The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform

Mathias Baumert - One of the best experts on this subject based on the ideXlab platform.

  • Beamforming-inspired Spatial Filtering Technique for Intracardiac Electrograms
    2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2019
    Co-Authors: Simanto Saha, Dominik Linz, Prashanthan Sanders, Mathias Baumert
    Abstract:

    Bipolar electrograms (EGM) are widely used to assess intracardiac electrical activity and to find the atrial fibrillation-related sources. However, the interpretation of bipolar EGM is not straightforward. Variables including bipolar Lead (Vector) orientation relative to the wave propagation dynamics significantly impact the EGM and EGM-derived measures, which are clinically used to select target sources for catheter ablation. In this study, left atrial unipolar EGM were recorded using a 4 × 4 grid of 16 unipolar electrodes. A set (node) of 4 unipolar EGM were used to construct possible 6 bipolar EGM to evaluate the measurement uncertainty within a particular node. A novel beamforming-inspired spatial filtering (BiSF) method is proposed to reduce the potential measurement uncertainty inevitable in bipolar EGM. A set of three bipolar Lead orientations that were constructed using a common unipolar electrode towards three different directions at 45°s, were added to form beamforming EGM. Finally, two beamforming EGM were intertwined to acquire BiSF EGM for a node. Results show greater signal power gain (at least around 10dB) for all BiSF EGM with better or similar signal-to-noise ratio as compared to their respective bipolar counterparts. In conclusion, reduced uncertainty in BiSF EGM improve the interpretation of EGM and EGM-derived measures used in clinical practice after further validation on a larger dataset.

  • EMBC - Beamforming-inspired Spatial Filtering Technique for Intracardiac Electrograms
    Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2019
    Co-Authors: Simanto Saha, Dominik Linz, Prashanthan Sanders, Mathias Baumert
    Abstract:

    Bipolar electrograms (EGM) are widely used to assess intracardiac electrical activity and to find the atrial fibrillation-related sources. However, the interpretation of bipolar EGM is not straightforward. Variables including bipolar Lead (Vector) orientation relative to the wave propagation dynamics significantly impact the EGM and EGM-derived measures, which are clinically used to select target sources for catheter ablation. In this study, left atrial unipolar EGM were recorded using a 4 × 4 grid of 16 unipolar electrodes. A set (node) of 4 unipolar EGM were used to construct possible 6 bipolar EGM to evaluate the measurement uncertainty within a particular node. A novel beamforming-inspired spatial filtering (BiSF) method is proposed to reduce the potential measurement uncertainty inevitable in bipolar EGM. A set of three bipolar Lead orientations that were constructed using a common unipolar electrode towards three different directions at 45°s, were added to form beamforming EGM. Finally, two beamforming EGM were intertwined to acquire BiSF EGM for a node. Results show greater signal power gain (at least around 10dB) for all BiSF EGM with better or similar signal-to-noise ratio as compared to their respective bipolar counterparts. In conclusion, reduced uncertainty in BiSF EGM improve the interpretation of EGM and EGM-derived measures used in clinical practice after further validation on a larger dataset.

Yoshio Okamoto - One of the best experts on this subject based on the ideXlab platform.

  • the absolute voltage and the Lead Vector of wilson s central terminal
    Japanese Heart Journal, 1996
    Co-Authors: Norio Miyamoto, Saburo Mashima, Yutaka Shimizu, Genyo Nishiyama, Yoshio Okamoto
    Abstract:

    The absolute potential value of Wilson's central terminal was calculated at 2 msec intervals during a cardiac cycle in 60 clinical cases. Starting from the body surface potential data at 128 thoracic locations, the effect of immersion of the body into an infinite conductor on the surface potential was calculated to obtain values with reference to zero potential at infinity. The conductivity of the outside medium was then made to approach zero.Comparison of the result with the original map showed nearly a constant shift of the potential, corresponding to the voltage of Wilson's terminal. In addition, the cardiac Vector was calculated as the first approximation of the cardiac electromotive force and the Lead Vector of Wilson's terminal was obtained in order that the scalar product of the cardiac Vector and the Lead Vector approximated the observed voltage of Wilson's terminal.The results indicate that the voltage of the Wilson electrode depended on the surface voltage with a peak value near the maximal QRS force in most of the cases. The peak voltage of Wilson's terminal was either positive or negative, and was 0.15mV in absolute value on average. Voltage variations of Wilson's terminal during a cardiac cycle were 0.20mV as an average of all cases. The voltage of Wilson's terminal also depended on the direction of the equivalent cardiac Vector. The Lead Vector of Wilson's terminal was found to be directed superiorly in most of the cases. The average magnitude of the Lead Vector of Wilson's terminal was 0.097Ω/cm, which corresponded to about 1/4 of that of Lead I.

