Dariusz Janusek

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OBJECTIVE The aim of this study was to evaluate influence of noise, T-wave jitter and electrocardiographic (ECG) signal parameters on sensitivity of T-wave alternans (TWA) detection methods. METHODS Methods of the TWA detection were tested: correlation (CM), spectral (FFTM), spectral with coherent averaging (CFFTM), complex demodulation (CDM),(More)
BACKGROUND The effective screening of myocardial infarction (MI) patients threatened by ventricular tachycardia (VT) is an important issue in clinical practice, especially in the process of implantable cardioverter-defibrillator (ICD) therapy recommendation. This study proposes new parameters describing depolarization and repolarization inhomogeneity in(More)
The aim of the study was a selection of best ECG leads to get the significant T-wave alternans signal (TWA). The group of 16 patients with implantable cardioverter-defibrillator (ICD) was examined. The 64 lead ECG system was used. Three lead sets were analyzed: 64 BSPM lead set, orthogonal lead set (XYZ) and standard 12 lead set. Patients were divided into(More)
In the work presented here we propose a new approach for the TWA modelling and detection. For this aim, the ECG amplitude modulation and the baseline wander in the ST-T segment are approximated by a scaling factor applied to the T wave added to a constant. Thanks to this simplification , the proposed global model of each ST-T segment is constituted by the(More)
The conventional spectral method is indeed a typical confidence interval computation that use normalized Fourier transform frequencies F{f} at f = 0.5. In order to get a robust detector with respect to spikes due to single-frequency tone interference and to exploit the entire frequency band to reduce the variance we proposed new parameter called SMM(More)
In this work a simulation study of T-wave alternans is proposed in order to determine the ability of TWA detectors to quantify the performance characteristics in terms of amplitude estimation accuracy. ECG signals were simulated by repeating a single beat, and by adding four types of noise each at two different levels of power. TWA episodes with different(More)
Inaccurate electrode placement and differences in inter-individual human anatomies can lead to misinterpretation of ECG examination. The aim of the study was to investigate the effect of precordial electrodes displacement on morphology of the ECG signal in a group of 60 patients with diagnosed cardiac disease. Shapes of ECG signals recorded from precordial(More)
The aim of the study was to determine optimal measurement conditions for assessment of brain perfusion with the use of optical contrast agent and time-resolved diffuse reflectometry in the near-infrared wavelength range. The source-detector separation at which the distribution of time of flights (DTOF) of photons provided useful information on the inflow of(More)
The influence of T-wave alternans (TWA) on vectocardiographic parameters has been presented. Alternations in the length and the angle of T-wave loop vector have been found between odd and even beats in electrocardiograms with detectable T-wave alternans. The study shows the significance of changes of T-wave loop vector length and angle in the process of(More)
Vectorcardiographic representation of T-wave alternans (TWA) has been presented in new coordinate system created by means of singular value decomposition where the first axis was in T-loop direction and other axes were perpendicular. Projection of T-loop vector on the plane perpendicular to the first axis was analyzed. The study shows that in case of(More)