Physiological research / Academia Scientiarum Bohemoslovaca, Jan 21, 2013
Motion artefact (MA) in voltage-sensitive fluorescent signals causes significant debasement of ac... more Motion artefact (MA) in voltage-sensitive fluorescent signals causes significant debasement of action potential. During ischemia and reperfusion in isolated rabbit heart, this artefact develops in a manner which may be described by the time of its onset, level, and shape. The MA during ischemia: (a) may become substantial with approximately two minutes delay after establishing global ischemia; (b) may be almost twice as high as the physiological action potential and decreases both with time and repetition of ischemia; (c) the MA shape is unpredictable and depends on individual rabbit.
ABSTRACT Heart rate variability (HRV) in in-vivo and isolated hearts was evaluated by complex cor... more ABSTRACT Heart rate variability (HRV) in in-vivo and isolated hearts was evaluated by complex correlation measure (CCM) and Poincaré descriptors SD1 and SD2. CCM quantifies temporal aspect of Poincaré plot; SD1 and SD2 quantify final shape of Poincaré diagram only.
Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies - ISABEL '11, 2011
There are many different methods for evaluation of alertness level of a person. The commonly used... more There are many different methods for evaluation of alertness level of a person. The commonly used questionnaires and some physiological test such as flicker-fusion (FF) test are not objective. Other objective methods based on the analysis of biological signals can be used for validation of these tests. The present study is focused on analysis of spectral features of EEG measured
ABSTRACT Optical signals reflect electrical changes in the heart; however, the presence of motion... more ABSTRACT Optical signals reflect electrical changes in the heart; however, the presence of motion artifact (MA) complicates the evaluation. Possibility of MA suppression by independent component analysis (ICA) method is presented in this article with an analysis of ICA efficiency and its limitations. Suppression of MA by ICA method was compared with results obtained by state-of-the-art signal processing method, the ratio method. Based on this comparison, the ICA was found as highly precise and useful method for motion artifact removal. ICA seems to be a promising tool for analysis of optical signals recorded from the heart surface.
Heart rate variability of seven isolated and five in-vivo rabbit hearts was compared. Heart rate ... more Heart rate variability of seven isolated and five in-vivo rabbit hearts was compared. Heart rate of isolated hearts is lower and RR-intervals longer than those of in-vivo hearts. Characteristic peaks in characteristic frequency bands are different and powers of these bands are almost twice higher in in-vivo hearts than in isolated ones. LF/HF ratio is more than five-times higher in
Physiological research / Academia Scientiarum Bohemoslovaca, Jan 21, 2013
Motion artefact (MA) in voltage-sensitive fluorescent signals causes significant debasement of ac... more Motion artefact (MA) in voltage-sensitive fluorescent signals causes significant debasement of action potential. During ischemia and reperfusion in isolated rabbit heart, this artefact develops in a manner which may be described by the time of its onset, level, and shape. The MA during ischemia: (a) may become substantial with approximately two minutes delay after establishing global ischemia; (b) may be almost twice as high as the physiological action potential and decreases both with time and repetition of ischemia; (c) the MA shape is unpredictable and depends on individual rabbit.
ABSTRACT Heart rate variability (HRV) in in-vivo and isolated hearts was evaluated by complex cor... more ABSTRACT Heart rate variability (HRV) in in-vivo and isolated hearts was evaluated by complex correlation measure (CCM) and Poincaré descriptors SD1 and SD2. CCM quantifies temporal aspect of Poincaré plot; SD1 and SD2 quantify final shape of Poincaré diagram only.
Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies - ISABEL '11, 2011
There are many different methods for evaluation of alertness level of a person. The commonly used... more There are many different methods for evaluation of alertness level of a person. The commonly used questionnaires and some physiological test such as flicker-fusion (FF) test are not objective. Other objective methods based on the analysis of biological signals can be used for validation of these tests. The present study is focused on analysis of spectral features of EEG measured
ABSTRACT Optical signals reflect electrical changes in the heart; however, the presence of motion... more ABSTRACT Optical signals reflect electrical changes in the heart; however, the presence of motion artifact (MA) complicates the evaluation. Possibility of MA suppression by independent component analysis (ICA) method is presented in this article with an analysis of ICA efficiency and its limitations. Suppression of MA by ICA method was compared with results obtained by state-of-the-art signal processing method, the ratio method. Based on this comparison, the ICA was found as highly precise and useful method for motion artifact removal. ICA seems to be a promising tool for analysis of optical signals recorded from the heart surface.
Heart rate variability of seven isolated and five in-vivo rabbit hearts was compared. Heart rate ... more Heart rate variability of seven isolated and five in-vivo rabbit hearts was compared. Heart rate of isolated hearts is lower and RR-intervals longer than those of in-vivo hearts. Characteristic peaks in characteristic frequency bands are different and powers of these bands are almost twice higher in in-vivo hearts than in isolated ones. LF/HF ratio is more than five-times higher in
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