keyword
MENU ▼
Read by QxMD icon Read
search

Impedance cardiography

keyword
https://www.readbyqxmd.com/read/29150800/beat-to-beat-estimation-of-stroke-volume-using-impedance-cardiography-and-artificial-neural-network
#1
S M M Naidu, Prem C Pandey, Uttam R Bagal, Suhas P Hardas
Impedance cardiography is a low-cost noninvasive technique, based on monitoring of the thoracic impedance, for estimation of stroke volume (SV). Impedance cardiogram (ICG) is the negative of the first derivative of the impedance signal. A technique for beat-to-beat SV estimation using impedance cardiography and artificial neural network (ANN) is proposed. A three-layer feed-forward ANN with error back-propagation algorithm is optimized by examining the effects of number of neurons in the hidden layer, activation function, training algorithm, and set of input parameters...
November 18, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/29131882/time-course-response-of-the-heart-and-circulatory-system-to-active-postural-changes
#2
Jo P Pauls, Llion Roberts, Tom Burgess, John/F Fraser, Shaun/D Gregory, Geoff Tansley
Rotary blood pumps (RBPs) used for mechanical circulatory support of heart failure patients cannot passively change pump flow sufficiently in response to frequent variations in preload induced by active postural changes. A physiological control system that mimics the response of the healthy heart is needed to adjust pump flow according to patient demand. Thus, baseline data is required on how the healthy heart (i.e. heart rate (HR) and cardiac output (CO)) and circulatory system (i.e. systemic vascular resistance (SVR)) respond...
November 13, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/29123459/wearable-sensing-of-cardiac-timing-intervals-from-cardiogenic-limb-vibration-signals
#3
Andrew D Wiens, Ann Johnson, Omer T Inan
In this paper we describe a new method to measure aortic valve opening (AVO) and closing (AVC) from cardiogenic limb vibrations (i.e., wearable ballistocardiogram [BCG] signals). AVO and AVC were detected for each heartbeat with accelerometers on the upper arm (A), wrist (W), and knee (K) of 22 subjects following isometric exercise. Exercise-induced changes were recorded with impedance cardiography. The method, Filter BCG, detects peaks in distal vibrations after filtering with individually-tuned bandpass filters...
March 1, 2017: IEEE Sensors Journal
https://www.readbyqxmd.com/read/29102503/maternal-hemodynamics-a-method-to-classify-hypertensive-disorders-of-pregnancy
#4
Enrico Ferrazzi, Tamara Stampalija, Lorenzo Monasta, Daniela Di Martino, Sharona Vonck, Wilfried Gyselaers
BACKGROUND: The classification of hypertensive disorders of pregnancy (HDP) is based on the time at the onset of hypertension, proteinuria, and other associated complications. Maternal hemodynamic interrogation in HDP considers not only the peripheral blood pressure but also the entire cardiovascular system, and it might help to classify the different clinical phenotypes of this syndrome. OBJECTIVES: This study aimed to examine cardiovascular parameters in a cohort of patients affected by HDP according to the clinical phenotypes that prioritize fetoplacental characteristics and not the time at onset of HDP...
November 1, 2017: American Journal of Obstetrics and Gynecology
https://www.readbyqxmd.com/read/29073767/arterial-stiffness-is-associated-with-qtc-interval-prolongation-in-patients-with-heart-failure
#5
Salah Al-Zaiti, Samir Saba, Rodolfo Pike, Jennifer Williams, Fadi Khraim
BACKGROUND: A prolonged corrected QT (QTc) interval is a known risk factor for adverse cardiac events. Understanding the determinants and physiologic correlates of QTc is necessary for selecting proper strategies to reduce the risk of adverse events in high-risk patients. We sought to evaluate the role of arterial stiffness in heart failure as a determinant of QTc prolongation. METHOD: This was an observational study that recruited ambulatory heart failure patients (New York Heart Association Classes I-II) from an outpatient heart failure clinic...
January 1, 2017: Biological Research for Nursing
https://www.readbyqxmd.com/read/29051338/the-occurrence-of-cardiac-output-decrease-via-stroke-volume-is-more-pronounced-in-women-than-in-men-during-prolonged-dry-static-apnoea
#6
Sara Magnani, Gabriele Mulliri, Gianmarco Sainas, Giovanna Ghiani, Virginia Pinna, Irene Sanna, Antonio Crisafulli, Filippo Tocco
Little is known on gender differences in autonomic cardiovascular regulation of diving response (DR) and the few available studies into these differences were conducted on subjects with limited or no diving experience. We examined gender influence on hemodynamics during dry-static apnoea (SA) in 8 male and 8 female elite divers matched for their breath-hold (BH) ability. Hemodynamics was assessed by means of simultaneous echocardiography and impedance cardiography measurements and arterial pressure and oxygen saturation (SaO2) were also collected...