  • On the potential of the wilson central terminal with respect to an ideal reference for unipolar electrocardiography
    Journal of Electrocardiology, 1995
    Co-Authors: Norio Miyamoto, Saburo Mashima, Yutaka Shimizu, Genyo Nishiyama, Yoshio Okamoto
    Abstract:

    Abstract Body surface potential mapping was performed in 60 clinical cases and an ideal 0 potential was calculated in each case at 2msec intervals, which corresponds to the potential at infinity. Maximal deviation of the Wilson terminal voltage the ideal potential was 0.14mv on the average. Time course of potential variations of the central terminal was in proportion to the measured surface potentials. The Lead Vector of Wilson terminal was determined for each case, with a method to make a minimal difference between calculate and observed Wilson terminal voltage. The Lead Vector was directed superiorly and posteriorly with the magnitude of 24% of that of Lead I on the average.

Simanto Saha - One of the best experts on this subject based on the ideXlab platform.

  • Beamforming-inspired Spatial Filtering Technique for Intracardiac Electrograms
    2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2019
    Co-Authors: Simanto Saha, Dominik Linz, Prashanthan Sanders, Mathias Baumert
    Abstract:

    Bipolar electrograms (EGM) are widely used to assess intracardiac electrical activity and to find the atrial fibrillation-related sources. However, the interpretation of bipolar EGM is not straightforward. Variables including bipolar Lead (Vector) orientation relative to the wave propagation dynamics significantly impact the EGM and EGM-derived measures, which are clinically used to select target sources for catheter ablation. In this study, left atrial unipolar EGM were recorded using a 4 × 4 grid of 16 unipolar electrodes. A set (node) of 4 unipolar EGM were used to construct possible 6 bipolar EGM to evaluate the measurement uncertainty within a particular node. A novel beamforming-inspired spatial filtering (BiSF) method is proposed to reduce the potential measurement uncertainty inevitable in bipolar EGM. A set of three bipolar Lead orientations that were constructed using a common unipolar electrode towards three different directions at 45°s, were added to form beamforming EGM. Finally, two beamforming EGM were intertwined to acquire BiSF EGM for a node. Results show greater signal power gain (at least around 10dB) for all BiSF EGM with better or similar signal-to-noise ratio as compared to their respective bipolar counterparts. In conclusion, reduced uncertainty in BiSF EGM improve the interpretation of EGM and EGM-derived measures used in clinical practice after further validation on a larger dataset.

  • EMBC - Beamforming-inspired Spatial Filtering Technique for Intracardiac Electrograms
    Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2019
    Co-Authors: Simanto Saha, Dominik Linz, Prashanthan Sanders, Mathias Baumert
    Abstract:

    Bipolar electrograms (EGM) are widely used to assess intracardiac electrical activity and to find the atrial fibrillation-related sources. However, the interpretation of bipolar EGM is not straightforward. Variables including bipolar Lead (Vector) orientation relative to the wave propagation dynamics significantly impact the EGM and EGM-derived measures, which are clinically used to select target sources for catheter ablation. In this study, left atrial unipolar EGM were recorded using a 4 × 4 grid of 16 unipolar electrodes. A set (node) of 4 unipolar EGM were used to construct possible 6 bipolar EGM to evaluate the measurement uncertainty within a particular node. A novel beamforming-inspired spatial filtering (BiSF) method is proposed to reduce the potential measurement uncertainty inevitable in bipolar EGM. A set of three bipolar Lead orientations that were constructed using a common unipolar electrode towards three different directions at 45°s, were added to form beamforming EGM. Finally, two beamforming EGM were intertwined to acquire BiSF EGM for a node. Results show greater signal power gain (at least around 10dB) for all BiSF EGM with better or similar signal-to-noise ratio as compared to their respective bipolar counterparts. In conclusion, reduced uncertainty in BiSF EGM improve the interpretation of EGM and EGM-derived measures used in clinical practice after further validation on a larger dataset.

Mohaddeseh Behjati - One of the best experts on this subject based on the ideXlab platform.

