Biomagnetic Validation to Skin Level for Blood Pressure Curves and Venous (original) (raw)
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International Congress Series, 2007
An alternative to assess arterial pulse wave (APW) is proposed. The blood pressure changes measurement at the jugular anatomical region, using a differential magnetic gradiometer was performed through sensing the slight mechanical pulsations of the skin without applied manual pressure. A well defined waveform, resembling general features of the electrocardiogram QRS complex, is obtained. The potential application of a non-expensive clinical monitoring of the APW measured at the jugular region and at other point of interest could be the precise pulse time differences to performed arterial pulse wave velocity (APWV) measurements.
Registration of Intravascular Pressure Curves: Magneto-Mechanical Evaluation
2008
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Physiological Measurement, 2012
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Radiation and Environmental Biophysics, 1996
This investigation studied the effects of 50-Hz electric and magnetic fields on the pulse rate and blood pressure in humans. Electrocardiograms (ECG) and the blood pressure of 41 male volunteers were recorded using ambulatory methods. Twenty-six subjects were measured in and outside real fields and 15 subjects in and outside 'sham' fields. The results of the ECG recordings have been presented earlier. This article deals with the analysis of the blood pressure measurements. Measurement took 3 hrs. First, the subjects spent 1 h outside the fields, then 1 h in real or 'sham' fields, followed by 1 h outside the fields. The electric field strength varied from 3.5 to 4.3 kV/m and the magnetic flux density from 1.4 to 6.6 µT. When analysing the blood pressure, which was measured with a noninvasive cuff method, it could not be shown that the fields (<4.3 kV/m and <6.6 µT) affected diastolic or systolic blood pressure.
Resonancia magnética en cardiología
Revista Latinoamericana De Hipertension, 2017
Nuclear magnetic resonance principle based on the use of radio frequency waves and magnetic fields is the basis of the pro - cess of generating thr...
Objective: To compare changes in heart rate (HR) and blood pressure (BP) associated with short-term exposure to static magnetic elds (SMFs) of positive versus negative polarity. Design: A double-blind, randomized controlled trial using a time series design. Setting: Physical therapy laboratory in a university setting. Subjects: Seventy-ve adults with a mean age of 30.6 years were assigned to one of three treatment groups. No subjects had any symptoms of cardiovascular disease or cardiac irregularity. Interventions: Fifteen-minute exposure to an SMF by lying on a mattress pad containing magnets of positive polarity, negative polarity, or none (placebo). Main outcome measures: HR and BP were monitored prior to exposure, at 1-minute, 5-minute, 10-minute and 15-minute intervals following exposure, and again 5 minutes after exposure. Results: Subjects in all groups demonstrated slight decreases in HR and BP, but none of these changes were associated with the intervention (p = 0.170). Conclusions: Short-term exposure to an SMF of either positive or negative polarity does not appear to cause any clinically meaningful changes in HR or BP among asymptomatic subjects. This nding supports the safe use of unipolar SMFs that contain low-intensity magnets (<1000 gauss) relative to the cardiovascular system.
Measuring blood flow velocity with a magnetic label
Journal of Physics: Conference Series, 2019
The article describes the method of measuring blood flow velocity by a non-invasive method of magnetizing blood with a magnetic pulse and detecting a magnetized substance using a magnetoelectric magnetic field sensor. The influence of the magnetic field on the parameters of blood and blood flow is considered. The methods of measuring blood flow velocity are considered, the distinguishing features of each method are given. The use of a magnetoelectric composite structure of bidomain lithium niobate\nickel\metglas is proposed as a sensitive element for detecting blood flow velocity.
Bioimpedância transtorácica comparada à ressonância magnética na avaliação do débito cardíaco
Arquivos Brasileiros de Cardiologia, 2012
Background: Cardiac magnetic resonance imaging is considered the gold-standard method for the calculation of cardiac volumes. Transthoracic impedance cardiography assesses the cardiac output. No studies validating this measurement, in comparison to that obtained by magnetic resonance imaging, are available. Objective:To evaluate the performance of transthoracic impedance cardiography in the calculation of the cardiac output, cardiac index and stroke volume using magnetic resonance imaging as the gold-standard. Methods:31 patients with a mean age of 56.7 ± 18 years were assessed; of these, 18 (58%) were males. Patients whose indication for magnetic resonance imaging required pharmacologic stress test were excluded. Correlation between methods was assessed using the Pearson's coefficient, and dispersion of absolute differences in relation to the mean was demonstrated using the Bland-Altman's method. Agreement between methods was analyzed using the intraclass correlation coefficient. Results: The mean cardiac output by transthoracic impedance cardiography and by magnetic resonance imaging was 5.16 ± 0.9 and 5.13 ± 0.9 L/min, respectively. Good agreement between methods was observed for cardiac output (r = 0.79; p = 0.0001), cardiac index (r = 0.74; p = 0.0001) and stroke volume (r = 0.88; p = 0.0001). The analysis by the Bland-Altman plot showed low dispersion of differences in relation to the mean, with a low amplitude of agreement intervals. Good agreement between the two methods was observed when analyzed by the intraclass correlation coefficient, with coefficients for cardiac output, cardiac index and stroke volume of 0.78, 0.73 and 0.88, respectively (p < 0.0001 for all comparisons). Conclusion: Transthoracic impedance cardiography proved accurate in the calculation of the cardiac output in comparison to cardiac magnetic resonance imaging.