October 19, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28983659/cardiac-and-peripheral-vasomotor-autonomic-functions-in-late-onset-transthyretin-val30met-familial-amyloid-polyneuropathy
#7
Haruki Koike, Tomohiko Nakamura, Atsushi Hashizume, Ryoji Nishi, Shohei Ikeda, Yuichi Kawagashira, Masahiro Iijima, Masahisa Katsuno, Gen Sobue
The objective of this study was to systematically investigate cardiac and peripheral vasomotor autonomic functions in late-onset transthyretin Val30Met familial amyloid polyneuropathy (FAP ATTR Val30Met) patients from non-endemic areas. The coefficient of variation of R-R intervals (CVR-R), responses to the Valsalva manoeuvre, head-up tilt test with impedance cardiography, noradrenaline infusion test, and (123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy were assessed in eight patients. Although only four patients manifested orthostatic hypotension during the head-up tilt test, CVR-R, responses to the Valsalva manoeuvre, and myocardial MIBG uptake indicated a higher prevalence of cardiac sympathetic and parasympathetic dysfunction...
November 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28948370/reliability-of-peak-exercise-stroke-volume-assessment-by-impedance-cardiography-in-patients-with-residual-right-outflow-tract-lesions-after-congenital-heart-disease-repair
#8
Antoine Legendre, D Bonnet, L Bosquet
Global ventricular response to exercise may be useful in follow-up of patients with residual right outflow tract lesions after congenital heart disease repair. In this context, impedance cardiography is considered accurate for stroke volume (SV) measurement during exercise testing, however, to date, only partial assessment of its reliability has been reported. We retrospectively evaluated relative and absolute reliability of peak SV by impedance cardiography during exercise using intraclass correlation (ICC) and standard error of measurement (SEM) in this population...
September 25, 2017: Pediatric Cardiology
https://www.readbyqxmd.com/read/28939932/prognostic-value-of-selected-echocardiographic-impedance-cardiographic-and-hemodynamic-parameters-determined-during-right-heart-catheterization-in-patients-qualified-for-heart-transplantation
#9
Wojciech Gilewski, Jarosław Pietrzak, Joanna Banach, Robert Bujak, Jan Błażejewski, Danuta Karasek, Łukasz Wołowiec, Władysław Sinkiewicz
The aim of the study was to verify prognostic value of selected echocardiographic (UKG), impedance cardiography (ICG), and right heart catheterization (RHC) parameters in systolic heart failure (HF). UKG, ICG, and RHC were performed in 46 patients with chronic HF with ejection fraction <35%. During a 1-year follow-up, composite endpoint (death or hospitalization due to HF exacerbation) was achieved by 23 (50.0%) patients. Analysis of receiver operating characteristic (ROC) curves identified UKG parameters: inferior vena cava diameter on inspiration (IVCinsp) >13 mm [area under curve (AUC), 0...
September 22, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/28937981/cognitive-function-in-patients-with-stable-coronary-heart-disease-related-cerebrovascular-and-cardiovascular-responses
#10
Mathieu Gayda, Vincent Gremeaux, Louis Bherer, Martin Juneau, Joffrey Drigny, Olivier Dupuy, Gabriel Lapierre, Véronique Labelle, Annik Fortier, Anil Nigam
Chronic exercise has been shown to prevent or slow age-related decline in cognitive functions in otherwise healthy, asymptomatic individuals. We sought to assess cognitive function in a stable coronary heart disease (CHD) sample and its relationship to cerebral oxygenation-perfusion, cardiac hemodynamic responses, and [Formula: see text] peak compared to age-matched and young healthy control subjects. Twenty-two young healthy controls (YHC), 20 age-matched old healthy controls (OHC) and 25 patients with stable CHD were recruited...
