I. Viscor

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We use our bioimpedance monitor to test ability of impedance cardiography method to measure the change of stroke volume during Mueller maneuver in patients with mitral regurgitation. Although the results are reproducible for each subject, the stroke volume rises during maneuver in substantial part of subjects. This contradicts previous findings from other(More)
Elevated arterial stiffness is a marker of vascular aging and is connected with increased mortality. Noninvasive measurement of arterial stiffness is based on the measurement of pulse wave velocity (PWV), where PWV correlates with arterial stiffness. PWV depends on blood pressure and other physiological conditions. The aim of our study was to measure and(More)
Increased arterial stiffness is connected with vascular aging and cardiovascular diseases. Arterial stiffness correlates to Pulse Wave Velocity (PWV) which can be measured by the bioimpedance method. The bioimpedance plethysmographic signal was measured by a non-invasive Multichannel Bioimpedance Monitor and the PWV in the thigh and calf was calculated.(More)
This study introduces a method for detection of ventricular depolarization activity and the transfer of this activity into an audible stereo audio signal. Heart potentials are measured by an ultra-high-frequency high-dynamic-range electrocardiograph (UHF-ECG) with a 25-kHz sampling rate. Averaged and prolonged UHF amplitude envelopes of V1-3 and V4-6 leads(More)
The study presents a method for quantification of the respiratory effect on the thoracic impedance signal. We used measurements with 18 simultaneously scanning impedance signal locations. Elimination of breathing is based on the assumption that the neck and limb impedance signal measures only the variability in systemic blood pressure and is not affected by(More)
We introduce our conception of a two-channel bioimpedance monitor for the impedance cardiography. We are describing the design of a homemade device which is based on a direct digital synthesizer and a digital down converter. This solution enables us to obtain a high-quality bioimpedance signal, which can be used for computing the cardiac output beat per(More)
The dynamic range of broadband digital system is mostly limited by harmonics and spurious arising from ADC nonlinearity. The nonlinearity may be described in several ways. The distinction between static and dynamic contributions has strong theoretical motivations but it is difficult to independently measure these contributions. A more practical approach is(More)
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