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/11/003
更新日期:2007-11-01 00:00:00
abstract::Arterial pCO2 is known to influence cerebral autoregulation but its effect on the dynamic relationship between mean arterial blood pressure (ABP) and mean cerebral blood flow velocity (CBFV), obtained from spontaneous fluctuations in ABP, has not been established. In 16 normal subjects, ABP was measured non-invasively...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/20/3/304
更新日期:1999-08-01 00:00:00
abstract::Measurement of intracranial pressure (ICP) can be invaluable in the management of critically ill patients. Cerebrospinal fluid is produced by the choroid plexus in the brain ventricles (a set of communicating chambers), after which it circulates through the different ventricles and exits into the subarachnoid space ar...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aa7256
更新日期:2017-07-24 00:00:00
abstract::Gastro-oesophageal pH measurements are routinely carried out to quantify and determine if levels of acid reflux are responsible for symptoms. Although considered the 'gold standard', evidence suggests that pH measurements do not correlate well with the degree of oesophagitis seen during endoscopy. In this study the cu...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/24/4/006
更新日期:2003-11-01 00:00:00
abstract::Electrical impedance tomography (EIT) is very sensitive to deformations of the medium boundary shape. For lung imaging, breathing and changes in posture move the electrodes and change the chest shape, resulting in image artefacts. Several approaches have been proposed to improve the reconstructed images; most methods ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/6/S08
更新日期:2008-06-01 00:00:00
abstract::Skinfold anthropometry is a widely practiced technique often with little appreciation of its limitations. The large residual error appearing in any regressions of body density versus sums of skinfolds is primarily due to biological causes, in particular the non-constancy of the ratio of subcutaneous to total body fat....
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/19/3/008
更新日期:1998-08-01 00:00:00
abstract::Electrical impedance tomography (EIT) is a recent imaging technique based on electrical impedance, offering the possibility of measuring pulmonary perfusion. In the present study the influence of several pulmonary haemodynamical parameters on the EIT signal were investigated. First, the influence on the systolic wave ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/19/2/013
更新日期:1998-05-01 00:00:00
abstract::The measurement of the complex respiratory impedance at a high temporal resolution is described. The measurement of impedance is correlated with the breathing cycle using electrical transthoracic impedance. This allows the determination of the complex impedance at any fixed point in the respiratory cycle, which result...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/14/3/019
更新日期:1993-08-01 00:00:00
abstract::Cycling on an ergometer is one effective means of measuring cardiovascular function while applying stress on the heart. Bathing in a hot water bath applies a low stress to the heart. The electrocardiograms of a healthy adult male (aged 35 at the start of study) were recorded while taking a hot water bath with no elect...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/20/4/304
更新日期:1999-11-01 00:00:00
abstract::False alarm (FA) rates as high as 86% have been reported in intensive care unit monitors. High FA rates decrease quality of care by slowing staff response times while increasing patient burdens and stresses. In this study, we proposed a rule-based and multi-channel information fusion method for accurately classifying ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/8/1298
更新日期:2016-08-01 00:00:00
abstract::Multiple frequency bio-electrical impedance analysis (MFBIA) may be useful for monitoring fluid balance in newborn infants or to provide early prediction of the outcome following perinatal asphyxia. A reference range of data is needed for identification of babies with abnormal impedance values. This was a cross-sectio...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/11/010
更新日期:2006-11-01 00:00:00
abstract::The specific heat capacity of tissue is a critical parameter for thermal therapies that act over a long period of time. It is also critical for thermoacoustic signal generation. We present ex vivo measurements of specific heat capacity performed by a dual-pin probe with tight temperature control of the specimen. One 3...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/11/N02
更新日期:2011-11-01 00:00:00