2017: PloS One
https://www.readbyqxmd.com/read/28937241/preejection-period-as-a-sympathetic-activity-index-a-role-of-confounding-factors
#11
J Krohova, B Czippelova, Z Turianikova, Z Lazarova, I Tonhajzerova, M Javorka
In previous studies, one of the systolic time intervals - preejection period (PEP) - was used as an index of sympathetic activity reflecting the cardiac contractility. However, PEP could be also influenced by several other cardiovascular variables including preload, afterload and diastolic blood pressure (DBP). The aim of this study was to assess the behavior of the PEP together with other potentially confounding cardiovascular system characteristics in healthy humans during mental and orthostatic stress (head-up tilt test - HUT)...
September 22, 2017: Physiological Research
https://www.readbyqxmd.com/read/28902662/circadian-hemodynamics-in-men-and-women-with-high-blood-pressure-dipper-vs-nondipper-and-racial-differences
#12
Andrew Sherwood, LaBarron K Hill, James A Blumenthal, Alan L Hinderliter
OBJECTIVE: The 'nondipping' pattern of circadian blood pressure (BP) variation is an established independent predictor of adverse cardiovascular outcomes. Although this phenomenon has been widely studied, its underlying circadian hemodynamics of cardiac output and systemic vascular resistance (SVR) have not been well characterized. We evaluated the hypothesis that BP nondipping would be associated with a blunted night-time reduction in SVR in a biracial sample of 140 (63 African-American and 77 white) men and women with elevated clinic BP (130-159/85-99 mmHg)...
September 11, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28895755/hemodynamic-characterization-of-hypertensive-patients-with-an-exaggerated-orthostatic-blood-pressure-variation
#13
Jessica Barochiner, Lucas S Aparicio, José Alfie, Marcelo A Rada, Margarita S Morales, Carlos R Galarza, Paula E Cuffaro, Marcos J Marín, Rocío Martínez, Gabriel D Waisman
Exaggerated orthostatic blood pressure variation (EOV) is a poorly understood phenomenon related to high cardiovascular risk. We aimed to determine whether hypertensive patients with EOV have a distinct hemodynamic pattern, assessed through impedance cardiography. METHODS: In treated hypertensive patients, we measured the cardiac index (CI), systemic vascular resistance index (SVRI), blood pressure (BP), and heart rate (HR) in the supine and standing (after 3 minutes) positions, defining three groups according to BP variation: 1) Normal orthostatic BP variation (NOV): standing systolic BP (stSBP)-supine systolic BP (suSBP) between -20 and 20 mmHg and standing diastolic BP (stDBP)-supine diastolic BP (suDBP) between -10 and 10 mmHg; 2) orthostatic hypotension (OHypo): stSBP-suSBP≤-20 or stDBP-suDBP≤-10 mmHg; 3) orthostatic hypertension (OHyper): stSBP-suSBP≥20 or stDBP-suDBP≥10 mmHg...
September 12, 2017: Clinical and Experimental Hypertension: CHE
https://www.readbyqxmd.com/read/28887501/voluntary-liquorice-ingestion-increases-blood-pressure-via-increased-volume-load-elevated-peripheral-arterial-resistance-and-decreased-aortic-compliance
#14
Elina J Hautaniemi, Anna M Tahvanainen, Jenni K Koskela, Antti J Tikkakoski, Mika Kähönen, Marko Uitto, Kalle Sipilä, Onni Niemelä, Jukka Mustonen, Ilkka H Pörsti
We investigated the haemodynamic effects of two-week liquorice exposure (glycyrrhizin dose 290-370 mg/day) in 22 healthy volunteers during orthostatic challenge. Haemodynamics were recorded during passive 10-minute head-up tilt using radial pulse wave analysis, whole-body impedance cardiography, and spectral analysis of heart rate variability. Thirty age-matched healthy subjects served as controls. Liquorice ingestion elevated radial systolic (p < 0.001) and diastolic (p = 0.018) blood pressure and systemic vascular resistance (p = 0...
September 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28864438/measuring-stroke-volume-impedance-cardiography-vs-phase-contrast-magnetic-resonance-imaging
#15
Matthew Borzage, Kimia Heidari, Thomas Chavez, Istvan Seri, John C Wood, Stefan Blüml
BACKGROUND: Determination of cardiac output requires measurement of both heart rate and stroke volume. Techniques for measuring heart rate are widespread, and 1 technique for bedside monitoring of stroke volume is electrical impedance cardiography. OBJECTIVES: To determine the accuracy and precision of stroke volume measured via impedance cardiography and whether the technique can be used to detect trends. METHODS: Eleven healthy research participants (22-52 years old) were examined with simultaneous impedance cardiography and phase-contrast magnetic resonance imaging at rest and during exercise...
