Abstract:
:In this study, we designed and tested a new algorithm, which we call the 'restricted parabola', to identify the optimum atrioventricular (AV) delay in patients with biventricular pacemakers. This algorithm automatically restricts the hemodynamic data used for curve fitting to the parabolic zone in order to avoid inadvertently selecting an AV optimum that is too long.We used R, a programming language and software environment for statistical computing, to create an algorithm which applies multiple different cut-offs to partition curve fitting of a dataset into a parabolic and a plateau region and then selects the best cut-off using a least squares method. In 82 patients, AV delay was adjusted and beat-to-beat systolic blood pressure (SBP) was measured non-invasively using our multiple-repetition protocol. The novel algorithm was compared to fitting a parabola across the whole dataset to identify how many patients had a plateau region, and whether a higher hemodynamic response was achieved with one method.In 9/82 patients, the restricted parabola algorithm detected that the pattern was not parabolic at longer AV delays. For these patients, the optimal AV delay predicted by the restricted parabola algorithm increased SBP by 1.36 mmHg above that predicted by the conventional parabolic algorithm (95% confidence interval: 0.65 to 2.07 mmHg, p-value = 0.002).AV optima selected using our novel restricted parabola algorithm give a greater improvement in acute hemodynamics than fitting a parabola across all tested AV delays. Such an algorithm may assist the development of automated methods for biventricular pacemaker optimisation.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Dehbi HM,Jones S,Sohaib SM,Finegold JA,Siggers JH,Stegemann B,Whinnett ZI,Francis DPdoi
10.1088/0967-3334/36/9/1889subject
Has Abstractpub_date
2015-09-01 00:00:00pages
1889-900issue
9eissn
0967-3334issn
1361-6579journal_volume
36pub_type
杂志文章,随机对照试验abstract::Thermal sweating manikins are used to analyse the heat and mass transfer phenomena in the skin-clothing-environment system. However, the limiting factor of present thermal manikins is their inability to simulate adequately the human thermal behaviour, which has a significant effect on the clothing microenvironment. A ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/2/002
更新日期:2008-02-01 00:00:00
abstract::Temporal changes in the impedance spectra of bioelectrodes in contact with skin provide useful data for comparisons between differing electrode materials and skin preparation methods. Traditional impedance measuring systems employ swept frequency methods which will distort results in the impedance spectra of a sample ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/20/1/008
更新日期:1999-02-01 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
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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::There is considerable interest in unobtrusive and portable methods of monitoring sleepiness outside the laboratory setting. This study evaluates the usefulness of combined electrocardiogram (ECG) and photoplethysmogram (PPG) measurements for estimating psychomotor vigilance. The psychomotor vigilance test (PVT) was pe...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/8/001
更新日期:2008-08-01 00:00:00
abstract:OBJECTIVE:Plots of blood volume measurements over time (profiles) may identify euvolemia during fluid removal for acute heart failure. We assessed agreement between two noninvasive measurements of blood volume profiles during mechanical fluid removal, which exemplifies the interstitial fluid shifts that occur during di...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab21af
更新日期:2019-07-01 00:00:00
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journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
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abstract::Previous studies have proved that the baroreceptor reflex (baroreflex) control of heart rate can be used for stratification of post-infarction population and, in general, cardiovascular disease populations. Many methods have been proposed to estimate the so-called baroreflex sensitivity (BRS) expressed as ms mmhg-1. M...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/38/1/63
更新日期:2017-01-01 00:00:00
abstract::Using the cross-sectional images taken with the zoom-in micro-tomography technique, we measured trabecular thicknesses of femur bones in postmortem rats. Since the zoom-in micro-tomography technique is capable of high resolution imaging of a small local region inside a large subject, we were able to measure the trabec...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/5/008
更新日期:2005-10-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/2/014
更新日期:2004-04-01 00:00:00
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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::Near infrared spectroscopy (NIRS) is a widely employed method for assessment of regional cerebral oxygenation (RcStO2). RcStO2 values are expected to vary with changes in the relative amount of oxyhaemoglobin. The present experimental study aimed to assess the response of RcStO2 to controlled alterations of carotid bl...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/7/1439
更新日期:2014-07-01 00:00:00
abstract::The pre-ejection period (PEP) has recently been described as a potential parameter for monitoring cardiac preload. This study further investigated the influence of changes in intravascular volume status and the application of positive end-expiratory pressure (PEEP) on the pre-ejection period. In ten pigs, ECG, arteria...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/6/012
更新日期:2005-12-01 00:00:00
abstract::This paper introduces a new clinical distortion index able to measure the decrease in diagnostic content in compressed echocardiograms. It is calculated using cardiologists' answers to a clinical testbed composed of two types of tests: one blind and the other semi-blind. This index may be used to compare clinical perf...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/5/001
更新日期:2009-05-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aba07b
更新日期:2020-08-11 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/22/1/308
更新日期:2001-02-01 00:00:00
abstract::The goal of the present study was to develop and evaluate a new method for the prediction of unexplained syncope occurrences. Diagnosis of syncope is currently based on the reproduction of symptoms in combination with hypotension and bradycardia induced by a 45 min 60-70 degrees head-upright tilt test (HUTT). The main...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/28/2/007
更新日期:2007-02-01 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
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/9/1435
更新日期:2012-09-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/5/S16
更新日期:2006-05-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/4/010
更新日期:2004-08-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/10/2159
更新日期:2015-10-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab3493
更新日期:2019-11-04 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/10/2135
更新日期:2014-10-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/5/857
更新日期:2015-05-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/9/1624
更新日期:2016-09-01 00:00:00
abstract::This paper describes the design, construction, and testing of a multi-channel fetal electrocardiogram (fECG) signal generator based on LabVIEW. Special attention is paid to the fetal heart development in relation to the fetus' anatomy, physiology, and pathology. The non-invasive signal generator enables many parameter...
journal_title:Physiological measurement
pub_type: 杂志文章
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更新日期:2016-02-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
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更新日期:1993-11-01 00:00:00
abstract::The effects of mechanical stimulation on hemodynamics, such as due to mechanotransduction in vascular endothelial cells, have been widely discussed recently. We previously proposed a resonance model in which the arterial system is treated as a pressure-transmitting system, and suggested that the application of externa...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/2/004
更新日期:2006-02-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/6/007
更新日期:2004-12-01 00:00:00