Modular measuring system for assessment of the thyroid gland functional state

Distributed modular system BioLab for biophysical examinations enabling assessment of the thyroid gland functional state is presented in the paper. The BioLab system is based on a standard notebook or desktop PC connected to an Ethernet-based network of two smart sensors. These sensors are programmed and controlled from PC and enable measurement of selected biosignals of the human cardiovascular and neuromuscular system that are influenced by the production of thyroid gland hormones. Recorded biosignals are processed in a PC and peripheral indicators characterizing thyroid gland functional state are evaluated

Modeling as a Tool for Understanding of Changes in ECG Signals

Abstract. An updated program for modeling simplified heart geometry and simulation of action potentials propagation is presented

Use of body surface potential maps for model-based assessment of local pathological changes in the heart

Abstract. High resolution body surface potential maps and an equivalent current dipole model of the cardiac generator were used to assess the heart state in two abnormal conditions: WPW syndrome with single accessory pathway and local ventricular ischemia. Results of a simulation study and experimental verification of the method for both cardiologic abnormalities are presented. Single accessory pathway in WPW syndrome was simulated as initial ventricular activation at the atrio-ventricular ring. Using a current dipole model of the cardiac generator, the locus of arrhythmogenic tissue was assessed with a mean error of 11 mm. Experimental localization of the accessory pathway in a WPW patient was in good agreement with the invasively obtained site. Local repolarization changes were simulated as shortening of the myocytes action potentials in three regions typical for stenosis of main coronary arteries. Using surface QRST integral maps and dipolar source model, small subendocardial and subepicardial lesions of myocardium were inversely located with a mean error of 9 mm and larger transmural lesions with a considerable mean error of 17 mm. Extent and prevalence of subepicardial or subendocardial type of the lesion were reflected in the dipole moment and orientation. In experimental verification of the method, in 7 of 8 patients that underwent PCI of a single vessel, estimated equivalent current dipole position matched well the treated vessel. The results suggest that diagnostic interpretation of body surface potential maps based on dipolar source model could be a useful tool to assess local pathological changes in the heart