September 2017: American Journal of Critical Care: An Official Publication, American Association of Critical-Care Nurses
https://www.readbyqxmd.com/read/28841341/systemic-vascular-resistance-and-endogenous-inhibitors-of-nitric-oxide-synthesis-in-early-compared-to-late-onset-preeclampsia-preliminary-findings
#16
Miha Lucovnik, Helmut Karl Lackner, Ilona Papousek, Karin Schmid-Zalaudek, Guenter Schulter, Andreas Roessler, Manfred Georg Moertl
OBJECTIVE: To examine systemic vascular resistance index (SVRI), asymmetric (ADMA) and symmetric dimethylarginine (SDMA) levels in preeclampsia at different gestations. METHODS: Twenty-four preeclamptic patients (14 at ≥ 34 weeks') and 72 matched healthy controls were included. SVRI was calculated from impedance cardiography measurements. ADMA and SDMA levels were determined using enzyme-linked immunosorbent assay. RESULTS: SVRI and SDMA were higher in preeclampsia overall, in early onset and late onset compared to controls...
August 2017: Hypertension in Pregnancy
https://www.readbyqxmd.com/read/28805112/casting-doubt-on-the-value-of-assessing-the-cardiac-index-in-pregnancy
#17
Maya Ram, Anat Lavie, Shaul Lev, Yair Blecher, Uri Amikam, Yael Shulman, Tomer Avnon, Eran Weiner, Ariel Many
OBJECTIVES: The objective of this study is to assess the reliability of the cardiac index (CI) in healthy pregnant women at term by investigating the correlation between the cardiac output (CO) and the body surface area (BSA) using a novel non-invasive cardiography technique (NICaS™). METHODS: Sixty-one healthy, normotensive women with a singleton pregnancy at term (≥37 gestational weeks) participated in this prospective observational study between 1/2015 and 6/2015 L...
August 13, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28795669/-evaluation-of-volume-overload-in-critical-patients-by-monitoring-change-of-cardiac-output-under-bed-head-raising-combined-with-passive-leg-raising
#18
Long Zhang, Luhao Wang, Weixiong Luo, Meihua Mei, Youjuan Chen, Bin Ouyang
OBJECTIVE: To investigate whether the change of cardiac output (CO) with bed head raising (BHR) combined with passive leg raising (PLR) can be used to assess volume overload in critical patients. METHODS: A prospective observational diagnostic trial was designed. The patients who underwent fluid resuscitation 6 hours or more, and admitted to intensive care unit (ICU) of Meizhou People's Hospital in Guangdong Province from January to December in 2016 were enrolled...
August 2017: Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
https://www.readbyqxmd.com/read/28769819/substantial-inter-subject-variability-in-blood-pressure-responses-to-glucose-in-a-healthy-non-obese-population
#19
Cathriona R Monnard, Benoît Fellay, Isabelle Scerri, Erik K Grasser
Aim: A large inter-subject variability in the blood pressure (BP) response to glucose drinks has been reported. However, the underlying factors remain elusive and we hypothesized that accompanying changes in glucose metabolism affect these BP responses. Methods: Cardiovascular and glycemic changes in response to a standard 75 g oral-glucose-tolerance-test were investigated in 30 healthy, non-obese males. Continuous cardiovascular monitoring, including beat-to-beat BP, electrocardiographically deduced heart rate and impedance cardiography, was performed during a 30 min baseline and continued up to 120 min after glucose ingestion...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28757153/hemodynamic-determinants-of-the-biological-variation-of-nt-probnp-in-patients-with-stable-systolic-chronic-heart-failure
#20
Tobias Täger, Ann-Kathrin Wiedergruen, Hanna Fröhlich, Rita Cebola, Anna Corletto, Andrea Horsch, Georg Hess, Karen Slottje, Dietmar Zdunek, Hugo A Katus, Frank H Wians, Lutz Frankenstein
BACKGROUND: Biological variation of amino-terminal probrain natriuretic peptide (NT-proBNP) in chronic heart failure (CHF) may affect blood levels and risk stratification. The sources of NT-proBNP variation are unknown. METHODS AND RESULTS: We performed NT-proBNP measurements, clinical and hemodynamic assessment in 50 patients with HFrEF who met criteria for clinical stability at 2 time intervals. Hemodynamic variables were measured using inert gas rebreathing and impedance cardiography...
July 27, 2017: Journal of Cardiac Failure
keyword
keyword
68208
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"