  • BIBE - Partial linear transformation of Vectorcardiogram to 12 Lead electrocardiogram signals
    2012 IEEE 12th International Conference on Bioinformatics & Bioengineering (BIBE), 2012
    Co-Authors: Alireza Mehridehnavi, Niloofar Salehpour, Hossein Rabbani, Mohaddeseh Behjati
    Abstract:

    The ability to transform orthogonal 3-Lead Vector-cardiogram (VCG) to 12-Lead Electrocardiogram (ECG) enables the use of fewer Leads for computer visualization, signal analysis and wireless transmission of signals. This can also improve mobility, albeit limited, to the patients. We presented a least square (LS)-based approach to transform 3-Lead Frank VCG to 12-Lead ECG signals and vice versa, using partial linear transformation. Also our partial linear transformation function would be compared with Dower and affine transformation functions. The VCG and ECG signals of 40 healthy persons are acquired in this study. The results show that for healthy subjects, our partial linear LS method that is maps 3-Lead VCG to12-Lead ECG more accurately than both Dower and affine transformations of the ECG recordings.

  • Partial linear transformation of Vectorcardiogram to 12 Lead electrocardiogram signals
    2012 IEEE 12th International Conference on Bioinformatics & Bioengineering (BIBE), 2012
    Co-Authors: Alireza Mehridehnavi, Niloofar Salehpour, Hossein Rabbani, Mohaddeseh Behjati
    Abstract:

    The ability to transform orthogonal 3-Lead Vector-cardiogram (VCG) to 12-Lead Electrocardiogram (ECG) enables the use of fewer Leads for computer visualization, signal analysis and wireless transmission of signals. This can also improve mobility, albeit limited, to the patients. We presented a least square (LS)-based approach to transform 3-Lead Frank VCG to 12-Lead ECG signals and vice versa, using partial linear transformation. Also our partial linear transformation function would be compared with Dower and affine transformation functions. The VCG and ECG signals of 40 healthy persons are acquired in this study. The results show that for healthy subjects, our partial linear LS method that is maps 3-Lead VCG to12-Lead ECG more accurately than both Dower and affine transformations of the ECG recordings.

Norio Miyamoto - One of the best experts on this subject based on the ideXlab platform.

  • the absolute voltage and the Lead Vector of wilson s central terminal
    Japanese Heart Journal, 1996
    Co-Authors: Norio Miyamoto, Saburo Mashima, Yutaka Shimizu, Genyo Nishiyama, Yoshio Okamoto
    Abstract:

    The absolute potential value of Wilson's central terminal was calculated at 2 msec intervals during a cardiac cycle in 60 clinical cases. Starting from the body surface potential data at 128 thoracic locations, the effect of immersion of the body into an infinite conductor on the surface potential was calculated to obtain values with reference to zero potential at infinity. The conductivity of the outside medium was then made to approach zero.Comparison of the result with the original map showed nearly a constant shift of the potential, corresponding to the voltage of Wilson's terminal. In addition, the cardiac Vector was calculated as the first approximation of the cardiac electromotive force and the Lead Vector of Wilson's terminal was obtained in order that the scalar product of the cardiac Vector and the Lead Vector approximated the observed voltage of Wilson's terminal.The results indicate that the voltage of the Wilson electrode depended on the surface voltage with a peak value near the maximal QRS force in most of the cases. The peak voltage of Wilson's terminal was either positive or negative, and was 0.15mV in absolute value on average. Voltage variations of Wilson's terminal during a cardiac cycle were 0.20mV as an average of all cases. The voltage of Wilson's terminal also depended on the direction of the equivalent cardiac Vector. The Lead Vector of Wilson's terminal was found to be directed superiorly in most of the cases. The average magnitude of the Lead Vector of Wilson's terminal was 0.097Ω/cm, which corresponded to about 1/4 of that of Lead I.

  • On the potential of the wilson central terminal with respect to an ideal reference for unipolar electrocardiography
    Journal of Electrocardiology, 1995
    Co-Authors: Norio Miyamoto, Saburo Mashima, Yutaka Shimizu, Genyo Nishiyama, Yoshio Okamoto
    Abstract:

    Abstract Body surface potential mapping was performed in 60 clinical cases and an ideal 0 potential was calculated in each case at 2msec intervals, which corresponds to the potential at infinity. Maximal deviation of the Wilson terminal voltage the ideal potential was 0.14mv on the average. Time course of potential variations of the central terminal was in proportion to the measured surface potentials. The Lead Vector of Wilson terminal was determined for each case, with a method to make a minimal difference between calculate and observed Wilson terminal voltage. The Lead Vector was directed superiorly and posteriorly with the magnitude of 24% of that of Lead I on the average.