Vessela Tz. Krasteva

Learn More
The prompt and adequate detection of abnormal cardiac conditions by computer-assisted long-term monitoring systems depends greatly on the reliability of the implemented ECG automatic analysis technique, which has to discriminate between different types of heartbeats. In this paper, we present a comparative study of the heartbeat classification abilities of(More)
BACKGROUND Peripheral nerves are situated in a highly non-homogeneous environment, including muscles, bones, blood vessels, etc. Time-varying magnetic field stimulation of the median and ulnar nerves in the carpal region is studied, with special consideration of the influence of non-homogeneities. METHODS A detailed three-dimensional finite element model(More)
BACKGROUND Transthoracic defibrillation is the most common life-saving technique for the restoration of the heart rhythm of cardiac arrest victims. The procedure requires adequate application of large electrodes on the patient chest, to ensure low-resistance electrical contact. The current density distribution under the electrodes is non-uniform, leading to(More)
BACKGROUND Magnetic stimulation has gained relatively wide application in studying nervous system structures. This technology has the advantage of reduced excitation of sensory nerve endings, and hence results in quasi-painless action. It has become clinically accepted modality for brain stimulation. However, theoretical and practical solutions for(More)
This study presents a multichannel ECG quality monitoring system, which continuously scans the leads' status (valid/lead-off) and quality (0-100%), according to the ECG components in the low, medium and high frequency bands. The system aims to detect the optimal moment to start the record of a 10s resting ECG within the 1 st minute of signal acquisition –(More)
This study presents a simple algorithm for pulse wave PW detection dedicated to real-time pulse sensing devices in an emergency. Two basic principles are implemented – identification of extrema by time-amplitude criteria, and validation of the most prominent rising edges preceding the systolic peak according to criteria for slope and similarity to neighbors(More)
Medical intervention by electrical current as applied to humans or animals may have tremendous therapeutic impact if delivered while being carefully controlled. Otherwise, the situation can be harmful in terms of injury or even become lethal. These consequences demand close inspection of all relevant biological and technical factors. Regarding methods to(More)
BACKGROUND AND OBJECTIVE A crucial factor for proper electrocardiogram (ECG) interpretation is the correct electrode placement in standard 12-lead ECG and extended 16-lead ECG for accurate diagnosis of acute myocardial infarctions. In the context of optimal patient care, we present and evaluate a new method for automated detection of reversals in peripheral(More)
This study presents a 2-stage heartbeat classifier of supraventricular (SVB) and ventricular (VB) beats. Stage 1 makes computationally-efficient classification of SVB-beats, using simple correlation threshold criterion for finding close match with a predominant normal (reference) beat template. The non-matched beats are next subjected to measurement of 20(More)
This study presents a two-stage heartbeat classifier. The first stage makes initial assignment of beats towards continuously updated beat templates of the predominant rhythm, and calculates a set of features, tracking the morphology and RR-interval variation, and correlation to noise robust average beat templates. The second stage implements a decision tree(More)